text: /*
   *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
   *
   *  Use of this source code is governed by a BSD-style license
   *  that can be found in the LICENSE file in the root of the source
   *  tree. An additional intellectual property rights grant can be found
   *  in the file PATENTS.  All contributing project authors may
   *  be found in the AUTHORS file in the root of the source tree.
   */
  
  #include <math.h>
  #include <limits.h>
  #include <stdio.h>
  
  #include "./vpx_scale_rtcd.h"
  #include "block.h"
  #include "onyx_int.h"
  #include "vp8/common/variance.h"
  #include "encodeintra.h"
  #include "vp8/common/setupintrarecon.h"
  #include "vp8/common/systemdependent.h"
  #include "mcomp.h"
  #include "firstpass.h"
  #include "vpx_scale/vpx_scale.h"
  #include "encodemb.h"
  #include "vp8/common/extend.h"
  #include "vpx_mem/vpx_mem.h"
  #include "vp8/common/swapyv12buffer.h"
  #include "rdopt.h"
  #include "vp8/common/quant_common.h"
  #include "encodemv.h"
  #include "encodeframe.h"
  
  /* #define OUTPUT_FPF 1 */
  
  extern void vp8cx_frame_init_quantizer(VP8_COMP *cpi);
  extern void vp8_set_mbmode_and_mvs(MACROBLOCK *x, MB_PREDICTION_MODE mb, int_mv *mv);
  extern void vp8_alloc_compressor_data(VP8_COMP *cpi);
  
  #define GFQ_ADJUSTMENT vp8_gf_boost_qadjustment[Q]
  extern int vp8_kf_boost_qadjustment[QINDEX_RANGE];
  
  extern const int vp8_gf_boost_qadjustment[QINDEX_RANGE];
  
  #define IIFACTOR   1.5
  #define IIKFACTOR1 1.40
  #define IIKFACTOR2 1.5
  #define RMAX       14.0
  #define GF_RMAX    48.0
  
  #define KF_MB_INTRA_MIN 300
  #define GF_MB_INTRA_MIN 200
  
  #define DOUBLE_DIVIDE_CHECK(X) ((X)<0?(X)-.000001:(X)+.000001)
  
  #define POW1 (double)cpi->oxcf.two_pass_vbrbias/100.0
  #define POW2 (double)cpi->oxcf.two_pass_vbrbias/100.0
  
  #define NEW_BOOST 1
  
  static int vscale_lookup[7] = {0, 1, 1, 2, 2, 3, 3};
  static int hscale_lookup[7] = {0, 0, 1, 1, 2, 2, 3};
  
  
  static const int cq_level[QINDEX_RANGE] =
  {
      0,0,1,1,2,3,3,4,4,5,6,6,7,8,8,9,
      9,10,11,11,12,13,13,14,15,15,16,17,17,18,19,20,
      20,21,22,22,23,24,24,25,26,27,27,28,29,30,30,31,
      32,33,33,34,35,36,36,37,38,39,39,40,41,42,42,43,
      44,45,46,46,47,48,49,50,50,51,52,53,54,55,55,56,
      57,58,59,60,60,61,62,63,64,65,66,67,67,68,69,70,
      71,72,73,74,75,75,76,77,78,79,80,81,82,83,84,85,
      86,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100
  };
  
  static void find_next_key_frame(VP8_COMP *cpi, FIRSTPASS_STATS *this_frame);
  
  /* Resets the first pass file to the given position using a relative seek
   * from the current position
   */
  static void reset_fpf_position(VP8_COMP *cpi, FIRSTPASS_STATS *Position)
  {
      cpi->twopass.stats_in = Position;
  }
  
  static int lookup_next_frame_stats(VP8_COMP *cpi, FIRSTPASS_STATS *next_frame)
  {
      if (cpi->twopass.stats_in >= cpi->twopass.stats_in_end)
          return EOF;
  
      *next_frame = *cpi->twopass.stats_in;
      return 1;
  }
  
  /* Read frame stats at an offset from the current position */
  static int read_frame_stats( VP8_COMP *cpi,
                               FIRSTPASS_STATS *frame_stats,
                               int offset )
  {
      FIRSTPASS_STATS * fps_ptr = cpi->twopass.stats_in;
  
      /* Check legality of offset */
      if ( offset >= 0 )
      {
          if ( &fps_ptr[offset] >= cpi->twopass.stats_in_end )
               return EOF;
      }
      else if ( offset < 0 )
      {
          if ( &fps_ptr[offset] < cpi->twopass.stats_in_start )
               return EOF;
      }
  
      *frame_stats = fps_ptr[offset];
      return 1;
  }
  
  static int input_stats(VP8_COMP *cpi, FIRSTPASS_STATS *fps)
  {
      if (cpi->twopass.stats_in >= cpi->twopass.stats_in_end)
          return EOF;
  
      *fps = *cpi->twopass.stats_in;
      cpi->twopass.stats_in =
           (void*)((char *)cpi->twopass.stats_in + sizeof(FIRSTPASS_STATS));
      return 1;
  }
  
  static void output_stats(const VP8_COMP            *cpi,
                           struct vpx_codec_pkt_list *pktlist,
                           FIRSTPASS_STATS            *stats)
  {
      struct vpx_codec_cx_pkt pkt;
      pkt.kind = VPX_CODEC_STATS_PKT;
      pkt.data.twopass_stats.buf = stats;
      pkt.data.twopass_stats.sz = sizeof(FIRSTPASS_STATS);
      vpx_codec_pkt_list_add(pktlist, &pkt);
      (void)cpi;
  /* TEMP debug code */
  #if OUTPUT_FPF
  
      {
          FILE *fpfile;
          fpfile = fopen("firstpass.stt", "a");
  
          fprintf(fpfile, "%12.0f %12.0f %12.0f %12.4f %12.4f %12.4f %12.4f"
                  " %12.4f %12.4f %12.4f %12.4f %12.4f %12.4f %12.4f %12.4f"
                  " %12.0f %12.0f %12.4f\n",
                  stats->frame,
                  stats->intra_error,
                  stats->coded_error,
                  stats->ssim_weighted_pred_err,
                  stats->pcnt_inter,
                  stats->pcnt_motion,
                  stats->pcnt_second_ref,
                  stats->pcnt_neutral,
                  stats->MVr,
                  stats->mvr_abs,
                  stats->MVc,
                  stats->mvc_abs,
                  stats->MVrv,
                  stats->MVcv,
                  stats->mv_in_out_count,
                  stats->new_mv_count,
                  stats->count,
                  stats->duration);
          fclose(fpfile);
      }
  #endif
  }
  
  static void zero_stats(FIRSTPASS_STATS *section)
  {
      section->frame      = 0.0;
      section->intra_error = 0.0;
      section->coded_error = 0.0;
      section->ssim_weighted_pred_err = 0.0;
      section->pcnt_inter  = 0.0;
      section->pcnt_motion  = 0.0;
      section->pcnt_second_ref = 0.0;
      section->pcnt_neutral = 0.0;
      section->MVr        = 0.0;
      section->mvr_abs     = 0.0;
      section->MVc        = 0.0;
      section->mvc_abs     = 0.0;
      section->MVrv       = 0.0;
      section->MVcv       = 0.0;
      section->mv_in_out_count  = 0.0;
      section->new_mv_count = 0.0;
      section->count      = 0.0;
      section->duration   = 1.0;
  }
  
  static void accumulate_stats(FIRSTPASS_STATS *section, FIRSTPASS_STATS *frame)
  {
      section->frame += frame->frame;
      section->intra_error += frame->intra_error;
      section->coded_error += frame->coded_error;
      section->ssim_weighted_pred_err += frame->ssim_weighted_pred_err;
      section->pcnt_inter  += frame->pcnt_inter;
      section->pcnt_motion += frame->pcnt_motion;
      section->pcnt_second_ref += frame->pcnt_second_ref;
      section->pcnt_neutral += frame->pcnt_neutral;
      section->MVr        += frame->MVr;
      section->mvr_abs     += frame->mvr_abs;
      section->MVc        += frame->MVc;
      section->mvc_abs     += frame->mvc_abs;
      section->MVrv       += frame->MVrv;
      section->MVcv       += frame->MVcv;
      section->mv_in_out_count  += frame->mv_in_out_count;
      section->new_mv_count += frame->new_mv_count;
      section->count      += frame->count;
      section->duration   += frame->duration;
  }
  
  static void subtract_stats(FIRSTPASS_STATS *section, FIRSTPASS_STATS *frame)
  {
      section->frame -= frame->frame;
      section->intra_error -= frame->intra_error;
      section->coded_error -= frame->coded_error;
      section->ssim_weighted_pred_err -= frame->ssim_weighted_pred_err;
      section->pcnt_inter  -= frame->pcnt_inter;
      section->pcnt_motion -= frame->pcnt_motion;
      section->pcnt_second_ref -= frame->pcnt_second_ref;
      section->pcnt_neutral -= frame->pcnt_neutral;
      section->MVr        -= frame->MVr;
      section->mvr_abs     -= frame->mvr_abs;
      section->MVc        -= frame->MVc;
      section->mvc_abs     -= frame->mvc_abs;
      section->MVrv       -= frame->MVrv;
      section->MVcv       -= frame->MVcv;
      section->mv_in_out_count  -= frame->mv_in_out_count;
      section->new_mv_count -= frame->new_mv_count;
      section->count      -= frame->count;
      section->duration   -= frame->duration;
  }
  
  static void avg_stats(FIRSTPASS_STATS *section)
  {
      if (section->count < 1.0)
          return;
  
      section->intra_error /= section->count;
      section->coded_error /= section->count;
      section->ssim_weighted_pred_err /= section->count;
      section->pcnt_inter  /= section->count;
      section->pcnt_second_ref /= section->count;
      section->pcnt_neutral /= section->count;
      section->pcnt_motion /= section->count;
      section->MVr        /= section->count;
      section->mvr_abs     /= section->count;
      section->MVc        /= section->count;
      section->mvc_abs     /= section->count;
      section->MVrv       /= section->count;
      section->MVcv       /= section->count;
      section->mv_in_out_count   /= section->count;
      section->duration   /= section->count;
  }
  
  /* Calculate a modified Error used in distributing bits between easier
   * and harder frames
   */
  static double calculate_modified_err(VP8_COMP *cpi, FIRSTPASS_STATS *this_frame)
  {
      double av_err = ( cpi->twopass.total_stats.ssim_weighted_pred_err /
                        cpi->twopass.total_stats.count );
      double this_err = this_frame->ssim_weighted_pred_err;
      double modified_err;
      (void)cpi;
      if (this_err > av_err)
          modified_err = av_err * pow((this_err / DOUBLE_DIVIDE_CHECK(av_err)), POW1);
      else
          modified_err = av_err * pow((this_err / DOUBLE_DIVIDE_CHECK(av_err)), POW2);
  
      return modified_err;
  }
  
  static const double weight_table[256] = {
  0.020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000,
  0.020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000,
  0.020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000,
  0.020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000,
  0.020000, 0.031250, 0.062500, 0.093750, 0.125000, 0.156250, 0.187500, 0.218750,
  0.250000, 0.281250, 0.312500, 0.343750, 0.375000, 0.406250, 0.437500, 0.468750,
  0.500000, 0.531250, 0.562500, 0.593750, 0.625000, 0.656250, 0.687500, 0.718750,
  0.750000, 0.781250, 0.812500, 0.843750, 0.875000, 0.906250, 0.937500, 0.968750,
  1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
  1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
  1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
  1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
  1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
  1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
  1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
  1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
  1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
  1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
  1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
  1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
  1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
  1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
  1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
  1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
  1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
  1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
  1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
  1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
  1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
  1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
  1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
  1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000
  };
  
  static double simple_weight(YV12_BUFFER_CONFIG *source)
  {
      int i, j;
  
      unsigned char *src = source->y_buffer;
      double sum_weights = 0.0;
  
      /* Loop throught the Y plane raw examining levels and creating a weight
       * for the image
       */
      i = source->y_height;
      do
      {
          j = source->y_width;
          do
          {
              sum_weights += weight_table[ *src];
              src++;
          }while(--j);
          src -= source->y_width;
          src += source->y_stride;
      }while(--i);
  
      sum_weights /= (source->y_height * source->y_width);
  
      return sum_weights;
  }
  
  
  /* This function returns the current per frame maximum bitrate target */
  static int frame_max_bits(VP8_COMP *cpi)
  {
      /* Max allocation for a single frame based on the max section guidelines
       * passed in and how many bits are left
       */
      int max_bits;
  
      /* For CBR we need to also consider buffer fullness.
       * If we are running below the optimal level then we need to gradually
       * tighten up on max_bits.
       */
      if (cpi->oxcf.end_usage == USAGE_STREAM_FROM_SERVER)
      {
          double buffer_fullness_ratio = (double)cpi->buffer_level / DOUBLE_DIVIDE_CHECK((double)cpi->oxcf.optimal_buffer_level);
  
          /* For CBR base this on the target average bits per frame plus the
           * maximum sedction rate passed in by the user
           */
          max_bits = (int)(cpi->av_per_frame_bandwidth * ((double)cpi->oxcf.two_pass_vbrmax_section / 100.0));
  
          /* If our buffer is below the optimum level */
          if (buffer_fullness_ratio < 1.0)
          {
              /* The lower of max_bits / 4 or cpi->av_per_frame_bandwidth / 4. */
              int min_max_bits = ((cpi->av_per_frame_bandwidth >> 2) < (max_bits >> 2)) ? cpi->av_per_frame_bandwidth >> 2 : max_bits >> 2;
  
              max_bits = (int)(max_bits * buffer_fullness_ratio);
  
              /* Lowest value we will set ... which should allow the buffer to
               * refill.
               */
              if (max_bits < min_max_bits)
                  max_bits = min_max_bits;
          }
      }
      /* VBR */
      else
      {
          /* For VBR base this on the bits and frames left plus the
           * two_pass_vbrmax_section rate passed in by the user
           */
          max_bits = (int)(((double)cpi->twopass.bits_left / (cpi->twopass.total_stats.count - (double)cpi->common.current_video_frame)) * ((double)cpi->oxcf.two_pass_vbrmax_section / 100.0));
      }
  
      /* Trap case where we are out of bits */
      if (max_bits < 0)
          max_bits = 0;
  
      return max_bits;
  }
  
  void vp8_init_first_pass(VP8_COMP *cpi)
  {
      zero_stats(&cpi->twopass.total_stats);
  }
  
  void vp8_end_first_pass(VP8_COMP *cpi)
  {
      output_stats(cpi, cpi->output_pkt_list, &cpi->twopass.total_stats);
  }
  
  static void zz_motion_search( VP8_COMP *cpi, MACROBLOCK * x,
                                YV12_BUFFER_CONFIG * raw_buffer,
                                int * raw_motion_err,
                                YV12_BUFFER_CONFIG * recon_buffer,
                                int * best_motion_err, int recon_yoffset)
  {
      MACROBLOCKD * const xd = & x->e_mbd;
      BLOCK *b = &x->block[0];
      BLOCKD *d = &x->e_mbd.block[0];
      unsigned char *src_ptr = (*(b->base_src) + b->src);
      int src_stride = b->src_stride;
      unsigned char *raw_ptr;
      int raw_stride = raw_buffer->y_stride;
      unsigned char *ref_ptr;
      int ref_stride = x->e_mbd.pre.y_stride;
  
      (void)cpi;
      /* Set up pointers for this macro block raw buffer */
      raw_ptr = (unsigned char *)(raw_buffer->y_buffer + recon_yoffset
                                  + d->offset);
      vp8_mse16x16 ( src_ptr, src_stride, raw_ptr, raw_stride,
                     (unsigned int *)(raw_motion_err));
  
