text: /*
   * H.26L/H.264/AVC/JVT/14496-10/... decoder
   * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
   *
   * This file is part of FFmpeg.
   *
   * FFmpeg is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * FFmpeg is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with FFmpeg; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
   */
  
  /**
   * @file
   * H.264 / AVC / MPEG4 part10 codec.
   * @author Michael Niedermayer <michaelni@gmx.at>
   */
  
  #define UNCHECKED_BITSTREAM_READER 1
  
  #include "libavutil/avassert.h"
  #include "libavutil/display.h"
  #include "libavutil/imgutils.h"
  #include "libavutil/opt.h"
  #include "libavutil/stereo3d.h"
  #include "libavutil/timer.h"
  #include "internal.h"
  #include "cabac.h"
  #include "cabac_functions.h"
  #include "error_resilience.h"
  #include "avcodec.h"
  #include "h264.h"
  #include "h264data.h"
  #include "h264chroma.h"
  #include "h264_mvpred.h"
  #include "golomb.h"
  #include "mathops.h"
  #include "me_cmp.h"
  #include "mpegutils.h"
  #include "rectangle.h"
  #include "svq3.h"
  #include "thread.h"
  #include "vdpau_compat.h"
  
  const uint16_t ff_h264_mb_sizes[4] = { 256, 384, 512, 768 };
  
  int avpriv_h264_has_num_reorder_frames(AVCodecContext *avctx)
  {
      H264Context *h = avctx->priv_data;
      return h ? h->sps.num_reorder_frames : 0;
  }
  
  static void h264_er_decode_mb(void *opaque, int ref, int mv_dir, int mv_type,
                                int (*mv)[2][4][2],
                                int mb_x, int mb_y, int mb_intra, int mb_skipped)
  {
      H264Context *h = opaque;
      H264SliceContext *sl = &h->slice_ctx[0];
  
      sl->mb_x = mb_x;
      sl->mb_y = mb_y;
      sl->mb_xy = mb_x + mb_y * h->mb_stride;
      memset(sl->non_zero_count_cache, 0, sizeof(sl->non_zero_count_cache));
      av_assert1(ref >= 0);
      /* FIXME: It is possible albeit uncommon that slice references
       * differ between slices. We take the easy approach and ignore
       * it for now. If this turns out to have any relevance in
       * practice then correct remapping should be added. */
      if (ref >= sl->ref_count[0])
          ref = 0;
      if (!sl->ref_list[0][ref].data[0]) {
          av_log(h->avctx, AV_LOG_DEBUG, "Reference not available for error concealing\n");
          ref = 0;
      }
      if ((sl->ref_list[0][ref].reference&3) != 3) {
          av_log(h->avctx, AV_LOG_DEBUG, "Reference invalid\n");
          return;
      }
      fill_rectangle(&h->cur_pic.ref_index[0][4 * sl->mb_xy],
                     2, 2, 2, ref, 1);
      fill_rectangle(&sl->ref_cache[0][scan8[0]], 4, 4, 8, ref, 1);
      fill_rectangle(sl->mv_cache[0][scan8[0]], 4, 4, 8,
                     pack16to32((*mv)[0][0][0], (*mv)[0][0][1]), 4);
      sl->mb_mbaff =
      sl->mb_field_decoding_flag = 0;
      ff_h264_hl_decode_mb(h, &h->slice_ctx[0]);
  }
  
  void ff_h264_draw_horiz_band(const H264Context *h, H264SliceContext *sl,
                               int y, int height)
  {
      AVCodecContext *avctx = h->avctx;
      const AVFrame   *src  = h->cur_pic.f;
      const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(avctx->pix_fmt);
      int vshift = desc->log2_chroma_h;
      const int field_pic = h->picture_structure != PICT_FRAME;
      if (field_pic) {
          height <<= 1;
          y      <<= 1;
      }
  
      height = FFMIN(height, avctx->height - y);
  