      /* Set up pointers for this macro block recon buffer */
      xd->pre.y_buffer = recon_buffer->y_buffer + recon_yoffset;
      ref_ptr = (unsigned char *)(xd->pre.y_buffer + d->offset );
      vp8_mse16x16 ( src_ptr, src_stride, ref_ptr, ref_stride,
                     (unsigned int *)(best_motion_err));
  }
  
  static void first_pass_motion_search(VP8_COMP *cpi, MACROBLOCK *x,
                                       int_mv *ref_mv, MV *best_mv,
                                       YV12_BUFFER_CONFIG *recon_buffer,
                                       int *best_motion_err, int recon_yoffset )
  {
      MACROBLOCKD *const xd = & x->e_mbd;
      BLOCK *b = &x->block[0];
      BLOCKD *d = &x->e_mbd.block[0];
      int num00;
  
      int_mv tmp_mv;
      int_mv ref_mv_full;
  
      int tmp_err;
      int step_param = 3; /* Dont search over full range for first pass */
      int further_steps = (MAX_MVSEARCH_STEPS - 1) - step_param;
      int n;
      vp8_variance_fn_ptr_t v_fn_ptr = cpi->fn_ptr[BLOCK_16X16];
      int new_mv_mode_penalty = 256;
  
      /* override the default variance function to use MSE */
      v_fn_ptr.vf    = vp8_mse16x16;
  
      /* Set up pointers for this macro block recon buffer */
      xd->pre.y_buffer = recon_buffer->y_buffer + recon_yoffset;
  
      /* Initial step/diamond search centred on best mv */
      tmp_mv.as_int = 0;
      ref_mv_full.as_mv.col = ref_mv->as_mv.col>>3;
      ref_mv_full.as_mv.row = ref_mv->as_mv.row>>3;
      tmp_err = cpi->diamond_search_sad(x, b, d, &ref_mv_full, &tmp_mv, step_param,
                                        x->sadperbit16, &num00, &v_fn_ptr,
                                        x->mvcost, ref_mv);
      if ( tmp_err < INT_MAX-new_mv_mode_penalty )
          tmp_err += new_mv_mode_penalty;
  
      if (tmp_err < *best_motion_err)
      {
          *best_motion_err = tmp_err;
          best_mv->row = tmp_mv.as_mv.row;
          best_mv->col = tmp_mv.as_mv.col;
      }
  
      /* Further step/diamond searches as necessary */
      n = num00;
      num00 = 0;
  
      while (n < further_steps)
      {
          n++;
  
          if (num00)
              num00--;
          else
          {
              tmp_err = cpi->diamond_search_sad(x, b, d, &ref_mv_full, &tmp_mv,
                                                step_param + n, x->sadperbit16,
                                                &num00, &v_fn_ptr, x->mvcost,
                                                ref_mv);
              if ( tmp_err < INT_MAX-new_mv_mode_penalty )
                  tmp_err += new_mv_mode_penalty;
  
              if (tmp_err < *best_motion_err)
              {
                  *best_motion_err = tmp_err;
                  best_mv->row = tmp_mv.as_mv.row;
                  best_mv->col = tmp_mv.as_mv.col;
              }
          }
      }
  }
  
  void vp8_first_pass(VP8_COMP *cpi)
  {
      int mb_row, mb_col;
      MACROBLOCK *const x = & cpi->mb;
      VP8_COMMON *const cm = & cpi->common;
      MACROBLOCKD *const xd = & x->e_mbd;
  
      int recon_yoffset, recon_uvoffset;
      YV12_BUFFER_CONFIG *lst_yv12 = &cm->yv12_fb[cm->lst_fb_idx];
      YV12_BUFFER_CONFIG *new_yv12 = &cm->yv12_fb[cm->new_fb_idx];
      YV12_BUFFER_CONFIG *gld_yv12 = &cm->yv12_fb[cm->gld_fb_idx];
      int recon_y_stride = lst_yv12->y_stride;
      int recon_uv_stride = lst_yv12->uv_stride;
      int64_t intra_error = 0;
      int64_t coded_error = 0;
  
      int sum_mvr = 0, sum_mvc = 0;
      int sum_mvr_abs = 0, sum_mvc_abs = 0;
      int sum_mvrs = 0, sum_mvcs = 0;
      int mvcount = 0;
      int intercount = 0;
      int second_ref_count = 0;
      int intrapenalty = 256;
      int neutral_count = 0;
      int new_mv_count = 0;
      int sum_in_vectors = 0;
      uint32_t lastmv_as_int = 0;
  
      int_mv zero_ref_mv;
  
      zero_ref_mv.as_int = 0;
  
      vp8_clear_system_state();
  
      x->src = * cpi->Source;
      xd->pre = *lst_yv12;
      xd->dst = *new_yv12;
  
      x->partition_info = x->pi;
  
      xd->mode_info_context = cm->mi;
  
      if(!cm->use_bilinear_mc_filter)
      {
           xd->subpixel_predict        = vp8_sixtap_predict4x4;
           xd->subpixel_predict8x4     = vp8_sixtap_predict8x4;
           xd->subpixel_predict8x8     = vp8_sixtap_predict8x8;
           xd->subpixel_predict16x16   = vp8_sixtap_predict16x16;
       }
       else
       {
           xd->subpixel_predict        = vp8_bilinear_predict4x4;
           xd->subpixel_predict8x4     = vp8_bilinear_predict8x4;
           xd->subpixel_predict8x8     = vp8_bilinear_predict8x8;
           xd->subpixel_predict16x16   = vp8_bilinear_predict16x16;
       }
  
      vp8_build_block_offsets(x);
  
      /* set up frame new frame for intra coded blocks */
      vp8_setup_intra_recon(new_yv12);
      vp8cx_frame_init_quantizer(cpi);
  
      /* Initialise the MV cost table to the defaults */
      {
          int flag[2] = {1, 1};
          vp8_initialize_rd_consts(cpi, x, vp8_dc_quant(cm->base_qindex, cm->y1dc_delta_q));
          vpx_memcpy(cm->fc.mvc, vp8_default_mv_context, sizeof(vp8_default_mv_context));
          vp8_build_component_cost_table(cpi->mb.mvcost, (const MV_CONTEXT *) cm->fc.mvc, flag);
      }
  
      /* for each macroblock row in image */
      for (mb_row = 0; mb_row < cm->mb_rows; mb_row++)
      {
          int_mv best_ref_mv;
  
          best_ref_mv.as_int = 0;
  
          /* reset above block coeffs */
          xd->up_available = (mb_row != 0);
          recon_yoffset = (mb_row * recon_y_stride * 16);
          recon_uvoffset = (mb_row * recon_uv_stride * 8);
  
          /* Set up limit values for motion vectors to prevent them extending
           * outside the UMV borders
           */
          x->mv_row_min = -((mb_row * 16) + (VP8BORDERINPIXELS - 16));
          x->mv_row_max = ((cm->mb_rows - 1 - mb_row) * 16) + (VP8BORDERINPIXELS - 16);
  
  
          /* for each macroblock col in image */
          for (mb_col = 0; mb_col < cm->mb_cols; mb_col++)
          {
              int this_error;
              int gf_motion_error = INT_MAX;
              int use_dc_pred = (mb_col || mb_row) && (!mb_col || !mb_row);
  
              xd->dst.y_buffer = new_yv12->y_buffer + recon_yoffset;
              xd->dst.u_buffer = new_yv12->u_buffer + recon_uvoffset;
              xd->dst.v_buffer = new_yv12->v_buffer + recon_uvoffset;
              xd->left_available = (mb_col != 0);
  
              /* Copy current mb to a buffer */
              vp8_copy_mem16x16(x->src.y_buffer, x->src.y_stride, x->thismb, 16);
  
              /* do intra 16x16 prediction */
              this_error = vp8_encode_intra(cpi, x, use_dc_pred);
  
              /* "intrapenalty" below deals with situations where the intra
               * and inter error scores are very low (eg a plain black frame)
               * We do not have special cases in first pass for 0,0 and
               * nearest etc so all inter modes carry an overhead cost
               * estimate fot the mv. When the error score is very low this
               * causes us to pick all or lots of INTRA modes and throw lots
               * of key frames. This penalty adds a cost matching that of a
               * 0,0 mv to the intra case.
               */
              this_error += intrapenalty;
  
              /* Cumulative intra error total */
              intra_error += (int64_t)this_error;
  
              /* Set up limit values for motion vectors to prevent them
               * extending outside the UMV borders
               */
              x->mv_col_min = -((mb_col * 16) + (VP8BORDERINPIXELS - 16));
              x->mv_col_max = ((cm->mb_cols - 1 - mb_col) * 16) + (VP8BORDERINPIXELS - 16);
  
              /* Other than for the first frame do a motion search */
              if (cm->current_video_frame > 0)
              {
                  BLOCKD *d = &x->e_mbd.block[0];
                  MV tmp_mv = {0, 0};
                  int tmp_err;
                  int motion_error = INT_MAX;
                  int raw_motion_error = INT_MAX;
  
                  /* Simple 0,0 motion with no mv overhead */
                  zz_motion_search( cpi, x, cpi->last_frame_unscaled_source,
                                    &raw_motion_error, lst_yv12, &motion_error,
                                    recon_yoffset );
                  d->bmi.mv.as_mv.row = 0;
                  d->bmi.mv.as_mv.col = 0;
  
                  if (raw_motion_error < cpi->oxcf.encode_breakout)
                      goto skip_motion_search;
  
                  /* Test last reference frame using the previous best mv as the
                   * starting point (best reference) for the search
                   */
                  first_pass_motion_search(cpi, x, &best_ref_mv,
                                          &d->bmi.mv.as_mv, lst_yv12,
                                          &motion_error, recon_yoffset);
  
                  /* If the current best reference mv is not centred on 0,0
                   * then do a 0,0 based search as well
                   */
                  if (best_ref_mv.as_int)
                  {
                     tmp_err = INT_MAX;
                     first_pass_motion_search(cpi, x, &zero_ref_mv, &tmp_mv,
                                       lst_yv12, &tmp_err, recon_yoffset);
  
                     if ( tmp_err < motion_error )
                     {
                          motion_error = tmp_err;
                          d->bmi.mv.as_mv.row = tmp_mv.row;
                          d->bmi.mv.as_mv.col = tmp_mv.col;
                     }
                  }
  
                  /* Experimental search in a second reference frame ((0,0)
                   * based only)
                   */
                  if (cm->current_video_frame > 1)
                  {
                      first_pass_motion_search(cpi, x, &zero_ref_mv, &tmp_mv, gld_yv12, &gf_motion_error, recon_yoffset);
  
                      if ((gf_motion_error < motion_error) && (gf_motion_error < this_error))
                      {
                          second_ref_count++;
                      }
  
                      /* Reset to last frame as reference buffer */
                      xd->pre.y_buffer = lst_yv12->y_buffer + recon_yoffset;
                      xd->pre.u_buffer = lst_yv12->u_buffer + recon_uvoffset;
                      xd->pre.v_buffer = lst_yv12->v_buffer + recon_uvoffset;
                  }
  
  skip_motion_search:
                  /* Intra assumed best */
                  best_ref_mv.as_int = 0;
  
                  if (motion_error <= this_error)
                  {
                      /* Keep a count of cases where the inter and intra were
                       * very close and very low. This helps with scene cut
                       * detection for example in cropped clips with black bars
                       * at the sides or top and bottom.
                       */
                      if( (((this_error-intrapenalty) * 9) <=
                           (motion_error*10)) &&
                          (this_error < (2*intrapenalty)) )
                      {
                          neutral_count++;
                      }
  
                      d->bmi.mv.as_mv.row *= 8;
                      d->bmi.mv.as_mv.col *= 8;
                      this_error = motion_error;
                      vp8_set_mbmode_and_mvs(x, NEWMV, &d->bmi.mv);
                      vp8_encode_inter16x16y(x);
                      sum_mvr += d->bmi.mv.as_mv.row;
                      sum_mvr_abs += abs(d->bmi.mv.as_mv.row);
                      sum_mvc += d->bmi.mv.as_mv.col;
                      sum_mvc_abs += abs(d->bmi.mv.as_mv.col);
                      sum_mvrs += d->bmi.mv.as_mv.row * d->bmi.mv.as_mv.row;
                      sum_mvcs += d->bmi.mv.as_mv.col * d->bmi.mv.as_mv.col;
                      intercount++;
  
                      best_ref_mv.as_int = d->bmi.mv.as_int;
  
                      /* Was the vector non-zero */
                      if (d->bmi.mv.as_int)
                      {
                          mvcount++;
  
                          /* Was it different from the last non zero vector */
                          if ( d->bmi.mv.as_int != lastmv_as_int )
                              new_mv_count++;
                          lastmv_as_int = d->bmi.mv.as_int;
  
                          /* Does the Row vector point inwards or outwards */
                          if (mb_row < cm->mb_rows / 2)
                          {
                              if (d->bmi.mv.as_mv.row > 0)
                                  sum_in_vectors--;
                              else if (d->bmi.mv.as_mv.row < 0)
                                  sum_in_vectors++;
                          }
                          else if (mb_row > cm->mb_rows / 2)
                          {
                              if (d->bmi.mv.as_mv.row > 0)
                                  sum_in_vectors++;
                              else if (d->bmi.mv.as_mv.row < 0)
                                  sum_in_vectors--;
                          }
  
                          /* Does the Row vector point inwards or outwards */
                          if (mb_col < cm->mb_cols / 2)
                          {
                              if (d->bmi.mv.as_mv.col > 0)
                                  sum_in_vectors--;
                              else if (d->bmi.mv.as_mv.col < 0)
                                  sum_in_vectors++;
                          }
                          else if (mb_col > cm->mb_cols / 2)
                          {
                              if (d->bmi.mv.as_mv.col > 0)
                                  sum_in_vectors++;
                              else if (d->bmi.mv.as_mv.col < 0)
                                  sum_in_vectors--;
                          }
                      }
                  }
              }
  
              coded_error += (int64_t)this_error;
  
              /* adjust to the next column of macroblocks */
              x->src.y_buffer += 16;
              x->src.u_buffer += 8;
              x->src.v_buffer += 8;
  
              recon_yoffset += 16;
              recon_uvoffset += 8;
          }
  
          /* adjust to the next row of mbs */
          x->src.y_buffer += 16 * x->src.y_stride - 16 * cm->mb_cols;
          x->src.u_buffer += 8 * x->src.uv_stride - 8 * cm->mb_cols;
          x->src.v_buffer += 8 * x->src.uv_stride - 8 * cm->mb_cols;
  
          /* extend the recon for intra prediction */
          vp8_extend_mb_row(new_yv12, xd->dst.y_buffer + 16, xd->dst.u_buffer + 8, xd->dst.v_buffer + 8);
          vp8_clear_system_state();
      }
  
      vp8_clear_system_state();
      {
          double weight = 0.0;
  