      if (field_pic && h->first_field && !(avctx->slice_flags & SLICE_FLAG_ALLOW_FIELD))
          return;
  
      if (avctx->draw_horiz_band) {
          int offset[AV_NUM_DATA_POINTERS];
          int i;
  
          offset[0] = y * src->linesize[0];
          offset[1] =
          offset[2] = (y >> vshift) * src->linesize[1];
          for (i = 3; i < AV_NUM_DATA_POINTERS; i++)
              offset[i] = 0;
  
          emms_c();
  
          avctx->draw_horiz_band(avctx, src, offset,
                                 y, h->picture_structure, height);
      }
  }
  
  /**
   * Check if the top & left blocks are available if needed and
   * change the dc mode so it only uses the available blocks.
   */
  int ff_h264_check_intra4x4_pred_mode(const H264Context *h, H264SliceContext *sl)
  {
      static const int8_t top[12] = {
          -1, 0, LEFT_DC_PRED, -1, -1, -1, -1, -1, 0
      };
      static const int8_t left[12] = {
          0, -1, TOP_DC_PRED, 0, -1, -1, -1, 0, -1, DC_128_PRED
      };
      int i;
  
      if (!(sl->top_samples_available & 0x8000)) {
          for (i = 0; i < 4; i++) {
              int status = top[sl->intra4x4_pred_mode_cache[scan8[0] + i]];
              if (status < 0) {
                  av_log(h->avctx, AV_LOG_ERROR,
                         "top block unavailable for requested intra4x4 mode %d at %d %d\n",
                         status, sl->mb_x, sl->mb_y);
                  return AVERROR_INVALIDDATA;
              } else if (status) {
                  sl->intra4x4_pred_mode_cache[scan8[0] + i] = status;
              }
          }
      }
  
      if ((sl->left_samples_available & 0x8888) != 0x8888) {
          static const int mask[4] = { 0x8000, 0x2000, 0x80, 0x20 };
          for (i = 0; i < 4; i++)
              if (!(sl->left_samples_available & mask[i])) {
                  int status = left[sl->intra4x4_pred_mode_cache[scan8[0] + 8 * i]];
                  if (status < 0) {
                      av_log(h->avctx, AV_LOG_ERROR,
                             "left block unavailable for requested intra4x4 mode %d at %d %d\n",
                             status, sl->mb_x, sl->mb_y);
                      return AVERROR_INVALIDDATA;
                  } else if (status) {
                      sl->intra4x4_pred_mode_cache[scan8[0] + 8 * i] = status;
                  }
              }
      }
  
      return 0;
  } // FIXME cleanup like ff_h264_check_intra_pred_mode
  
  /**
   * Check if the top & left blocks are available if needed and
   * change the dc mode so it only uses the available blocks.
   */
  int ff_h264_check_intra_pred_mode(const H264Context *h, H264SliceContext *sl,
                                    int mode, int is_chroma)
  {
      static const int8_t top[4]  = { LEFT_DC_PRED8x8, 1, -1, -1 };
      static const int8_t left[5] = { TOP_DC_PRED8x8, -1,  2, -1, DC_128_PRED8x8 };
  
      if (mode > 3U) {
          av_log(h->avctx, AV_LOG_ERROR,
                 "out of range intra chroma pred mode at %d %d\n",
                 sl->mb_x, sl->mb_y);
          return AVERROR_INVALIDDATA;
      }
  
      if (!(sl->top_samples_available & 0x8000)) {
          mode = top[mode];
          if (mode < 0) {
              av_log(h->avctx, AV_LOG_ERROR,
                     "top block unavailable for requested intra mode at %d %d\n",
                     sl->mb_x, sl->mb_y);
              return AVERROR_INVALIDDATA;
          }
      }
  