          FIRSTPASS_STATS fps;
  
          fps.frame      = cm->current_video_frame ;
          fps.intra_error = (double)(intra_error >> 8);
          fps.coded_error = (double)(coded_error >> 8);
          weight = simple_weight(cpi->Source);
  
  
          if (weight < 0.1)
              weight = 0.1;
  
          fps.ssim_weighted_pred_err = fps.coded_error * weight;
  
          fps.pcnt_inter  = 0.0;
          fps.pcnt_motion = 0.0;
          fps.MVr        = 0.0;
          fps.mvr_abs     = 0.0;
          fps.MVc        = 0.0;
          fps.mvc_abs     = 0.0;
          fps.MVrv       = 0.0;
          fps.MVcv       = 0.0;
          fps.mv_in_out_count  = 0.0;
          fps.new_mv_count = 0.0;
          fps.count      = 1.0;
  
          fps.pcnt_inter   = 1.0 * (double)intercount / cm->MBs;
          fps.pcnt_second_ref = 1.0 * (double)second_ref_count / cm->MBs;
          fps.pcnt_neutral = 1.0 * (double)neutral_count / cm->MBs;
  
          if (mvcount > 0)
          {
              fps.MVr = (double)sum_mvr / (double)mvcount;
              fps.mvr_abs = (double)sum_mvr_abs / (double)mvcount;
              fps.MVc = (double)sum_mvc / (double)mvcount;
              fps.mvc_abs = (double)sum_mvc_abs / (double)mvcount;
              fps.MVrv = ((double)sum_mvrs - (fps.MVr * fps.MVr / (double)mvcount)) / (double)mvcount;
              fps.MVcv = ((double)sum_mvcs - (fps.MVc * fps.MVc / (double)mvcount)) / (double)mvcount;
              fps.mv_in_out_count = (double)sum_in_vectors / (double)(mvcount * 2);
              fps.new_mv_count = new_mv_count;
  
              fps.pcnt_motion = 1.0 * (double)mvcount / cpi->common.MBs;
          }
  
          /* TODO:  handle the case when duration is set to 0, or something less
           * than the full time between subsequent cpi->source_time_stamps
           */
          fps.duration = (double)(cpi->source->ts_end
                         - cpi->source->ts_start);
  
          /* don't want to do output stats with a stack variable! */
          memcpy(&cpi->twopass.this_frame_stats,
                 &fps,
                 sizeof(FIRSTPASS_STATS));
          output_stats(cpi, cpi->output_pkt_list, &cpi->twopass.this_frame_stats);
          accumulate_stats(&cpi->twopass.total_stats, &fps);
      }
  
      /* Copy the previous Last Frame into the GF buffer if specific
       * conditions for doing so are met
       */
      if ((cm->current_video_frame > 0) &&
          (cpi->twopass.this_frame_stats.pcnt_inter > 0.20) &&
          ((cpi->twopass.this_frame_stats.intra_error /
            DOUBLE_DIVIDE_CHECK(cpi->twopass.this_frame_stats.coded_error)) >
           2.0))
      {
          vp8_yv12_copy_frame(lst_yv12, gld_yv12);
      }
  
      /* swap frame pointers so last frame refers to the frame we just
       * compressed
       */
      vp8_swap_yv12_buffer(lst_yv12, new_yv12);
      vp8_yv12_extend_frame_borders(lst_yv12);
  
      /* Special case for the first frame. Copy into the GF buffer as a
       * second reference.
       */
      if (cm->current_video_frame == 0)
      {
          vp8_yv12_copy_frame(lst_yv12, gld_yv12);
      }
  
  
      /* use this to see what the first pass reconstruction looks like */
      if (0)
      {
          char filename[512];
          FILE *recon_file;
          sprintf(filename, "enc%04d.yuv", (int) cm->current_video_frame);
  
          if (cm->current_video_frame == 0)
              recon_file = fopen(filename, "wb");
          else
              recon_file = fopen(filename, "ab");
  
          (void) fwrite(lst_yv12->buffer_alloc, lst_yv12->frame_size, 1,
                        recon_file);
          fclose(recon_file);
      }
  
      cm->current_video_frame++;
  
  }
  extern const int vp8_bits_per_mb[2][QINDEX_RANGE];
  
  /* Estimate a cost per mb attributable to overheads such as the coding of
   * modes and motion vectors.
   * Currently simplistic in its assumptions for testing.
   */
  
  static double bitcost( double prob )
  {
    if (prob > 0.000122)
      return -log(prob) / log(2.0);
    else
      return 13.0;
  }
  static int64_t estimate_modemvcost(VP8_COMP *cpi,
                                       FIRSTPASS_STATS * fpstats)
  {
      int mv_cost;
      int64_t mode_cost;
  
      double av_pct_inter = fpstats->pcnt_inter / fpstats->count;
      double av_pct_motion = fpstats->pcnt_motion / fpstats->count;
      double av_intra = (1.0 - av_pct_inter);
  
      double zz_cost;
      double motion_cost;
      double intra_cost;
  
      zz_cost = bitcost(av_pct_inter - av_pct_motion);
      motion_cost = bitcost(av_pct_motion);
      intra_cost = bitcost(av_intra);
  
      /* Estimate of extra bits per mv overhead for mbs
       * << 9 is the normalization to the (bits * 512) used in vp8_bits_per_mb
       */
      mv_cost = ((int)(fpstats->new_mv_count / fpstats->count) * 8) << 9;
  
      /* Crude estimate of overhead cost from modes
       * << 9 is the normalization to (bits * 512) used in vp8_bits_per_mb
       */
      mode_cost = (int64_t)((((av_pct_inter - av_pct_motion) * zz_cost) +
                               (av_pct_motion * motion_cost) +
                               (av_intra * intra_cost)) * cpi->common.MBs) * 512;
  
      return mv_cost + mode_cost;
  }
  
  static double calc_correction_factor( double err_per_mb,
                                        double err_devisor,
                                        double pt_low,
                                        double pt_high,
                                        int Q )
  {
      double power_term;
      double error_term = err_per_mb / err_devisor;
      double correction_factor;
  
      /* Adjustment based on Q to power term. */
      power_term = pt_low + (Q * 0.01);
      power_term = (power_term > pt_high) ? pt_high : power_term;
  
      /* Adjustments to error term */
      /* TBD */
  
      /* Calculate correction factor */
      correction_factor = pow(error_term, power_term);
  
      /* Clip range */
      correction_factor =
          (correction_factor < 0.05)
              ? 0.05 : (correction_factor > 5.0) ? 5.0 : correction_factor;
  
      return correction_factor;
  }
  
  static int estimate_max_q(VP8_COMP *cpi,
                            FIRSTPASS_STATS * fpstats,
                            int section_target_bandwitdh,
                            int overhead_bits )
  {
      int Q;
      int num_mbs = cpi->common.MBs;
      int target_norm_bits_per_mb;
  
      double section_err = (fpstats->coded_error / fpstats->count);
      double err_per_mb = section_err / num_mbs;
      double err_correction_factor;
      double speed_correction = 1.0;
      int overhead_bits_per_mb;
  
      if (section_target_bandwitdh <= 0)
          return cpi->twopass.maxq_max_limit;       /* Highest value allowed */
  
      target_norm_bits_per_mb =
          (section_target_bandwitdh < (1 << 20))
              ? (512 * section_target_bandwitdh) / num_mbs
              : 512 * (section_target_bandwitdh / num_mbs);
  
      /* Calculate a corrective factor based on a rolling ratio of bits spent
       * vs target bits
       */
      if ((cpi->rolling_target_bits > 0) &&
          (cpi->active_worst_quality < cpi->worst_quality))
      {
          double rolling_ratio;
  
          rolling_ratio = (double)cpi->rolling_actual_bits /
                          (double)cpi->rolling_target_bits;
  
          if (rolling_ratio < 0.95)
              cpi->twopass.est_max_qcorrection_factor -= 0.005;
          else if (rolling_ratio > 1.05)
              cpi->twopass.est_max_qcorrection_factor += 0.005;
  
          cpi->twopass.est_max_qcorrection_factor =
              (cpi->twopass.est_max_qcorrection_factor < 0.1)
                  ? 0.1
                  : (cpi->twopass.est_max_qcorrection_factor > 10.0)
                      ? 10.0 : cpi->twopass.est_max_qcorrection_factor;
      }
  
      /* Corrections for higher compression speed settings
       * (reduced compression expected)
       */
      if ((cpi->compressor_speed == 3) || (cpi->compressor_speed == 1))
      {
          if (cpi->oxcf.cpu_used <= 5)
              speed_correction = 1.04 + (cpi->oxcf.cpu_used * 0.04);
          else
              speed_correction = 1.25;
      }
  
      /* Estimate of overhead bits per mb */
      /* Correction to overhead bits for min allowed Q. */
      overhead_bits_per_mb = overhead_bits / num_mbs;
      overhead_bits_per_mb = (int)(overhead_bits_per_mb *
                              pow( 0.98, (double)cpi->twopass.maxq_min_limit ));
  
      /* Try and pick a max Q that will be high enough to encode the
       * content at the given rate.
       */
      for (Q = cpi->twopass.maxq_min_limit; Q < cpi->twopass.maxq_max_limit; Q++)
      {
          int bits_per_mb_at_this_q;
  
          /* Error per MB based correction factor */
          err_correction_factor =
              calc_correction_factor(err_per_mb, 150.0, 0.40, 0.90, Q);
  
          bits_per_mb_at_this_q =
              vp8_bits_per_mb[INTER_FRAME][Q] + overhead_bits_per_mb;
  
          bits_per_mb_at_this_q = (int)(.5 + err_correction_factor
              * speed_correction * cpi->twopass.est_max_qcorrection_factor
              * cpi->twopass.section_max_qfactor
              * (double)bits_per_mb_at_this_q);
  
          /* Mode and motion overhead */
          /* As Q rises in real encode loop rd code will force overhead down
           * We make a crude adjustment for this here as *.98 per Q step.
           */
          overhead_bits_per_mb = (int)((double)overhead_bits_per_mb * 0.98);
  
          if (bits_per_mb_at_this_q <= target_norm_bits_per_mb)
              break;
      }
  
      /* Restriction on active max q for constrained quality mode. */
      if ( (cpi->oxcf.end_usage == USAGE_CONSTRAINED_QUALITY) &&
           (Q < cpi->cq_target_quality) )
      {
          Q = cpi->cq_target_quality;
      }
  
      /* Adjust maxq_min_limit and maxq_max_limit limits based on
       * average q observed in clip for non kf/gf.arf frames
       * Give average a chance to settle though.
       */
      if ( (cpi->ni_frames >
                    ((int)cpi->twopass.total_stats.count >> 8)) &&
           (cpi->ni_frames > 150) )
      {
          cpi->twopass.maxq_max_limit = ((cpi->ni_av_qi + 32) < cpi->worst_quality)
                                    ? (cpi->ni_av_qi + 32) : cpi->worst_quality;
          cpi->twopass.maxq_min_limit = ((cpi->ni_av_qi - 32) > cpi->best_quality)
                                    ? (cpi->ni_av_qi - 32) : cpi->best_quality;
      }
  
      return Q;
  }
  
  /* For cq mode estimate a cq level that matches the observed
   * complexity and data rate.
   */
  static int estimate_cq( VP8_COMP *cpi,
                          FIRSTPASS_STATS * fpstats,
                          int section_target_bandwitdh,
                          int overhead_bits )
  {
      int Q;
      int num_mbs = cpi->common.MBs;
      int target_norm_bits_per_mb;
  
      double section_err = (fpstats->coded_error / fpstats->count);
      double err_per_mb = section_err / num_mbs;
      double err_correction_factor;
      double speed_correction = 1.0;
      double clip_iiratio;
      double clip_iifactor;
      int overhead_bits_per_mb;
  
      if (0)
      {
          FILE *f = fopen("epmp.stt", "a");
          fprintf(f, "%10.2f\n", err_per_mb );
          fclose(f);
      }
  
      target_norm_bits_per_mb = (section_target_bandwitdh < (1 << 20))
                                ? (512 * section_target_bandwitdh) / num_mbs
                                : 512 * (section_target_bandwitdh / num_mbs);
  
      /* Estimate of overhead bits per mb */
      overhead_bits_per_mb = overhead_bits / num_mbs;
  
      /* Corrections for higher compression speed settings
       * (reduced compression expected)
       */
      if ((cpi->compressor_speed == 3) || (cpi->compressor_speed == 1))
      {
          if (cpi->oxcf.cpu_used <= 5)
              speed_correction = 1.04 + (cpi->oxcf.cpu_used * 0.04);
          else
              speed_correction = 1.25;
      }
  
      /* II ratio correction factor for clip as a whole */
      clip_iiratio = cpi->twopass.total_stats.intra_error /
                     DOUBLE_DIVIDE_CHECK(cpi->twopass.total_stats.coded_error);
      clip_iifactor = 1.0 - ((clip_iiratio - 10.0) * 0.025);
      if (clip_iifactor < 0.80)
          clip_iifactor = 0.80;
  
      /* Try and pick a Q that can encode the content at the given rate. */
      for (Q = 0; Q < MAXQ; Q++)
      {
          int bits_per_mb_at_this_q;
  
          /* Error per MB based correction factor */
          err_correction_factor =
              calc_correction_factor(err_per_mb, 100.0, 0.40, 0.90, Q);
  
          bits_per_mb_at_this_q =
              vp8_bits_per_mb[INTER_FRAME][Q] + overhead_bits_per_mb;
  
          bits_per_mb_at_this_q =
              (int)( .5 + err_correction_factor *
                          speed_correction *
                          clip_iifactor *
                          (double)bits_per_mb_at_this_q);
  
          /* Mode and motion overhead */
          /* As Q rises in real encode loop rd code will force overhead down
           * We make a crude adjustment for this here as *.98 per Q step.
           */
          overhead_bits_per_mb = (int)((double)overhead_bits_per_mb * 0.98);
  
          if (bits_per_mb_at_this_q <= target_norm_bits_per_mb)
              break;
      }
  
      /* Clip value to range "best allowed to (worst allowed - 1)" */
      Q = cq_level[Q];
      if ( Q >= cpi->worst_quality )
          Q = cpi->worst_quality - 1;
      if ( Q < cpi->best_quality )
          Q = cpi->best_quality;
  
      return Q;
  }
  
  static int estimate_q(VP8_COMP *cpi, double section_err, int section_target_bandwitdh)
  {
      int Q;
      int num_mbs = cpi->common.MBs;
      int target_norm_bits_per_mb;
  
      double err_per_mb = section_err / num_mbs;
      double err_correction_factor;
      double speed_correction = 1.0;
  
      target_norm_bits_per_mb = (section_target_bandwitdh < (1 << 20)) ? (512 * section_target_bandwitdh) / num_mbs : 512 * (section_target_bandwitdh / num_mbs);
  
      /* Corrections for higher compression speed settings
       * (reduced compression expected)
       */
      if ((cpi->compressor_speed == 3) || (cpi->compressor_speed == 1))
      {
          if (cpi->oxcf.cpu_used <= 5)
              speed_correction = 1.04 + (cpi->oxcf.cpu_used * 0.04);
          else
              speed_correction = 1.25;
      }
  
      /* Try and pick a Q that can encode the content at the given rate. */
      for (Q = 0; Q < MAXQ; Q++)
      {
          int bits_per_mb_at_this_q;
  
          /* Error per MB based correction factor */
          err_correction_factor =
              calc_correction_factor(err_per_mb, 150.0, 0.40, 0.90, Q);
  
          bits_per_mb_at_this_q =
              (int)( .5 + ( err_correction_factor *
                            speed_correction *
                            cpi->twopass.est_max_qcorrection_factor *
                            (double)vp8_bits_per_mb[INTER_FRAME][Q] / 1.0 ) );
  
          if (bits_per_mb_at_this_q <= target_norm_bits_per_mb)
              break;
      }
  
      return Q;
  }
  
  /* Estimate a worst case Q for a KF group */
  static int estimate_kf_group_q(VP8_COMP *cpi, double section_err, int section_target_bandwitdh, double group_iiratio)
  {
      int Q;
      int num_mbs = cpi->common.MBs;
      int target_norm_bits_per_mb = (512 * section_target_bandwitdh) / num_mbs;
      int bits_per_mb_at_this_q;
  
      double err_per_mb = section_err / num_mbs;
      double err_correction_factor;
      double speed_correction = 1.0;
      double current_spend_ratio = 1.0;
  
      double pow_highq = (POW1 < 0.6) ? POW1 + 0.3 : 0.90;
      double pow_lowq = (POW1 < 0.7) ? POW1 + 0.1 : 0.80;
  
      double iiratio_correction_factor = 1.0;
  
      double combined_correction_factor;
  
      /* Trap special case where the target is <= 0 */
      if (target_norm_bits_per_mb <= 0)
          return MAXQ * 2;
  
      /* Calculate a corrective factor based on a rolling ratio of bits spent
       *  vs target bits
       * This is clamped to the range 0.1 to 10.0
       */
      if (cpi->long_rolling_target_bits <= 0)
          current_spend_ratio = 10.0;
      else
      {
          current_spend_ratio = (double)cpi->long_rolling_actual_bits / (double)cpi->long_rolling_target_bits;
          current_spend_ratio = (current_spend_ratio > 10.0) ? 10.0 : (current_spend_ratio < 0.1) ? 0.1 : current_spend_ratio;
      }
  
      /* Calculate a correction factor based on the quality of prediction in
       * the sequence as indicated by intra_inter error score ratio (IIRatio)
       * The idea here is to favour subsampling in the hardest sections vs
       * the easyest.
       */
      iiratio_correction_factor = 1.0 - ((group_iiratio - 6.0) * 0.1);
  
      if (iiratio_correction_factor < 0.5)
          iiratio_correction_factor = 0.5;
  
      /* Corrections for higher compression speed settings
       * (reduced compression expected)
       */
      if ((cpi->compressor_speed == 3) || (cpi->compressor_speed == 1))
      {
          if (cpi->oxcf.cpu_used <= 5)
              speed_correction = 1.04 + (cpi->oxcf.cpu_used * 0.04);
          else
              speed_correction = 1.25;
      }
  
      /* Combine the various factors calculated above */
      combined_correction_factor = speed_correction * iiratio_correction_factor * current_spend_ratio;
  
      /* Try and pick a Q that should be high enough to encode the content at
       * the given rate.
       */
      for (Q = 0; Q < MAXQ; Q++)
      {
          /* Error per MB based correction factor */
          err_correction_factor =
              calc_correction_factor(err_per_mb, 150.0, pow_lowq, pow_highq, Q);
  
          bits_per_mb_at_this_q =
              (int)(.5 + ( err_correction_factor *
                           combined_correction_factor *
                           (double)vp8_bits_per_mb[INTER_FRAME][Q]) );
  
          if (bits_per_mb_at_this_q <= target_norm_bits_per_mb)
              break;
      }
  
      /* If we could not hit the target even at Max Q then estimate what Q
       * would have been required
       */
      while ((bits_per_mb_at_this_q > target_norm_bits_per_mb)  && (Q < (MAXQ * 2)))
      {
  
          bits_per_mb_at_this_q = (int)(0.96 * bits_per_mb_at_this_q);
          Q++;
      }
  
      if (0)
      {
          FILE *f = fopen("estkf_q.stt", "a");
          fprintf(f, "%8d %8d %8d %8.2f %8.3f %8.2f %8.3f %8.3f %8.3f %8d\n", cpi->common.current_video_frame, bits_per_mb_at_this_q,
                  target_norm_bits_per_mb, err_per_mb, err_correction_factor,
                  current_spend_ratio, group_iiratio, iiratio_correction_factor,
                  (double)cpi->buffer_level / (double)cpi->oxcf.optimal_buffer_level, Q);
          fclose(f);
      }
  
      return Q;
  }
  
  extern void vp8_new_framerate(VP8_COMP *cpi, double framerate);
  
  void vp8_init_second_pass(VP8_COMP *cpi)
  {
      FIRSTPASS_STATS this_frame;
      FIRSTPASS_STATS *start_pos;
  
      double two_pass_min_rate = (double)(cpi->oxcf.target_bandwidth * cpi->oxcf.two_pass_vbrmin_section / 100);
  
      zero_stats(&cpi->twopass.total_stats);
      zero_stats(&cpi->twopass.total_left_stats);
  
      if (!cpi->twopass.stats_in_end)
          return;
  
      cpi->twopass.total_stats = *cpi->twopass.stats_in_end;
      cpi->twopass.total_left_stats = cpi->twopass.total_stats;
  
      /* each frame can have a different duration, as the frame rate in the
       * source isn't guaranteed to be constant.   The frame rate prior to
       * the first frame encoded in the second pass is a guess.  However the
       * sum duration is not. Its calculated based on the actual durations of
       * all frames from the first pass.
       */
      vp8_new_framerate(cpi, 10000000.0 * cpi->twopass.total_stats.count / cpi->twopass.total_stats.duration);
  
      cpi->output_framerate = cpi->framerate;
      cpi->twopass.bits_left = (int64_t)(cpi->twopass.total_stats.duration * cpi->oxcf.target_bandwidth / 10000000.0) ;
      cpi->twopass.bits_left -= (int64_t)(cpi->twopass.total_stats.duration * two_pass_min_rate / 10000000.0);
  
      /* Calculate a minimum intra value to be used in determining the IIratio
       * scores used in the second pass. We have this minimum to make sure
       * that clips that are static but "low complexity" in the intra domain
       * are still boosted appropriately for KF/GF/ARF
       */
      cpi->twopass.kf_intra_err_min = KF_MB_INTRA_MIN * cpi->common.MBs;
      cpi->twopass.gf_intra_err_min = GF_MB_INTRA_MIN * cpi->common.MBs;
  
      /* Scan the first pass file and calculate an average Intra / Inter error
       * score ratio for the sequence
       */
      {
          double sum_iiratio = 0.0;
          double IIRatio;
  
          start_pos = cpi->twopass.stats_in; /* Note starting "file" position */
  
          while (input_stats(cpi, &this_frame) != EOF)
          {
              IIRatio = this_frame.intra_error / DOUBLE_DIVIDE_CHECK(this_frame.coded_error);
              IIRatio = (IIRatio < 1.0) ? 1.0 : (IIRatio > 20.0) ? 20.0 : IIRatio;
              sum_iiratio += IIRatio;
          }
  
          cpi->twopass.avg_iiratio = sum_iiratio / DOUBLE_DIVIDE_CHECK((double)cpi->twopass.total_stats.count);
  
          /* Reset file position */
          reset_fpf_position(cpi, start_pos);
      }
  
      /* Scan the first pass file and calculate a modified total error based
       * upon the bias/power function used to allocate bits
       */
      {
          start_pos = cpi->twopass.stats_in;  /* Note starting "file" position */
  
          cpi->twopass.modified_error_total = 0.0;
          cpi->twopass.modified_error_used = 0.0;
  
          while (input_stats(cpi, &this_frame) != EOF)
          {
              cpi->twopass.modified_error_total += calculate_modified_err(cpi, &this_frame);
          }
          cpi->twopass.modified_error_left = cpi->twopass.modified_error_total;
  
          reset_fpf_position(cpi, start_pos);  /* Reset file position */
  
      }
  }
  
  void vp8_end_second_pass(VP8_COMP *cpi)
  {
     (void)cpi;
  }
  
  /* This function gives and estimate of how badly we believe the prediction
   * quality is decaying from frame to frame.
   */
  static double get_prediction_decay_rate(VP8_COMP *cpi, FIRSTPASS_STATS *next_frame)
  {
      double prediction_decay_rate;
      double motion_decay;
      double motion_pct = next_frame->pcnt_motion;
  
      (void)cpi;
      /* Initial basis is the % mbs inter coded */
      prediction_decay_rate = next_frame->pcnt_inter;
      /* High % motion -> somewhat higher decay rate */
      motion_decay = (1.0 - (motion_pct / 20.0));
      if (motion_decay < prediction_decay_rate)
          prediction_decay_rate = motion_decay;
  
      /* Adjustment to decay rate based on speed of motion */
      {
          double this_mv_rabs;
          double this_mv_cabs;
          double distance_factor;
  
          this_mv_rabs = fabs(next_frame->mvr_abs * motion_pct);
          this_mv_cabs = fabs(next_frame->mvc_abs * motion_pct);
  
          distance_factor = sqrt((this_mv_rabs * this_mv_rabs) +
                                 (this_mv_cabs * this_mv_cabs)) / 250.0;
          distance_factor = ((distance_factor > 1.0)
                                  ? 0.0 : (1.0 - distance_factor));
          if (distance_factor < prediction_decay_rate)
              prediction_decay_rate = distance_factor;
      }
  
      return prediction_decay_rate;
  }
  
  /* Function to test for a condition where a complex transition is followed
   * by a static section. For example in slide shows where there is a fade
   * between slides. This is to help with more optimal kf and gf positioning.
   */
  static int detect_transition_to_still(
      VP8_COMP *cpi,
      int frame_interval,
      int still_interval,
      double loop_decay_rate,
      double decay_accumulator )
  {
      int trans_to_still = 0;
  
      /* Break clause to detect very still sections after motion
       * For example a static image after a fade or other transition
       * instead of a clean scene cut.
       */
      if ( (frame_interval > MIN_GF_INTERVAL) &&
           (loop_decay_rate >= 0.999) &&
           (decay_accumulator < 0.9) )
      {
          int j;
          FIRSTPASS_STATS * position = cpi->twopass.stats_in;
          FIRSTPASS_STATS tmp_next_frame;
          double decay_rate;
  
          /* Look ahead a few frames to see if static condition persists... */
          for ( j = 0; j < still_interval; j++ )
          {
              if (EOF == input_stats(cpi, &tmp_next_frame))
                  break;
  
              decay_rate = get_prediction_decay_rate(cpi, &tmp_next_frame);
              if ( decay_rate < 0.999 )
                  break;
          }
          /* Reset file position */
          reset_fpf_position(cpi, position);
  
          /* Only if it does do we signal a transition to still */
          if ( j == still_interval )
              trans_to_still = 1;
      }
  
      return trans_to_still;
  }
  
  /* This function detects a flash through the high relative pcnt_second_ref
   * score in the frame following a flash frame. The offset passed in should
   * reflect this
   */
  static int detect_flash( VP8_COMP *cpi, int offset )
  {
      FIRSTPASS_STATS next_frame;
  
      int flash_detected = 0;
  
      /* Read the frame data. */
      /* The return is 0 (no flash detected) if not a valid frame */
      if ( read_frame_stats(cpi, &next_frame, offset) != EOF )
      {
          /* What we are looking for here is a situation where there is a
           * brief break in prediction (such as a flash) but subsequent frames
           * are reasonably well predicted by an earlier (pre flash) frame.
           * The recovery after a flash is indicated by a high pcnt_second_ref
           * comapred to pcnt_inter.
           */
          if ( (next_frame.pcnt_second_ref > next_frame.pcnt_inter) &&
               (next_frame.pcnt_second_ref >= 0.5 ) )
          {
              flash_detected = 1;
  
              /*if (1)
              {
                  FILE *f = fopen("flash.stt", "a");
                  fprintf(f, "%8.0f %6.2f %6.2f\n",
                      next_frame.frame,
                      next_frame.pcnt_inter,
                      next_frame.pcnt_second_ref);
                  fclose(f);
              }*/
          }
      }
  
      return flash_detected;
  }
  
  /* Update the motion related elements to the GF arf boost calculation */
  static void accumulate_frame_motion_stats(
      VP8_COMP *cpi,
      FIRSTPASS_STATS * this_frame,
      double * this_frame_mv_in_out,
      double * mv_in_out_accumulator,
      double * abs_mv_in_out_accumulator,
      double * mv_ratio_accumulator )
  {
      double this_frame_mvr_ratio;
      double this_frame_mvc_ratio;
      double motion_pct;
  
      (void)cpi;
      /* Accumulate motion stats. */
      motion_pct = this_frame->pcnt_motion;
  
      /* Accumulate Motion In/Out of frame stats */
      *this_frame_mv_in_out = this_frame->mv_in_out_count * motion_pct;
      *mv_in_out_accumulator += this_frame->mv_in_out_count * motion_pct;
      *abs_mv_in_out_accumulator +=
          fabs(this_frame->mv_in_out_count * motion_pct);
  
      /* Accumulate a measure of how uniform (or conversely how random)
       * the motion field is. (A ratio of absmv / mv)
       */
      if (motion_pct > 0.05)
      {
          this_frame_mvr_ratio = fabs(this_frame->mvr_abs) /
                                 DOUBLE_DIVIDE_CHECK(fabs(this_frame->MVr));
  
          this_frame_mvc_ratio = fabs(this_frame->mvc_abs) /
                                 DOUBLE_DIVIDE_CHECK(fabs(this_frame->MVc));
  
           *mv_ratio_accumulator +=
              (this_frame_mvr_ratio < this_frame->mvr_abs)
                  ? (this_frame_mvr_ratio * motion_pct)
                  : this_frame->mvr_abs * motion_pct;
  
          *mv_ratio_accumulator +=
              (this_frame_mvc_ratio < this_frame->mvc_abs)
                  ? (this_frame_mvc_ratio * motion_pct)
                  : this_frame->mvc_abs * motion_pct;
  
      }
  }
  
  /* Calculate a baseline boost number for the current frame. */
  static double calc_frame_boost(
      VP8_COMP *cpi,
      FIRSTPASS_STATS * this_frame,
      double this_frame_mv_in_out )
  {
      double frame_boost;
  
      /* Underlying boost factor is based on inter intra error ratio */
      if (this_frame->intra_error > cpi->twopass.gf_intra_err_min)
          frame_boost = (IIFACTOR * this_frame->intra_error /
                        DOUBLE_DIVIDE_CHECK(this_frame->coded_error));
      else
          frame_boost = (IIFACTOR * cpi->twopass.gf_intra_err_min /
                        DOUBLE_DIVIDE_CHECK(this_frame->coded_error));
  
      /* Increase boost for frames where new data coming into frame
       * (eg zoom out). Slightly reduce boost if there is a net balance
       * of motion out of the frame (zoom in).
       * The range for this_frame_mv_in_out is -1.0 to +1.0
       */
      if (this_frame_mv_in_out > 0.0)
          frame_boost += frame_boost * (this_frame_mv_in_out * 2.0);
      /* In extreme case boost is halved */
      else
          frame_boost += frame_boost * (this_frame_mv_in_out / 2.0);
  
      /* Clip to maximum */
      if (frame_boost > GF_RMAX)
          frame_boost = GF_RMAX;
  
      return frame_boost;
  }
  
  #if NEW_BOOST
  static int calc_arf_boost(
      VP8_COMP *cpi,
      int offset,
      int f_frames,
      int b_frames,
      int *f_boost,
      int *b_boost )
  {
      FIRSTPASS_STATS this_frame;
  
      int i;
      double boost_score = 0.0;
      double mv_ratio_accumulator = 0.0;
      double decay_accumulator = 1.0;
      double this_frame_mv_in_out = 0.0;
      double mv_in_out_accumulator = 0.0;
      double abs_mv_in_out_accumulator = 0.0;
      double r;
      int flash_detected = 0;
  
      /* Search forward from the proposed arf/next gf position */
      for ( i = 0; i < f_frames; i++ )
      {
          if ( read_frame_stats(cpi, &this_frame, (i+offset)) == EOF )
              break;
  
          /* Update the motion related elements to the boost calculation */
          accumulate_frame_motion_stats( cpi, &this_frame,
              &this_frame_mv_in_out, &mv_in_out_accumulator,
              &abs_mv_in_out_accumulator, &mv_ratio_accumulator );
  
          /* Calculate the baseline boost number for this frame */
          r = calc_frame_boost( cpi, &this_frame, this_frame_mv_in_out );
  
          /* We want to discount the the flash frame itself and the recovery
           * frame that follows as both will have poor scores.
           */
          flash_detected = detect_flash(cpi, (i+offset)) ||
                           detect_flash(cpi, (i+offset+1));
  
          /* Cumulative effect of prediction quality decay */
          if ( !flash_detected )
          {
              decay_accumulator =
                  decay_accumulator *
                  get_prediction_decay_rate(cpi, &this_frame);
              decay_accumulator =
                  decay_accumulator < 0.1 ? 0.1 : decay_accumulator;
          }
          boost_score += (decay_accumulator * r);
  