      if ((sl->left_samples_available & 0x8080) != 0x8080) {
          mode = left[mode];
          if (mode < 0) {
              av_log(h->avctx, AV_LOG_ERROR,
                     "left block unavailable for requested intra mode at %d %d\n",
                     sl->mb_x, sl->mb_y);
              return AVERROR_INVALIDDATA;
          }
          if (is_chroma && (sl->left_samples_available & 0x8080)) {
              // mad cow disease mode, aka MBAFF + constrained_intra_pred
              mode = ALZHEIMER_DC_L0T_PRED8x8 +
                     (!(sl->left_samples_available & 0x8000)) +
                     2 * (mode == DC_128_PRED8x8);
          }
      }
  
      return mode;
  }
  
  const uint8_t *ff_h264_decode_nal(H264Context *h, H264SliceContext *sl,
                                    const uint8_t *src,
                                    int *dst_length, int *consumed, int length)
  {
      int i, si, di;
      uint8_t *dst;
  
      // src[0]&0x80; // forbidden bit
      h->nal_ref_idc   = src[0] >> 5;
      h->nal_unit_type = src[0] & 0x1F;
  
      src++;
      length--;
  
  #define STARTCODE_TEST                                                  \
      if (i + 2 < length && src[i + 1] == 0 && src[i + 2] <= 3) {         \
          if (src[i + 2] != 3 && src[i + 2] != 0) {                       \
              /* startcode, so we must be past the end */                 \
              length = i;                                                 \
          }                                                               \
          break;                                                          \
      }
  
  #if HAVE_FAST_UNALIGNED
  #define FIND_FIRST_ZERO                                                 \
      if (i > 0 && !src[i])                                               \
          i--;                                                            \
      while (src[i])                                                      \
          i++
  
  #if HAVE_FAST_64BIT
      for (i = 0; i + 1 < length; i += 9) {
          if (!((~AV_RN64A(src + i) &
                 (AV_RN64A(src + i) - 0x0100010001000101ULL)) &
                0x8000800080008080ULL))
              continue;
          FIND_FIRST_ZERO;
          STARTCODE_TEST;
          i -= 7;
      }
  #else
      for (i = 0; i + 1 < length; i += 5) {
          if (!((~AV_RN32A(src + i) &
                 (AV_RN32A(src + i) - 0x01000101U)) &
                0x80008080U))
              continue;
          FIND_FIRST_ZERO;
          STARTCODE_TEST;
          i -= 3;
      }
  #endif
  #else
      for (i = 0; i + 1 < length; i += 2) {
          if (src[i])
              continue;
          if (i > 0 && src[i - 1] == 0)
              i--;
          STARTCODE_TEST;
      }
  #endif
  
      av_fast_padded_malloc(&sl->rbsp_buffer, &sl->rbsp_buffer_size, length+MAX_MBPAIR_SIZE);
      dst = sl->rbsp_buffer;
  
      if (!dst)
          return NULL;
  
      if(i>=length-1){ //no escaped 0
          *dst_length= length;
          *consumed= length+1; //+1 for the header
          if(h->avctx->flags2 & AV_CODEC_FLAG2_FAST){
              return src;
          }else{
              memcpy(dst, src, length);
              return dst;
          }
      }
  
      memcpy(dst, src, i);
      si = di = i;
      while (si + 2 < length) {
          // remove escapes (very rare 1:2^22)
          if (src[si + 2] > 3) {
              dst[di++] = src[si++];
              dst[di++] = src[si++];
          } else if (src[si] == 0 && src[si + 1] == 0 && src[si + 2] != 0) {
              if (src[si + 2] == 3) { // escape
                  dst[di++]  = 0;
                  dst[di++]  = 0;
                  si        += 3;
                  continue;
              } else // next start code
                  goto nsc;
          }
  
          dst[di++] = src[si++];
      }
      while (si < length)
          dst[di++] = src[si++];
  
  nsc:
      memset(dst + di, 0, AV_INPUT_BUFFER_PADDING_SIZE);
  