          /* Break out conditions. */
          if  ( (!flash_detected) &&
                ((mv_ratio_accumulator > 100.0) ||
                 (abs_mv_in_out_accumulator > 3.0) ||
                 (mv_in_out_accumulator < -2.0) ) )
          {
              break;
          }
      }
  
      *f_boost = (int)(boost_score * 100.0) >> 4;
  
      /* Reset for backward looking loop */
      boost_score = 0.0;
      mv_ratio_accumulator = 0.0;
      decay_accumulator = 1.0;
      this_frame_mv_in_out = 0.0;
      mv_in_out_accumulator = 0.0;
      abs_mv_in_out_accumulator = 0.0;
  
      /* Search forward from the proposed arf/next gf position */
      for ( i = -1; i >= -b_frames; i-- )
      {
          if ( read_frame_stats(cpi, &this_frame, (i+offset)) == EOF )
              break;
  
          /* Update the motion related elements to the boost calculation */
          accumulate_frame_motion_stats( cpi, &this_frame,
              &this_frame_mv_in_out, &mv_in_out_accumulator,
              &abs_mv_in_out_accumulator, &mv_ratio_accumulator );
  
          /* Calculate the baseline boost number for this frame */
          r = calc_frame_boost( cpi, &this_frame, this_frame_mv_in_out );
  
          /* We want to discount the the flash frame itself and the recovery
           * frame that follows as both will have poor scores.
           */
          flash_detected = detect_flash(cpi, (i+offset)) ||
                           detect_flash(cpi, (i+offset+1));
  
          /* Cumulative effect of prediction quality decay */
          if ( !flash_detected )
          {
              decay_accumulator =
                  decay_accumulator *
                  get_prediction_decay_rate(cpi, &this_frame);
              decay_accumulator =
                  decay_accumulator < 0.1 ? 0.1 : decay_accumulator;
          }
  
          boost_score += (decay_accumulator * r);
  
          /* Break out conditions. */
          if  ( (!flash_detected) &&
                ((mv_ratio_accumulator > 100.0) ||
                 (abs_mv_in_out_accumulator > 3.0) ||
                 (mv_in_out_accumulator < -2.0) ) )
          {
              break;
          }
      }
      *b_boost = (int)(boost_score * 100.0) >> 4;
  
      return (*f_boost + *b_boost);
  }
  #endif
  
  /* Analyse and define a gf/arf group . */
  static void define_gf_group(VP8_COMP *cpi, FIRSTPASS_STATS *this_frame)
  {
      FIRSTPASS_STATS next_frame;
      FIRSTPASS_STATS *start_pos;
      int i;
      double r;
      double boost_score = 0.0;
      double old_boost_score = 0.0;
      double gf_group_err = 0.0;
      double gf_first_frame_err = 0.0;
      double mod_frame_err = 0.0;
  
      double mv_ratio_accumulator = 0.0;
      double decay_accumulator = 1.0;
  
      double loop_decay_rate = 1.00;          /* Starting decay rate */
  
      double this_frame_mv_in_out = 0.0;
      double mv_in_out_accumulator = 0.0;
      double abs_mv_in_out_accumulator = 0.0;
      double mod_err_per_mb_accumulator = 0.0;
  
      int max_bits = frame_max_bits(cpi);     /* Max for a single frame */
  
      unsigned int allow_alt_ref =
                      cpi->oxcf.play_alternate && cpi->oxcf.lag_in_frames;
  
      int alt_boost = 0;
      int f_boost = 0;
      int b_boost = 0;
      int flash_detected;
  
      cpi->twopass.gf_group_bits = 0;
      cpi->twopass.gf_decay_rate = 0;
  
      vp8_clear_system_state();
  
      start_pos = cpi->twopass.stats_in;
  
      vpx_memset(&next_frame, 0, sizeof(next_frame)); /* assure clean */
  
      /* Load stats for the current frame. */
      mod_frame_err = calculate_modified_err(cpi, this_frame);
  
      /* Note the error of the frame at the start of the group (this will be
       * the GF frame error if we code a normal gf
       */
      gf_first_frame_err = mod_frame_err;
  
      /* Special treatment if the current frame is a key frame (which is also
       * a gf). If it is then its error score (and hence bit allocation) need
       * to be subtracted out from the calculation for the GF group
       */
      if (cpi->common.frame_type == KEY_FRAME)
          gf_group_err -= gf_first_frame_err;
  
      /* Scan forward to try and work out how many frames the next gf group
       * should contain and what level of boost is appropriate for the GF
       * or ARF that will be coded with the group
       */
      i = 0;
  
      while (((i < cpi->twopass.static_scene_max_gf_interval) ||
              ((cpi->twopass.frames_to_key - i) < MIN_GF_INTERVAL)) &&
             (i < cpi->twopass.frames_to_key))
      {
          i++;
  
          /* Accumulate error score of frames in this gf group */
          mod_frame_err = calculate_modified_err(cpi, this_frame);
  
          gf_group_err += mod_frame_err;
  
          mod_err_per_mb_accumulator +=
              mod_frame_err / DOUBLE_DIVIDE_CHECK((double)cpi->common.MBs);
  
          if (EOF == input_stats(cpi, &next_frame))
              break;
  
          /* Test for the case where there is a brief flash but the prediction
           * quality back to an earlier frame is then restored.
           */
          flash_detected = detect_flash(cpi, 0);
  
          /* Update the motion related elements to the boost calculation */
          accumulate_frame_motion_stats( cpi, &next_frame,
              &this_frame_mv_in_out, &mv_in_out_accumulator,
              &abs_mv_in_out_accumulator, &mv_ratio_accumulator );
  
          /* Calculate a baseline boost number for this frame */
          r = calc_frame_boost( cpi, &next_frame, this_frame_mv_in_out );
  
          /* Cumulative effect of prediction quality decay */
          if ( !flash_detected )
          {
              loop_decay_rate = get_prediction_decay_rate(cpi, &next_frame);
              decay_accumulator = decay_accumulator * loop_decay_rate;
              decay_accumulator =
                  decay_accumulator < 0.1 ? 0.1 : decay_accumulator;
          }
          boost_score += (decay_accumulator * r);
  
          /* Break clause to detect very still sections after motion
           * For example a staic image after a fade or other transition.
           */
          if ( detect_transition_to_still( cpi, i, 5,
                                           loop_decay_rate,
                                           decay_accumulator ) )
          {
              allow_alt_ref = 0;
              boost_score = old_boost_score;
              break;
          }
  
          /* Break out conditions. */
          if  (
              /* Break at cpi->max_gf_interval unless almost totally static */
              (i >= cpi->max_gf_interval && (decay_accumulator < 0.995)) ||
              (
                  /* Dont break out with a very short interval */
                  (i > MIN_GF_INTERVAL) &&
                  /* Dont break out very close to a key frame */
                  ((cpi->twopass.frames_to_key - i) >= MIN_GF_INTERVAL) &&
                  ((boost_score > 20.0) || (next_frame.pcnt_inter < 0.75)) &&
                  (!flash_detected) &&
                  ((mv_ratio_accumulator > 100.0) ||
                   (abs_mv_in_out_accumulator > 3.0) ||
                   (mv_in_out_accumulator < -2.0) ||
                   ((boost_score - old_boost_score) < 2.0))
              ) )
          {
              boost_score = old_boost_score;
              break;
          }
  
          vpx_memcpy(this_frame, &next_frame, sizeof(*this_frame));
  
          old_boost_score = boost_score;
      }
  
      cpi->twopass.gf_decay_rate =
          (i > 0) ? (int)(100.0 * (1.0 - decay_accumulator)) / i : 0;
  
      /* When using CBR apply additional buffer related upper limits */
      if (cpi->oxcf.end_usage == USAGE_STREAM_FROM_SERVER)
      {
          double max_boost;
  
          /* For cbr apply buffer related limits */
          if (cpi->drop_frames_allowed)
          {
              int64_t df_buffer_level = cpi->oxcf.drop_frames_water_mark *
                                    (cpi->oxcf.optimal_buffer_level / 100);
  
              if (cpi->buffer_level > df_buffer_level)
                  max_boost = ((double)((cpi->buffer_level - df_buffer_level) * 2 / 3) * 16.0) / DOUBLE_DIVIDE_CHECK((double)cpi->av_per_frame_bandwidth);
              else
                  max_boost = 0.0;
          }
          else if (cpi->buffer_level > 0)
          {
              max_boost = ((double)(cpi->buffer_level * 2 / 3) * 16.0) / DOUBLE_DIVIDE_CHECK((double)cpi->av_per_frame_bandwidth);
          }
          else
          {
              max_boost = 0.0;
          }
  
          if (boost_score > max_boost)
              boost_score = max_boost;
      }
  
      /* Dont allow conventional gf too near the next kf */
      if ((cpi->twopass.frames_to_key - i) < MIN_GF_INTERVAL)
      {
          while (i < cpi->twopass.frames_to_key)
          {
              i++;
  
              if (EOF == input_stats(cpi, this_frame))
                  break;
  
              if (i < cpi->twopass.frames_to_key)
              {
                  mod_frame_err = calculate_modified_err(cpi, this_frame);
                  gf_group_err += mod_frame_err;
              }
          }
      }
  
      cpi->gfu_boost = (int)(boost_score * 100.0) >> 4;
  
  #if NEW_BOOST
      /* Alterrnative boost calculation for alt ref */
      alt_boost = calc_arf_boost( cpi, 0, (i-1), (i-1), &f_boost, &b_boost );
  #endif
  
      /* Should we use the alternate refernce frame */
      if (allow_alt_ref &&
          (i >= MIN_GF_INTERVAL) &&
          /* dont use ARF very near next kf */
          (i <= (cpi->twopass.frames_to_key - MIN_GF_INTERVAL)) &&
  #if NEW_BOOST
          ((next_frame.pcnt_inter > 0.75) ||
           (next_frame.pcnt_second_ref > 0.5)) &&
          ((mv_in_out_accumulator / (double)i > -0.2) ||
           (mv_in_out_accumulator > -2.0)) &&
          (b_boost > 100) &&
          (f_boost > 100) )
  #else
          (next_frame.pcnt_inter > 0.75) &&
          ((mv_in_out_accumulator / (double)i > -0.2) ||
           (mv_in_out_accumulator > -2.0)) &&
          (cpi->gfu_boost > 100) &&
          (cpi->twopass.gf_decay_rate <=
              (ARF_DECAY_THRESH + (cpi->gfu_boost / 200))) )
  #endif
      {
          int Boost;
          int allocation_chunks;
          int Q = (cpi->oxcf.fixed_q < 0)
                  ? cpi->last_q[INTER_FRAME] : cpi->oxcf.fixed_q;
          int tmp_q;
          int arf_frame_bits = 0;
          int group_bits;
  
  #if NEW_BOOST
          cpi->gfu_boost = alt_boost;
  #endif
  
          /* Estimate the bits to be allocated to the group as a whole */
          if ((cpi->twopass.kf_group_bits > 0) &&
              (cpi->twopass.kf_group_error_left > 0))
          {
              group_bits = (int)((double)cpi->twopass.kf_group_bits *
                  (gf_group_err / (double)cpi->twopass.kf_group_error_left));
          }
          else
              group_bits = 0;
  
          /* Boost for arf frame */
  #if NEW_BOOST
          Boost = (alt_boost * GFQ_ADJUSTMENT) / 100;
  #else
          Boost = (cpi->gfu_boost * 3 * GFQ_ADJUSTMENT) / (2 * 100);
  #endif
          Boost += (i * 50);
  
          /* Set max and minimum boost and hence minimum allocation */
          if (Boost > ((cpi->baseline_gf_interval + 1) * 200))
              Boost = ((cpi->baseline_gf_interval + 1) * 200);
          else if (Boost < 125)
              Boost = 125;
  
          allocation_chunks = (i * 100) + Boost;
  
          /* Normalize Altboost and allocations chunck down to prevent overflow */
          while (Boost > 1000)
          {
              Boost /= 2;
              allocation_chunks /= 2;
          }
  
          /* Calculate the number of bits to be spent on the arf based on the
           * boost number
           */
          arf_frame_bits = (int)((double)Boost * (group_bits /
                                 (double)allocation_chunks));
  
          /* Estimate if there are enough bits available to make worthwhile use
           * of an arf.
           */
          tmp_q = estimate_q(cpi, mod_frame_err, (int)arf_frame_bits);
  
          /* Only use an arf if it is likely we will be able to code
           * it at a lower Q than the surrounding frames.
           */
          if (tmp_q < cpi->worst_quality)
          {
              int half_gf_int;
              int frames_after_arf;
              int frames_bwd = cpi->oxcf.arnr_max_frames - 1;
              int frames_fwd = cpi->oxcf.arnr_max_frames - 1;
  
              cpi->source_alt_ref_pending = 1;
  
              /*
               * For alt ref frames the error score for the end frame of the
               * group (the alt ref frame) should not contribute to the group
               * total and hence the number of bit allocated to the group.
               * Rather it forms part of the next group (it is the GF at the
               * start of the next group)
               * gf_group_err -= mod_frame_err;
               *
               * For alt ref frames alt ref frame is technically part of the
               * GF frame for the next group but we always base the error
               * calculation and bit allocation on the current group of frames.
               *
               * Set the interval till the next gf or arf.
               * For ARFs this is the number of frames to be coded before the
               * future frame that is coded as an ARF.
               * The future frame itself is part of the next group
               */
              cpi->baseline_gf_interval = i;
  
              /*
               * Define the arnr filter width for this group of frames:
               * We only filter frames that lie within a distance of half
               * the GF interval from the ARF frame. We also have to trap
               * cases where the filter extends beyond the end of clip.
               * Note: this_frame->frame has been updated in the loop
               * so it now points at the ARF frame.
               */
              half_gf_int = cpi->baseline_gf_interval >> 1;
              frames_after_arf = (int)(cpi->twopass.total_stats.count -
                                 this_frame->frame - 1);
  
              switch (cpi->oxcf.arnr_type)
              {
              case 1: /* Backward filter */
                  frames_fwd = 0;
                  if (frames_bwd > half_gf_int)
                      frames_bwd = half_gf_int;
                  break;
  
              case 2: /* Forward filter */
                  if (frames_fwd > half_gf_int)
                      frames_fwd = half_gf_int;
                  if (frames_fwd > frames_after_arf)
                      frames_fwd = frames_after_arf;
                  frames_bwd = 0;
                  break;
  
              case 3: /* Centered filter */
              default:
                  frames_fwd >>= 1;
                  if (frames_fwd > frames_after_arf)
                      frames_fwd = frames_after_arf;
                  if (frames_fwd > half_gf_int)
                      frames_fwd = half_gf_int;
  
                  frames_bwd = frames_fwd;
  
                  /* For even length filter there is one more frame backward
                   * than forward: e.g. len=6 ==> bbbAff, len=7 ==> bbbAfff.
                   */
                  if (frames_bwd < half_gf_int)
                      frames_bwd += (cpi->oxcf.arnr_max_frames+1) & 0x1;
                  break;
              }
  
              cpi->active_arnr_frames = frames_bwd + 1 + frames_fwd;
          }
          else
          {
              cpi->source_alt_ref_pending = 0;
              cpi->baseline_gf_interval = i;
          }
      }
      else
      {
          cpi->source_alt_ref_pending = 0;
          cpi->baseline_gf_interval = i;
      }
  
      /*
       * Now decide how many bits should be allocated to the GF group as  a
       * proportion of those remaining in the kf group.
       * The final key frame group in the clip is treated as a special case
       * where cpi->twopass.kf_group_bits is tied to cpi->twopass.bits_left.
       * This is also important for short clips where there may only be one
       * key frame.
       */
      if (cpi->twopass.frames_to_key >= (int)(cpi->twopass.total_stats.count -
                                              cpi->common.current_video_frame))
      {
          cpi->twopass.kf_group_bits =
              (cpi->twopass.bits_left > 0) ? cpi->twopass.bits_left : 0;
      }
  