      *dst_length = di;
      *consumed   = si + 1; // +1 for the header
      /* FIXME store exact number of bits in the getbitcontext
       * (it is needed for decoding) */
      return dst;
  }
  
  /**
   * Identify the exact end of the bitstream
   * @return the length of the trailing, or 0 if damaged
   */
  static int decode_rbsp_trailing(H264Context *h, const uint8_t *src)
  {
      int v = *src;
      int r;
  
      ff_tlog(h->avctx, "rbsp trailing %X\n", v);
  
      for (r = 1; r < 9; r++) {
          if (v & 1)
              return r;
          v >>= 1;
      }
      return 0;
  }
  
  void ff_h264_free_tables(H264Context *h)
  {
      int i;
  
      av_freep(&h->intra4x4_pred_mode);
      av_freep(&h->chroma_pred_mode_table);
      av_freep(&h->cbp_table);
      av_freep(&h->mvd_table[0]);
      av_freep(&h->mvd_table[1]);
      av_freep(&h->direct_table);
      av_freep(&h->non_zero_count);
      av_freep(&h->slice_table_base);
      h->slice_table = NULL;
      av_freep(&h->list_counts);
  
      av_freep(&h->mb2b_xy);
      av_freep(&h->mb2br_xy);
  
      av_buffer_pool_uninit(&h->qscale_table_pool);
      av_buffer_pool_uninit(&h->mb_type_pool);
      av_buffer_pool_uninit(&h->motion_val_pool);
      av_buffer_pool_uninit(&h->ref_index_pool);
  
      for (i = 0; i < h->nb_slice_ctx; i++) {
          H264SliceContext *sl = &h->slice_ctx[i];
  
          av_freep(&sl->dc_val_base);
          av_freep(&sl->er.mb_index2xy);
          av_freep(&sl->er.error_status_table);
          av_freep(&sl->er.er_temp_buffer);
  
          av_freep(&sl->bipred_scratchpad);
          av_freep(&sl->edge_emu_buffer);
          av_freep(&sl->top_borders[0]);
          av_freep(&sl->top_borders[1]);
  
          sl->bipred_scratchpad_allocated = 0;
          sl->edge_emu_buffer_allocated   = 0;
          sl->top_borders_allocated[0]    = 0;
          sl->top_borders_allocated[1]    = 0;
      }
  }
  
  int ff_h264_alloc_tables(H264Context *h)
  {
      const int big_mb_num = h->mb_stride * (h->mb_height + 1);
      const int row_mb_num = 2*h->mb_stride*FFMAX(h->avctx->thread_count, 1);
      int x, y;
  
      FF_ALLOCZ_ARRAY_OR_GOTO(h->avctx, h->intra4x4_pred_mode,
                        row_mb_num, 8 * sizeof(uint8_t), fail)
      h->slice_ctx[0].intra4x4_pred_mode = h->intra4x4_pred_mode;
  
      FF_ALLOCZ_OR_GOTO(h->avctx, h->non_zero_count,
                        big_mb_num * 48 * sizeof(uint8_t), fail)
      FF_ALLOCZ_OR_GOTO(h->avctx, h->slice_table_base,
                        (big_mb_num + h->mb_stride) * sizeof(*h->slice_table_base), fail)
      FF_ALLOCZ_OR_GOTO(h->avctx, h->cbp_table,
                        big_mb_num * sizeof(uint16_t), fail)
      FF_ALLOCZ_OR_GOTO(h->avctx, h->chroma_pred_mode_table,
                        big_mb_num * sizeof(uint8_t), fail)
      FF_ALLOCZ_ARRAY_OR_GOTO(h->avctx, h->mvd_table[0],
                        row_mb_num, 16 * sizeof(uint8_t), fail);
      FF_ALLOCZ_ARRAY_OR_GOTO(h->avctx, h->mvd_table[1],
                        row_mb_num, 16 * sizeof(uint8_t), fail);
      h->slice_ctx[0].mvd_table[0] = h->mvd_table[0];
      h->slice_ctx[0].mvd_table[1] = h->mvd_table[1];
  
      FF_ALLOCZ_OR_GOTO(h->avctx, h->direct_table,
                        4 * big_mb_num * sizeof(uint8_t), fail);
      FF_ALLOCZ_OR_GOTO(h->avctx, h->list_counts,
                        big_mb_num * sizeof(uint8_t), fail)
  
      memset(h->slice_table_base, -1,
             (big_mb_num + h->mb_stride) * sizeof(*h->slice_table_base));
      h->slice_table = h->slice_table_base + h->mb_stride * 2 + 1;
  
      FF_ALLOCZ_OR_GOTO(h->avctx, h->mb2b_xy,
                        big_mb_num * sizeof(uint32_t), fail);
      FF_ALLOCZ_OR_GOTO(h->avctx, h->mb2br_xy,
                        big_mb_num * sizeof(uint32_t), fail);
      for (y = 0; y < h->mb_height; y++)
          for (x = 0; x < h->mb_width; x++) {
              const int mb_xy = x + y * h->mb_stride;
              const int b_xy  = 4 * x + 4 * y * h->b_stride;
  
              h->mb2b_xy[mb_xy]  = b_xy;
              h->mb2br_xy[mb_xy] = 8 * (FMO ? mb_xy : (mb_xy % (2 * h->mb_stride)));
          }
  
      if (!h->dequant4_coeff[0])
          ff_h264_init_dequant_tables(h);
  
      return 0;
  
  fail:
      ff_h264_free_tables(h);
      return AVERROR(ENOMEM);
  }
  
  /**
   * Init context
   * Allocate buffers which are not shared amongst multiple threads.
   */
  int ff_h264_slice_context_init(H264Context *h, H264SliceContext *sl)
  {
      ERContext *er = &sl->er;
      int mb_array_size = h->mb_height * h->mb_stride;
      int y_size  = (2 * h->mb_width + 1) * (2 * h->mb_height + 1);
      int c_size  = h->mb_stride * (h->mb_height + 1);
      int yc_size = y_size + 2   * c_size;
      int x, y, i;
  
      sl->ref_cache[0][scan8[5]  + 1] =
      sl->ref_cache[0][scan8[7]  + 1] =
      sl->ref_cache[0][scan8[13] + 1] =
      sl->ref_cache[1][scan8[5]  + 1] =
      sl->ref_cache[1][scan8[7]  + 1] =
      sl->ref_cache[1][scan8[13] + 1] = PART_NOT_AVAILABLE;
  
      if (sl != h->slice_ctx) {
          memset(er, 0, sizeof(*er));
      } else
      if (CONFIG_ERROR_RESILIENCE) {
  
          /* init ER */
          er->avctx          = h->avctx;
          er->decode_mb      = h264_er_decode_mb;
          er->opaque         = h;
          er->quarter_sample = 1;
  
          er->mb_num      = h->mb_num;
          er->mb_width    = h->mb_width;
          er->mb_height   = h->mb_height;
          er->mb_stride   = h->mb_stride;
          er->b8_stride   = h->mb_width * 2 + 1;
  
          // error resilience code looks cleaner with this
          FF_ALLOCZ_OR_GOTO(h->avctx, er->mb_index2xy,
                            (h->mb_num + 1) * sizeof(int), fail);
  
          for (y = 0; y < h->mb_height; y++)
              for (x = 0; x < h->mb_width; x++)
                  er->mb_index2xy[x + y * h->mb_width] = x + y * h->mb_stride;
  
          er->mb_index2xy[h->mb_height * h->mb_width] = (h->mb_height - 1) *
                                                        h->mb_stride + h->mb_width;
  
          FF_ALLOCZ_OR_GOTO(h->avctx, er->error_status_table,
                            mb_array_size * sizeof(uint8_t), fail);
  