      /* Calculate the bits to be allocated to the group as a whole */
      if ((cpi->twopass.kf_group_bits > 0) &&
          (cpi->twopass.kf_group_error_left > 0))
      {
          cpi->twopass.gf_group_bits =
              (int64_t)(cpi->twopass.kf_group_bits *
                        (gf_group_err / cpi->twopass.kf_group_error_left));
      }
      else
          cpi->twopass.gf_group_bits = 0;
  
      cpi->twopass.gf_group_bits =
          (cpi->twopass.gf_group_bits < 0)
              ? 0
              : (cpi->twopass.gf_group_bits > cpi->twopass.kf_group_bits)
                  ? cpi->twopass.kf_group_bits : cpi->twopass.gf_group_bits;
  
      /* Clip cpi->twopass.gf_group_bits based on user supplied data rate
       * variability limit (cpi->oxcf.two_pass_vbrmax_section)
       */
      if (cpi->twopass.gf_group_bits >
          (int64_t)max_bits * cpi->baseline_gf_interval)
          cpi->twopass.gf_group_bits =
              (int64_t)max_bits * cpi->baseline_gf_interval;
  
      /* Reset the file position */
      reset_fpf_position(cpi, start_pos);
  
      /* Update the record of error used so far (only done once per gf group) */
      cpi->twopass.modified_error_used += gf_group_err;
  
      /* Assign  bits to the arf or gf. */
      for (i = 0; i <= (cpi->source_alt_ref_pending && cpi->common.frame_type != KEY_FRAME); i++) {
          int Boost;
          int allocation_chunks;
          int Q = (cpi->oxcf.fixed_q < 0) ? cpi->last_q[INTER_FRAME] : cpi->oxcf.fixed_q;
          int gf_bits;
  
          /* For ARF frames */
          if (cpi->source_alt_ref_pending && i == 0)
          {
  #if NEW_BOOST
              Boost = (alt_boost * GFQ_ADJUSTMENT) / 100;
  #else
              Boost = (cpi->gfu_boost * 3 * GFQ_ADJUSTMENT) / (2 * 100);
  #endif
              Boost += (cpi->baseline_gf_interval * 50);
  
              /* Set max and minimum boost and hence minimum allocation */
              if (Boost > ((cpi->baseline_gf_interval + 1) * 200))
                  Boost = ((cpi->baseline_gf_interval + 1) * 200);
              else if (Boost < 125)
                  Boost = 125;
  
              allocation_chunks =
                  ((cpi->baseline_gf_interval + 1) * 100) + Boost;
          }
          /* Else for standard golden frames */
          else
          {
              /* boost based on inter / intra ratio of subsequent frames */
              Boost = (cpi->gfu_boost * GFQ_ADJUSTMENT) / 100;
  
              /* Set max and minimum boost and hence minimum allocation */
              if (Boost > (cpi->baseline_gf_interval * 150))
                  Boost = (cpi->baseline_gf_interval * 150);
              else if (Boost < 125)
                  Boost = 125;
  
              allocation_chunks =
                  (cpi->baseline_gf_interval * 100) + (Boost - 100);
          }
  
          /* Normalize Altboost and allocations chunck down to prevent overflow */
          while (Boost > 1000)
          {
              Boost /= 2;
              allocation_chunks /= 2;
          }
  
          /* Calculate the number of bits to be spent on the gf or arf based on
           * the boost number
           */
          gf_bits = (int)((double)Boost *
                          (cpi->twopass.gf_group_bits /
                           (double)allocation_chunks));
  
          /* If the frame that is to be boosted is simpler than the average for
           * the gf/arf group then use an alternative calculation
           * based on the error score of the frame itself
           */
          if (mod_frame_err < gf_group_err / (double)cpi->baseline_gf_interval)
          {
              double  alt_gf_grp_bits;
              int     alt_gf_bits;
  
              alt_gf_grp_bits =
                  (double)cpi->twopass.kf_group_bits  *
                  (mod_frame_err * (double)cpi->baseline_gf_interval) /
                  DOUBLE_DIVIDE_CHECK((double)cpi->twopass.kf_group_error_left);
  
              alt_gf_bits = (int)((double)Boost * (alt_gf_grp_bits /
                                                   (double)allocation_chunks));
  
              if (gf_bits > alt_gf_bits)
              {
                  gf_bits = alt_gf_bits;
              }
          }
          /* Else if it is harder than other frames in the group make sure it at
           * least receives an allocation in keeping with its relative error
           * score, otherwise it may be worse off than an "un-boosted" frame
           */
          else
          {
              int alt_gf_bits =
                  (int)((double)cpi->twopass.kf_group_bits *
                        mod_frame_err /
                        DOUBLE_DIVIDE_CHECK((double)cpi->twopass.kf_group_error_left));
  
              if (alt_gf_bits > gf_bits)
              {
                  gf_bits = alt_gf_bits;
              }
          }
  
          /* Apply an additional limit for CBR */
          if (cpi->oxcf.end_usage == USAGE_STREAM_FROM_SERVER)
          {
              if (cpi->twopass.gf_bits > (int)(cpi->buffer_level >> 1))
                  cpi->twopass.gf_bits = (int)(cpi->buffer_level >> 1);
          }
  
          /* Dont allow a negative value for gf_bits */
          if (gf_bits < 0)
              gf_bits = 0;
  
          /* Add in minimum for a frame */
          gf_bits += cpi->min_frame_bandwidth;
  
          if (i == 0)
          {
              cpi->twopass.gf_bits = gf_bits;
          }
          if (i == 1 || (!cpi->source_alt_ref_pending && (cpi->common.frame_type != KEY_FRAME)))
          {
              /* Per frame bit target for this frame */
              cpi->per_frame_bandwidth = gf_bits;
          }
      }
  
      {
          /* Adjust KF group bits and error remainin */
          cpi->twopass.kf_group_error_left -= (int64_t)gf_group_err;
          cpi->twopass.kf_group_bits -= cpi->twopass.gf_group_bits;
  
          if (cpi->twopass.kf_group_bits < 0)
              cpi->twopass.kf_group_bits = 0;
  
          /* Note the error score left in the remaining frames of the group.
           * For normal GFs we want to remove the error score for the first
           * frame of the group (except in Key frame case where this has
           * already happened)
           */
          if (!cpi->source_alt_ref_pending && cpi->common.frame_type != KEY_FRAME)
              cpi->twopass.gf_group_error_left = (int)(gf_group_err -
                                                       gf_first_frame_err);
          else
              cpi->twopass.gf_group_error_left = (int) gf_group_err;
  
          cpi->twopass.gf_group_bits -= cpi->twopass.gf_bits - cpi->min_frame_bandwidth;
  
          if (cpi->twopass.gf_group_bits < 0)
              cpi->twopass.gf_group_bits = 0;
  
          /* This condition could fail if there are two kfs very close together
           * despite (MIN_GF_INTERVAL) and would cause a devide by 0 in the
           * calculation of cpi->twopass.alt_extra_bits.
           */
          if ( cpi->baseline_gf_interval >= 3 )
          {
  #if NEW_BOOST
              int boost = (cpi->source_alt_ref_pending)
                          ? b_boost : cpi->gfu_boost;
  #else
              int boost = cpi->gfu_boost;
  #endif
              if ( boost >= 150 )
              {
                  int pct_extra;
  
                  pct_extra = (boost - 100) / 50;
                  pct_extra = (pct_extra > 20) ? 20 : pct_extra;
  
                  cpi->twopass.alt_extra_bits =
                      (int)(cpi->twopass.gf_group_bits * pct_extra) / 100;
                  cpi->twopass.gf_group_bits -= cpi->twopass.alt_extra_bits;
                  cpi->twopass.alt_extra_bits /=
                      ((cpi->baseline_gf_interval-1)>>1);
              }
              else
                  cpi->twopass.alt_extra_bits = 0;
          }
          else
              cpi->twopass.alt_extra_bits = 0;
      }
  
      /* Adjustments based on a measure of complexity of the section */
      if (cpi->common.frame_type != KEY_FRAME)
      {
          FIRSTPASS_STATS sectionstats;
          double Ratio;
  
          zero_stats(&sectionstats);
          reset_fpf_position(cpi, start_pos);
  
          for (i = 0 ; i < cpi->baseline_gf_interval ; i++)
          {
              input_stats(cpi, &next_frame);
              accumulate_stats(&sectionstats, &next_frame);
          }
  
          avg_stats(&sectionstats);
  
          cpi->twopass.section_intra_rating = (unsigned int)
              (sectionstats.intra_error /
              DOUBLE_DIVIDE_CHECK(sectionstats.coded_error));
  
          Ratio = sectionstats.intra_error / DOUBLE_DIVIDE_CHECK(sectionstats.coded_error);
          cpi->twopass.section_max_qfactor = 1.0 - ((Ratio - 10.0) * 0.025);
  
          if (cpi->twopass.section_max_qfactor < 0.80)
              cpi->twopass.section_max_qfactor = 0.80;
  
          reset_fpf_position(cpi, start_pos);
      }
  }
  
  /* Allocate bits to a normal frame that is neither a gf an arf or a key frame. */
  static void assign_std_frame_bits(VP8_COMP *cpi, FIRSTPASS_STATS *this_frame)
  {
      int    target_frame_size;
  
      double modified_err;
      double err_fraction;
  
      int max_bits = frame_max_bits(cpi);  /* Max for a single frame */
  
      /* Calculate modified prediction error used in bit allocation */
      modified_err = calculate_modified_err(cpi, this_frame);
  
      /* What portion of the remaining GF group error is used by this frame */
      if (cpi->twopass.gf_group_error_left > 0)
          err_fraction = modified_err / cpi->twopass.gf_group_error_left;
      else
          err_fraction = 0.0;
  
      /* How many of those bits available for allocation should we give it? */
      target_frame_size = (int)((double)cpi->twopass.gf_group_bits * err_fraction);
  
      /* Clip to target size to 0 - max_bits (or cpi->twopass.gf_group_bits)
       * at the top end.
       */
      if (target_frame_size < 0)
          target_frame_size = 0;
      else
      {
          if (target_frame_size > max_bits)
              target_frame_size = max_bits;
  
          if (target_frame_size > cpi->twopass.gf_group_bits)
              target_frame_size = (int)cpi->twopass.gf_group_bits;
      }
  
      /* Adjust error and bits remaining */
      cpi->twopass.gf_group_error_left -= (int)modified_err;
      cpi->twopass.gf_group_bits -= target_frame_size;
  
      if (cpi->twopass.gf_group_bits < 0)
          cpi->twopass.gf_group_bits = 0;
  
      /* Add in the minimum number of bits that is set aside for every frame. */
      target_frame_size += cpi->min_frame_bandwidth;
  
      /* Every other frame gets a few extra bits */
      if ( (cpi->frames_since_golden & 0x01) &&
           (cpi->frames_till_gf_update_due > 0) )
      {
          target_frame_size += cpi->twopass.alt_extra_bits;
      }
  
      /* Per frame bit target for this frame */
      cpi->per_frame_bandwidth = target_frame_size;
  }
  
  void vp8_second_pass(VP8_COMP *cpi)
  {
      int tmp_q;
      int frames_left = (int)(cpi->twopass.total_stats.count - cpi->common.current_video_frame);
  
      FIRSTPASS_STATS this_frame;
      FIRSTPASS_STATS this_frame_copy;
  
      double this_frame_intra_error;
      double this_frame_coded_error;
  
      int overhead_bits;
  
      memset(&this_frame, 0, sizeof(FIRSTPASS_STATS));
      if (!cpi->twopass.stats_in)
      {
          return ;
      }
  
      vp8_clear_system_state();
  
      if (EOF == input_stats(cpi, &this_frame))
          return;
  
      this_frame_intra_error = this_frame.intra_error;
      this_frame_coded_error = this_frame.coded_error;
  
      /* keyframe and section processing ! */
      if (cpi->twopass.frames_to_key == 0)
      {
          /* Define next KF group and assign bits to it */
          vpx_memcpy(&this_frame_copy, &this_frame, sizeof(this_frame));
          find_next_key_frame(cpi, &this_frame_copy);
  
          /* Special case: Error error_resilient_mode mode does not make much
           * sense for two pass but with its current meaning this code is
           * designed to stop outlandish behaviour if someone does set it when
           * using two pass. It effectively disables GF groups. This is
           * temporary code until we decide what should really happen in this
           * case.
           */
          if (cpi->oxcf.error_resilient_mode)
          {
              cpi->twopass.gf_group_bits = cpi->twopass.kf_group_bits;
              cpi->twopass.gf_group_error_left =
                                    (int)cpi->twopass.kf_group_error_left;
              cpi->baseline_gf_interval = cpi->twopass.frames_to_key;
              cpi->frames_till_gf_update_due = cpi->baseline_gf_interval;
              cpi->source_alt_ref_pending = 0;
          }
  
      }
  
      /* Is this a GF / ARF (Note that a KF is always also a GF) */
      if (cpi->frames_till_gf_update_due == 0)
      {
          /* Define next gf group and assign bits to it */
          vpx_memcpy(&this_frame_copy, &this_frame, sizeof(this_frame));
          define_gf_group(cpi, &this_frame_copy);
  
          /* If we are going to code an altref frame at the end of the group
           * and the current frame is not a key frame.... If the previous
           * group used an arf this frame has already benefited from that arf
           * boost and it should not be given extra bits If the previous
           * group was NOT coded using arf we may want to apply some boost to
           * this GF as well
           */
          if (cpi->source_alt_ref_pending && (cpi->common.frame_type != KEY_FRAME))
          {
              /* Assign a standard frames worth of bits from those allocated
               * to the GF group
               */
              int bak = cpi->per_frame_bandwidth;
              vpx_memcpy(&this_frame_copy, &this_frame, sizeof(this_frame));
              assign_std_frame_bits(cpi, &this_frame_copy);
              cpi->per_frame_bandwidth = bak;
          }
      }
  
      /* Otherwise this is an ordinary frame */
      else
      {
          /* Special case: Error error_resilient_mode mode does not make much
           * sense for two pass but with its current meaning but this code is
           * designed to stop outlandish behaviour if someone does set it
           * when using two pass. It effectively disables GF groups. This is
           * temporary code till we decide what should really happen in this
           * case.
           */
          if (cpi->oxcf.error_resilient_mode)
          {
              cpi->frames_till_gf_update_due = cpi->twopass.frames_to_key;
  
              if (cpi->common.frame_type != KEY_FRAME)
              {
                  /* Assign bits from those allocated to the GF group */
                  vpx_memcpy(&this_frame_copy, &this_frame, sizeof(this_frame));
                  assign_std_frame_bits(cpi, &this_frame_copy);
              }
          }
          else
          {
              /* Assign bits from those allocated to the GF group */
              vpx_memcpy(&this_frame_copy, &this_frame, sizeof(this_frame));
              assign_std_frame_bits(cpi, &this_frame_copy);
          }
      }
  
      /* Keep a globally available copy of this and the next frame's iiratio. */
      cpi->twopass.this_iiratio = (unsigned int)(this_frame_intra_error /
                          DOUBLE_DIVIDE_CHECK(this_frame_coded_error));
      {
          FIRSTPASS_STATS next_frame;
          if ( lookup_next_frame_stats(cpi, &next_frame) != EOF )
          {
              cpi->twopass.next_iiratio = (unsigned int)(next_frame.intra_error /
                                  DOUBLE_DIVIDE_CHECK(next_frame.coded_error));
          }
      }
  
      /* Set nominal per second bandwidth for this frame */
      cpi->target_bandwidth = (int)
      (cpi->per_frame_bandwidth * cpi->output_framerate);
      if (cpi->target_bandwidth < 0)
          cpi->target_bandwidth = 0;
  
  
      /* Account for mv, mode and other overheads. */
      overhead_bits = (int)estimate_modemvcost(
                          cpi, &cpi->twopass.total_left_stats );
  
      /* Special case code for first frame. */
      if (cpi->common.current_video_frame == 0)
      {
          cpi->twopass.est_max_qcorrection_factor = 1.0;
  
          /* Set a cq_level in constrained quality mode. */
          if ( cpi->oxcf.end_usage == USAGE_CONSTRAINED_QUALITY )
          {
              int est_cq;
  
              est_cq =
                  estimate_cq( cpi,
                               &cpi->twopass.total_left_stats,
                               (int)(cpi->twopass.bits_left / frames_left),
                               overhead_bits );
  
              cpi->cq_target_quality = cpi->oxcf.cq_level;
              if ( est_cq > cpi->cq_target_quality )
                  cpi->cq_target_quality = est_cq;
          }
  
          /* guess at maxq needed in 2nd pass */
          cpi->twopass.maxq_max_limit = cpi->worst_quality;
          cpi->twopass.maxq_min_limit = cpi->best_quality;
  
          tmp_q = estimate_max_q(
                      cpi,
                      &cpi->twopass.total_left_stats,
                      (int)(cpi->twopass.bits_left / frames_left),
                      overhead_bits );
  
          /* Limit the maxq value returned subsequently.
           * This increases the risk of overspend or underspend if the initial
           * estimate for the clip is bad, but helps prevent excessive
           * variation in Q, especially near the end of a clip
           * where for example a small overspend may cause Q to crash
           */
          cpi->twopass.maxq_max_limit = ((tmp_q + 32) < cpi->worst_quality)
                                    ? (tmp_q + 32) : cpi->worst_quality;
          cpi->twopass.maxq_min_limit = ((tmp_q - 32) > cpi->best_quality)
                                    ? (tmp_q - 32) : cpi->best_quality;
  
          cpi->active_worst_quality         = tmp_q;
          cpi->ni_av_qi                     = tmp_q;
      }
  
      /* The last few frames of a clip almost always have to few or too many
       * bits and for the sake of over exact rate control we dont want to make
       * radical adjustments to the allowed quantizer range just to use up a
       * few surplus bits or get beneath the target rate.
       */
      else if ( (cpi->common.current_video_frame <
                   (((unsigned int)cpi->twopass.total_stats.count * 255)>>8)) &&
                ((cpi->common.current_video_frame + cpi->baseline_gf_interval) <
                   (unsigned int)cpi->twopass.total_stats.count) )
      {
          if (frames_left < 1)
              frames_left = 1;
  
          tmp_q = estimate_max_q(
                      cpi,
                      &cpi->twopass.total_left_stats,
                      (int)(cpi->twopass.bits_left / frames_left),
                      overhead_bits );
  
          /* Move active_worst_quality but in a damped way */
          if (tmp_q > cpi->active_worst_quality)
              cpi->active_worst_quality ++;
          else if (tmp_q < cpi->active_worst_quality)
              cpi->active_worst_quality --;
  
          cpi->active_worst_quality =
              ((cpi->active_worst_quality * 3) + tmp_q + 2) / 4;
      }
  
      cpi->twopass.frames_to_key --;
  
      /* Update the total stats remaining sturcture */
      subtract_stats(&cpi->twopass.total_left_stats, &this_frame );
  }
  
  
  static int test_candidate_kf(VP8_COMP *cpi,  FIRSTPASS_STATS *last_frame, FIRSTPASS_STATS *this_frame, FIRSTPASS_STATS *next_frame)
  {
      int is_viable_kf = 0;
  
      /* Does the frame satisfy the primary criteria of a key frame
       *      If so, then examine how well it predicts subsequent frames
       */
      if ((this_frame->pcnt_second_ref < 0.10) &&
          (next_frame->pcnt_second_ref < 0.10) &&
          ((this_frame->pcnt_inter < 0.05) ||
           (
               ((this_frame->pcnt_inter - this_frame->pcnt_neutral) < .25) &&
               ((this_frame->intra_error / DOUBLE_DIVIDE_CHECK(this_frame->coded_error)) < 2.5) &&
               ((fabs(last_frame->coded_error - this_frame->coded_error) / DOUBLE_DIVIDE_CHECK(this_frame->coded_error) > .40) ||
                (fabs(last_frame->intra_error - this_frame->intra_error) / DOUBLE_DIVIDE_CHECK(this_frame->intra_error) > .40) ||
                ((next_frame->intra_error / DOUBLE_DIVIDE_CHECK(next_frame->coded_error)) > 3.5)
               )
           )
          )
         )
      {
          int i;
          FIRSTPASS_STATS *start_pos;
  
          FIRSTPASS_STATS local_next_frame;
  
          double boost_score = 0.0;
          double old_boost_score = 0.0;
          double decay_accumulator = 1.0;
          double next_iiratio;
  
          vpx_memcpy(&local_next_frame, next_frame, sizeof(*next_frame));
  
          /* Note the starting file position so we can reset to it */
          start_pos = cpi->twopass.stats_in;
  
          /* Examine how well the key frame predicts subsequent frames */
          for (i = 0 ; i < 16; i++)
          {
              next_iiratio = (IIKFACTOR1 * local_next_frame.intra_error / DOUBLE_DIVIDE_CHECK(local_next_frame.coded_error)) ;
  
              if (next_iiratio > RMAX)
                  next_iiratio = RMAX;
  
              /* Cumulative effect of decay in prediction quality */
              if (local_next_frame.pcnt_inter > 0.85)
                  decay_accumulator = decay_accumulator * local_next_frame.pcnt_inter;
              else
                  decay_accumulator = decay_accumulator * ((0.85 + local_next_frame.pcnt_inter) / 2.0);
  
              /* Keep a running total */
              boost_score += (decay_accumulator * next_iiratio);
  
              /* Test various breakout clauses */
              if ((local_next_frame.pcnt_inter < 0.05) ||
                  (next_iiratio < 1.5) ||
                  (((local_next_frame.pcnt_inter -
                     local_next_frame.pcnt_neutral) < 0.20) &&
                   (next_iiratio < 3.0)) ||
                  ((boost_score - old_boost_score) < 0.5) ||
                  (local_next_frame.intra_error < 200)
                 )
              {
                  break;
              }
  
              old_boost_score = boost_score;
  
              /* Get the next frame details */
              if (EOF == input_stats(cpi, &local_next_frame))
                  break;
          }
  
          /* If there is tolerable prediction for at least the next 3 frames
           * then break out else discard this pottential key frame and move on
           */
          if (boost_score > 5.0 && (i > 3))
              is_viable_kf = 1;
          else
          {
              /* Reset the file position */
              reset_fpf_position(cpi, start_pos);
  
              is_viable_kf = 0;
          }
      }
  
      return is_viable_kf;
  }
  static void find_next_key_frame(VP8_COMP *cpi, FIRSTPASS_STATS *this_frame)
  {
      int i,j;
      FIRSTPASS_STATS last_frame;
      FIRSTPASS_STATS first_frame;
      FIRSTPASS_STATS next_frame;
      FIRSTPASS_STATS *start_position;
  
      double decay_accumulator = 1.0;
      double boost_score = 0;
      double old_boost_score = 0.0;
      double loop_decay_rate;
  
      double kf_mod_err = 0.0;
      double kf_group_err = 0.0;
      double kf_group_intra_err = 0.0;
      double kf_group_coded_err = 0.0;
      double recent_loop_decay[8] = {1.0,1.0,1.0,1.0,1.0,1.0,1.0,1.0};
  
      vpx_memset(&next_frame, 0, sizeof(next_frame));
  
      vp8_clear_system_state();
      start_position = cpi->twopass.stats_in;
  
      cpi->common.frame_type = KEY_FRAME;
  
      /* is this a forced key frame by interval */
      cpi->this_key_frame_forced = cpi->next_key_frame_forced;
  
      /* Clear the alt ref active flag as this can never be active on a key
       * frame
       */
      cpi->source_alt_ref_active = 0;
  
      /* Kf is always a gf so clear frames till next gf counter */
      cpi->frames_till_gf_update_due = 0;
  
      cpi->twopass.frames_to_key = 1;
  
      /* Take a copy of the initial frame details */
      vpx_memcpy(&first_frame, this_frame, sizeof(*this_frame));
  
      cpi->twopass.kf_group_bits = 0;
      cpi->twopass.kf_group_error_left = 0;
  
      kf_mod_err = calculate_modified_err(cpi, this_frame);
  
      /* find the next keyframe */
      i = 0;
      while (cpi->twopass.stats_in < cpi->twopass.stats_in_end)
      {
          /* Accumulate kf group error */
          kf_group_err += calculate_modified_err(cpi, this_frame);
  
          /* These figures keep intra and coded error counts for all frames
           * including key frames in the group. The effect of the key frame
           * itself can be subtracted out using the first_frame data
           * collected above
           */
          kf_group_intra_err += this_frame->intra_error;
          kf_group_coded_err += this_frame->coded_error;
  
          /* Load the next frame's stats. */
          vpx_memcpy(&last_frame, this_frame, sizeof(*this_frame));
          input_stats(cpi, this_frame);
  
          /* Provided that we are not at the end of the file... */
          if (cpi->oxcf.auto_key
              && lookup_next_frame_stats(cpi, &next_frame) != EOF)
          {
              /* Normal scene cut check */
              if ( ( i >= MIN_GF_INTERVAL ) &&
                   test_candidate_kf(cpi, &last_frame, this_frame, &next_frame) )
              {
                  break;
              }
  
              /* How fast is prediction quality decaying */
              loop_decay_rate = get_prediction_decay_rate(cpi, &next_frame);
  
              /* We want to know something about the recent past... rather than
               * as used elsewhere where we are concened with decay in prediction
               * quality since the last GF or KF.
               */
              recent_loop_decay[i%8] = loop_decay_rate;
              decay_accumulator = 1.0;
              for (j = 0; j < 8; j++)
              {
                  decay_accumulator = decay_accumulator * recent_loop_decay[j];
              }
  
              /* Special check for transition or high motion followed by a
               * static scene.
               */
              if ( detect_transition_to_still( cpi, i,
                                               (cpi->key_frame_frequency-i),
                                               loop_decay_rate,
                                               decay_accumulator ) )
              {
                  break;
              }
  
  
              /* Step on to the next frame */
              cpi->twopass.frames_to_key ++;
  
              /* If we don't have a real key frame within the next two
               * forcekeyframeevery intervals then break out of the loop.
               */
              if (cpi->twopass.frames_to_key >= 2 *(int)cpi->key_frame_frequency)
                  break;
          } else
              cpi->twopass.frames_to_key ++;
  
          i++;
      }
  
      /* If there is a max kf interval set by the user we must obey it.
       * We already breakout of the loop above at 2x max.
       * This code centers the extra kf if the actual natural
       * interval is between 1x and 2x
       */
      if (cpi->oxcf.auto_key
          && cpi->twopass.frames_to_key > (int)cpi->key_frame_frequency )
      {
          FIRSTPASS_STATS *current_pos = cpi->twopass.stats_in;
          FIRSTPASS_STATS tmp_frame;
  
          cpi->twopass.frames_to_key /= 2;
  
          /* Copy first frame details */
          vpx_memcpy(&tmp_frame, &first_frame, sizeof(first_frame));
  
          /* Reset to the start of the group */
          reset_fpf_position(cpi, start_position);
  
          kf_group_err = 0;
          kf_group_intra_err = 0;
          kf_group_coded_err = 0;
  
          /* Rescan to get the correct error data for the forced kf group */
          for( i = 0; i < cpi->twopass.frames_to_key; i++ )
          {
              /* Accumulate kf group errors */
              kf_group_err += calculate_modified_err(cpi, &tmp_frame);
              kf_group_intra_err += tmp_frame.intra_error;
              kf_group_coded_err += tmp_frame.coded_error;
  
              /* Load a the next frame's stats */
              input_stats(cpi, &tmp_frame);
          }
  
          /* Reset to the start of the group */
          reset_fpf_position(cpi, current_pos);
  
          cpi->next_key_frame_forced = 1;
      }
      else
          cpi->next_key_frame_forced = 0;
  
      /* Special case for the last frame of the file */
      if (cpi->twopass.stats_in >= cpi->twopass.stats_in_end)
      {
          /* Accumulate kf group error */
          kf_group_err += calculate_modified_err(cpi, this_frame);
  
          /* These figures keep intra and coded error counts for all frames
           * including key frames in the group. The effect of the key frame
           * itself can be subtracted out using the first_frame data
           * collected above
           */
          kf_group_intra_err += this_frame->intra_error;
          kf_group_coded_err += this_frame->coded_error;
      }
  
      /* Calculate the number of bits that should be assigned to the kf group. */
      if ((cpi->twopass.bits_left > 0) && (cpi->twopass.modified_error_left > 0.0))
      {
          /* Max for a single normal frame (not key frame) */
          int max_bits = frame_max_bits(cpi);
  
          /* Maximum bits for the kf group */
          int64_t max_grp_bits;
  
          /* Default allocation based on bits left and relative
           * complexity of the section
           */
          cpi->twopass.kf_group_bits = (int64_t)( cpi->twopass.bits_left *
                                            ( kf_group_err /
                                              cpi->twopass.modified_error_left ));
  
          /* Clip based on maximum per frame rate defined by the user. */
          max_grp_bits = (int64_t)max_bits * (int64_t)cpi->twopass.frames_to_key;
          if (cpi->twopass.kf_group_bits > max_grp_bits)
              cpi->twopass.kf_group_bits = max_grp_bits;
  
          /* Additional special case for CBR if buffer is getting full. */
          if (cpi->oxcf.end_usage == USAGE_STREAM_FROM_SERVER)
          {
              int64_t opt_buffer_lvl = cpi->oxcf.optimal_buffer_level;
              int64_t buffer_lvl = cpi->buffer_level;
  
              /* If the buffer is near or above the optimal and this kf group is
               * not being allocated much then increase the allocation a bit.
               */
              if (buffer_lvl >= opt_buffer_lvl)
              {
                  int64_t high_water_mark = (opt_buffer_lvl +
                                         cpi->oxcf.maximum_buffer_size) >> 1;
  
                  int64_t av_group_bits;
  
                  /* Av bits per frame * number of frames */
                  av_group_bits = (int64_t)cpi->av_per_frame_bandwidth *
                                  (int64_t)cpi->twopass.frames_to_key;
  
                  /* We are at or above the maximum. */
                  if (cpi->buffer_level >= high_water_mark)
                  {
                      int64_t min_group_bits;
  
                      min_group_bits = av_group_bits +
                                       (int64_t)(buffer_lvl -
                                                   high_water_mark);
  
                      if (cpi->twopass.kf_group_bits < min_group_bits)
                          cpi->twopass.kf_group_bits = min_group_bits;
                  }
                  /* We are above optimal but below the maximum */
                  else if (cpi->twopass.kf_group_bits < av_group_bits)
                  {
                      int64_t bits_below_av = av_group_bits -
                                                cpi->twopass.kf_group_bits;
  
                      cpi->twopass.kf_group_bits +=
                         (int64_t)((double)bits_below_av *
                                     (double)(buffer_lvl - opt_buffer_lvl) /
                                     (double)(high_water_mark - opt_buffer_lvl));
                  }
              }
          }
      }
      else
          cpi->twopass.kf_group_bits = 0;
  
      /* Reset the first pass file position */
      reset_fpf_position(cpi, start_position);
  
      /* determine how big to make this keyframe based on how well the
       * subsequent frames use inter blocks
       */
      decay_accumulator = 1.0;
      boost_score = 0.0;
      loop_decay_rate = 1.00;       /* Starting decay rate */
  
      for (i = 0 ; i < cpi->twopass.frames_to_key ; i++)
      {
          double r;
  
          if (EOF == input_stats(cpi, &next_frame))
              break;
  
          if (next_frame.intra_error > cpi->twopass.kf_intra_err_min)
              r = (IIKFACTOR2 * next_frame.intra_error /
                       DOUBLE_DIVIDE_CHECK(next_frame.coded_error));
          else
              r = (IIKFACTOR2 * cpi->twopass.kf_intra_err_min /
                       DOUBLE_DIVIDE_CHECK(next_frame.coded_error));
  
          if (r > RMAX)
              r = RMAX;
  
          /* How fast is prediction quality decaying */
          loop_decay_rate = get_prediction_decay_rate(cpi, &next_frame);
  
          decay_accumulator = decay_accumulator * loop_decay_rate;
          decay_accumulator = decay_accumulator < 0.1 ? 0.1 : decay_accumulator;
  
          boost_score += (decay_accumulator * r);
  
          if ((i > MIN_GF_INTERVAL) &&
              ((boost_score - old_boost_score) < 1.0))
          {
              break;
          }
  
          old_boost_score = boost_score;
      }
  
      if (1)
      {
          FIRSTPASS_STATS sectionstats;
          double Ratio;
  
          zero_stats(&sectionstats);
          reset_fpf_position(cpi, start_position);
  
          for (i = 0 ; i < cpi->twopass.frames_to_key ; i++)
          {
              input_stats(cpi, &next_frame);
              accumulate_stats(&sectionstats, &next_frame);
          }
  
          avg_stats(&sectionstats);
  
          cpi->twopass.section_intra_rating = (unsigned int)
              (sectionstats.intra_error
              / DOUBLE_DIVIDE_CHECK(sectionstats.coded_error));
  
          Ratio = sectionstats.intra_error / DOUBLE_DIVIDE_CHECK(sectionstats.coded_error);
          cpi->twopass.section_max_qfactor = 1.0 - ((Ratio - 10.0) * 0.025);
  
          if (cpi->twopass.section_max_qfactor < 0.80)
              cpi->twopass.section_max_qfactor = 0.80;
      }
  
      /* When using CBR apply additional buffer fullness related upper limits */
      if (cpi->oxcf.end_usage == USAGE_STREAM_FROM_SERVER)
      {
          double max_boost;
  
          if (cpi->drop_frames_allowed)
          {
              int df_buffer_level = (int)(cpi->oxcf.drop_frames_water_mark
                                    * (cpi->oxcf.optimal_buffer_level / 100));
  
              if (cpi->buffer_level > df_buffer_level)
                  max_boost = ((double)((cpi->buffer_level - df_buffer_level) * 2 / 3) * 16.0) / DOUBLE_DIVIDE_CHECK((double)cpi->av_per_frame_bandwidth);
              else
                  max_boost = 0.0;
          }
          else if (cpi->buffer_level > 0)
          {
              max_boost = ((double)(cpi->buffer_level * 2 / 3) * 16.0) / DOUBLE_DIVIDE_CHECK((double)cpi->av_per_frame_bandwidth);
          }
          else
          {
              max_boost = 0.0;
          }
  
          if (boost_score > max_boost)
              boost_score = max_boost;
      }
  
      /* Reset the first pass file position */
      reset_fpf_position(cpi, start_position);
  
      /* Work out how many bits to allocate for the key frame itself */
      if (1)
      {
          int kf_boost = (int)boost_score;
          int allocation_chunks;
          int Counter = cpi->twopass.frames_to_key;
          int alt_kf_bits;
          YV12_BUFFER_CONFIG *lst_yv12 = &cpi->common.yv12_fb[cpi->common.lst_fb_idx];
          /* Min boost based on kf interval */
  #if 0
  
          while ((kf_boost < 48) && (Counter > 0))
          {
              Counter -= 2;
              kf_boost ++;
          }
  
  #endif
  
          if (kf_boost < 48)
          {
              kf_boost += ((Counter + 1) >> 1);
  
              if (kf_boost > 48) kf_boost = 48;
          }
  
          /* bigger frame sizes need larger kf boosts, smaller frames smaller
           * boosts...
           */
          if ((lst_yv12->y_width * lst_yv12->y_height) > (320 * 240))
              kf_boost += 2 * (lst_yv12->y_width * lst_yv12->y_height) / (320 * 240);
          else if ((lst_yv12->y_width * lst_yv12->y_height) < (320 * 240))
              kf_boost -= 4 * (320 * 240) / (lst_yv12->y_width * lst_yv12->y_height);
  
          /* Min KF boost */
          kf_boost = (int)((double)kf_boost * 100.0) >> 4; /* Scale 16 to 100 */
          if (kf_boost < 250)
              kf_boost = 250;
  
          /*
           * We do three calculations for kf size.
           * The first is based on the error score for the whole kf group.
           * The second (optionaly) on the key frames own error if this is
           * smaller than the average for the group.
           * The final one insures that the frame receives at least the
           * allocation it would have received based on its own error score vs
           * the error score remaining
           * Special case if the sequence appears almost totaly static
           * as measured by the decay accumulator. In this case we want to
           * spend almost all of the bits on the key frame.
           * cpi->twopass.frames_to_key-1 because key frame itself is taken
           * care of by kf_boost.
           */
          if ( decay_accumulator >= 0.99 )
          {
              allocation_chunks =
                  ((cpi->twopass.frames_to_key - 1) * 10) + kf_boost;
          }
          else
          {
              allocation_chunks =
                  ((cpi->twopass.frames_to_key - 1) * 100) + kf_boost;
          }
  
          /* Normalize Altboost and allocations chunck down to prevent overflow */
          while (kf_boost > 1000)
          {
              kf_boost /= 2;
              allocation_chunks /= 2;
          }
  
          cpi->twopass.kf_group_bits = (cpi->twopass.kf_group_bits < 0) ? 0 : cpi->twopass.kf_group_bits;
  
          /* Calculate the number of bits to be spent on the key frame */
          cpi->twopass.kf_bits  = (int)((double)kf_boost * ((double)cpi->twopass.kf_group_bits / (double)allocation_chunks));
  
          /* Apply an additional limit for CBR */
          if (cpi->oxcf.end_usage == USAGE_STREAM_FROM_SERVER)
          {
              if (cpi->twopass.kf_bits > (int)((3 * cpi->buffer_level) >> 2))
                  cpi->twopass.kf_bits = (int)((3 * cpi->buffer_level) >> 2);
          }
  
          /* If the key frame is actually easier than the average for the
           * kf group (which does sometimes happen... eg a blank intro frame)
           * Then use an alternate calculation based on the kf error score
           * which should give a smaller key frame.
           */
          if (kf_mod_err < kf_group_err / cpi->twopass.frames_to_key)
          {
              double  alt_kf_grp_bits =
                          ((double)cpi->twopass.bits_left *
                           (kf_mod_err * (double)cpi->twopass.frames_to_key) /
                           DOUBLE_DIVIDE_CHECK(cpi->twopass.modified_error_left));
  
              alt_kf_bits = (int)((double)kf_boost *
                                  (alt_kf_grp_bits / (double)allocation_chunks));
  
              if (cpi->twopass.kf_bits > alt_kf_bits)
              {
                  cpi->twopass.kf_bits = alt_kf_bits;
              }
          }
          /* Else if it is much harder than other frames in the group make sure
           * it at least receives an allocation in keeping with its relative
           * error score
           */
          else
          {
              alt_kf_bits =
                  (int)((double)cpi->twopass.bits_left *
                        (kf_mod_err /
                         DOUBLE_DIVIDE_CHECK(cpi->twopass.modified_error_left)));
  
              if (alt_kf_bits > cpi->twopass.kf_bits)
              {
                  cpi->twopass.kf_bits = alt_kf_bits;
              }
          }
  
          cpi->twopass.kf_group_bits -= cpi->twopass.kf_bits;
          /* Add in the minimum frame allowance */
          cpi->twopass.kf_bits += cpi->min_frame_bandwidth;
  
          /* Peer frame bit target for this frame */
          cpi->per_frame_bandwidth = cpi->twopass.kf_bits;
  
          /* Convert to a per second bitrate */
          cpi->target_bandwidth = (int)(cpi->twopass.kf_bits *
                                        cpi->output_framerate);
      }
  
      /* Note the total error score of the kf group minus the key frame itself */
      cpi->twopass.kf_group_error_left = (int)(kf_group_err - kf_mod_err);
  
      /* Adjust the count of total modified error left. The count of bits left
       * is adjusted elsewhere based on real coded frame sizes
       */
      cpi->twopass.modified_error_left -= kf_group_err;
  
      if (cpi->oxcf.allow_spatial_resampling)
      {
          int resample_trigger = 0;
          int last_kf_resampled = 0;
          int kf_q;
          int scale_val = 0;
          int hr, hs, vr, vs;
          int new_width = cpi->oxcf.Width;
          int new_height = cpi->oxcf.Height;
  
          int projected_buffer_level = (int)cpi->buffer_level;
          int tmp_q;
  
          double projected_bits_perframe;
          double group_iiratio = (kf_group_intra_err - first_frame.intra_error) / (kf_group_coded_err - first_frame.coded_error);
          double err_per_frame = kf_group_err / cpi->twopass.frames_to_key;
          double bits_per_frame;
          double av_bits_per_frame;
          double effective_size_ratio;
  
          if ((cpi->common.Width != cpi->oxcf.Width) || (cpi->common.Height != cpi->oxcf.Height))
              last_kf_resampled = 1;
  
          /* Set back to unscaled by defaults */
          cpi->common.horiz_scale = NORMAL;
          cpi->common.vert_scale = NORMAL;
  
          /* Calculate Average bits per frame. */
          av_bits_per_frame = cpi->oxcf.target_bandwidth / DOUBLE_DIVIDE_CHECK((double)cpi->framerate);
  
          /* CBR... Use the clip average as the target for deciding resample */
          if (cpi->oxcf.end_usage == USAGE_STREAM_FROM_SERVER)
          {
              bits_per_frame = av_bits_per_frame;
          }
  
          /* In VBR we want to avoid downsampling in easy section unless we
           * are under extreme pressure So use the larger of target bitrate
           * for this section or average bitrate for sequence
           */
          else
          {
              /* This accounts for how hard the section is... */
              bits_per_frame = (double)
                  (cpi->twopass.kf_group_bits / cpi->twopass.frames_to_key);
  
              /* Dont turn to resampling in easy sections just because they
               * have been assigned a small number of bits
               */
              if (bits_per_frame < av_bits_per_frame)
                  bits_per_frame = av_bits_per_frame;
          }
  
          /* bits_per_frame should comply with our minimum */
          if (bits_per_frame < (cpi->oxcf.target_bandwidth * cpi->oxcf.two_pass_vbrmin_section / 100))
              bits_per_frame = (cpi->oxcf.target_bandwidth * cpi->oxcf.two_pass_vbrmin_section / 100);
  
          /* Work out if spatial resampling is necessary */
          kf_q = estimate_kf_group_q(cpi, err_per_frame,
                                    (int)bits_per_frame, group_iiratio);
  
          /* If we project a required Q higher than the maximum allowed Q then
           * make a guess at the actual size of frames in this section
           */
          projected_bits_perframe = bits_per_frame;
          tmp_q = kf_q;
  
          while (tmp_q > cpi->worst_quality)
          {
              projected_bits_perframe *= 1.04;
              tmp_q--;
          }
  
          /* Guess at buffer level at the end of the section */
          projected_buffer_level = (int)
                      (cpi->buffer_level - (int)
                      ((projected_bits_perframe - av_bits_per_frame) *
                      cpi->twopass.frames_to_key));
  
          if (0)
          {
              FILE *f = fopen("Subsamle.stt", "a");
              fprintf(f, " %8d %8d %8d %8d %12.0f %8d %8d %8d\n",  cpi->common.current_video_frame, kf_q, cpi->common.horiz_scale, cpi->common.vert_scale,  kf_group_err / cpi->twopass.frames_to_key, (int)(cpi->twopass.kf_group_bits / cpi->twopass.frames_to_key), new_height, new_width);
              fclose(f);
          }
  
          /* The trigger for spatial resampling depends on the various
           * parameters such as whether we are streaming (CBR) or VBR.
           */
          if (cpi->oxcf.end_usage == USAGE_STREAM_FROM_SERVER)
          {
              /* Trigger resample if we are projected to fall below down
               * sample level or resampled last time and are projected to
               * remain below the up sample level
               */
              if ((projected_buffer_level < (cpi->oxcf.resample_down_water_mark * cpi->oxcf.optimal_buffer_level / 100)) ||
                  (last_kf_resampled && (projected_buffer_level < (cpi->oxcf.resample_up_water_mark * cpi->oxcf.optimal_buffer_level / 100))))
                  resample_trigger = 1;
              else
                  resample_trigger = 0;
          }
          else
          {
              int64_t clip_bits = (int64_t)(cpi->twopass.total_stats.count * cpi->oxcf.target_bandwidth / DOUBLE_DIVIDE_CHECK((double)cpi->framerate));
              int64_t over_spend = cpi->oxcf.starting_buffer_level - cpi->buffer_level;
  
              /* If triggered last time the threshold for triggering again is
               * reduced:
               *
               * Projected Q higher than allowed and Overspend > 5% of total
               * bits
               */
              if ((last_kf_resampled && (kf_q > cpi->worst_quality)) ||
                  ((kf_q > cpi->worst_quality) &&
                   (over_spend > clip_bits / 20)))
                  resample_trigger = 1;
              else
                  resample_trigger = 0;
  
          }
  
          if (resample_trigger)
          {
              while ((kf_q >= cpi->worst_quality) && (scale_val < 6))
              {
                  scale_val ++;
  
                  cpi->common.vert_scale   = vscale_lookup[scale_val];
                  cpi->common.horiz_scale  = hscale_lookup[scale_val];
  
                  Scale2Ratio(cpi->common.horiz_scale, &hr, &hs);
                  Scale2Ratio(cpi->common.vert_scale, &vr, &vs);
  
                  new_width = ((hs - 1) + (cpi->oxcf.Width * hr)) / hs;
                  new_height = ((vs - 1) + (cpi->oxcf.Height * vr)) / vs;
  
                  /* Reducing the area to 1/4 does not reduce the complexity
                   * (err_per_frame) to 1/4... effective_sizeratio attempts
                   * to provide a crude correction for this
                   */
                  effective_size_ratio = (double)(new_width * new_height) / (double)(cpi->oxcf.Width * cpi->oxcf.Height);
                  effective_size_ratio = (1.0 + (3.0 * effective_size_ratio)) / 4.0;
  
                  /* Now try again and see what Q we get with the smaller
                   * image size
                   */
                  kf_q = estimate_kf_group_q(cpi,
                                            err_per_frame * effective_size_ratio,
                                            (int)bits_per_frame, group_iiratio);
  
                  if (0)
                  {
                      FILE *f = fopen("Subsamle.stt", "a");
                      fprintf(f, "******** %8d %8d %8d %12.0f %8d %8d %8d\n",  kf_q, cpi->common.horiz_scale, cpi->common.vert_scale,  kf_group_err / cpi->twopass.frames_to_key, (int)(cpi->twopass.kf_group_bits / cpi->twopass.frames_to_key), new_height, new_width);
                      fclose(f);
                  }
              }
          }
  
          if ((cpi->common.Width != new_width) || (cpi->common.Height != new_height))
          {
              cpi->common.Width = new_width;
              cpi->common.Height = new_height;
              vp8_alloc_compressor_data(cpi);
          }
      }
  }
  