          FF_ALLOC_OR_GOTO(h->avctx, er->er_temp_buffer,
                           h->mb_height * h->mb_stride, fail);
  
          FF_ALLOCZ_OR_GOTO(h->avctx, sl->dc_val_base,
                            yc_size * sizeof(int16_t), fail);
          er->dc_val[0] = sl->dc_val_base + h->mb_width * 2 + 2;
          er->dc_val[1] = sl->dc_val_base + y_size + h->mb_stride + 1;
          er->dc_val[2] = er->dc_val[1] + c_size;
          for (i = 0; i < yc_size; i++)
              sl->dc_val_base[i] = 1024;
      }
  
      return 0;
  
  fail:
      return AVERROR(ENOMEM); // ff_h264_free_tables will clean up for us
  }
  
  static int decode_nal_units(H264Context *h, const uint8_t *buf, int buf_size,
                              int parse_extradata);
  
  int ff_h264_decode_extradata(H264Context *h, const uint8_t *buf, int size)
  {
      AVCodecContext *avctx = h->avctx;
      int ret;
  
      if (!buf || size <= 0)
          return -1;
  
      if (buf[0] == 1) {
          int i, cnt, nalsize;
          const unsigned char *p = buf;
  
          h->is_avc = 1;
  
          if (size < 7) {
              av_log(avctx, AV_LOG_ERROR,
                     "avcC %d too short\n", size);
              return AVERROR_INVALIDDATA;
          }
          /* sps and pps in the avcC always have length coded with 2 bytes,
           * so put a fake nal_length_size = 2 while parsing them */
          h->nal_length_size = 2;
          // Decode sps from avcC
          cnt = *(p + 5) & 0x1f; // Number of sps
          p  += 6;
          for (i = 0; i < cnt; i++) {
              nalsize = AV_RB16(p) + 2;
              if(nalsize > size - (p-buf))
                  return AVERROR_INVALIDDATA;
              ret = decode_nal_units(h, p, nalsize, 1);
              if (ret < 0) {
                  av_log(avctx, AV_LOG_ERROR,
                         "Decoding sps %d from avcC failed\n", i);
                  return ret;
              }
              p += nalsize;
          }
          // Decode pps from avcC
          cnt = *(p++); // Number of pps
          for (i = 0; i < cnt; i++) {
              nalsize = AV_RB16(p) + 2;
              if(nalsize > size - (p-buf))
                  return AVERROR_INVALIDDATA;
              ret = decode_nal_units(h, p, nalsize, 1);
              if (ret < 0) {
                  av_log(avctx, AV_LOG_ERROR,
                         "Decoding pps %d from avcC failed\n", i);
                  return ret;
              }
              p += nalsize;
          }
          // Store right nal length size that will be used to parse all other nals
          h->nal_length_size = (buf[4] & 0x03) + 1;
      } else {
          h->is_avc = 0;
          ret = decode_nal_units(h, buf, size, 1);
          if (ret < 0)
              return ret;
      }
      return size;
  }
  
  static int h264_init_context(AVCodecContext *avctx, H264Context *h)
  {
      int i;
  
      h->avctx                 = avctx;
      h->backup_width          = -1;
      h->backup_height         = -1;
      h->backup_pix_fmt        = AV_PIX_FMT_NONE;
      h->dequant_coeff_pps     = -1;
      h->current_sps_id        = -1;
      h->cur_chroma_format_idc = -1;
  
      h->picture_structure     = PICT_FRAME;
      h->slice_context_count   = 1;
      h->workaround_bugs       = avctx->workaround_bugs;
      h->flags                 = avctx->flags;
      h->prev_poc_msb          = 1 << 16;
      h->x264_build            = -1;
      h->recovery_frame        = -1;
      h->frame_recovered       = 0;
      h->prev_frame_num        = -1;
      h->sei_fpa.frame_packing_arrangement_cancel_flag = -1;
  
      h->next_outputed_poc = INT_MIN;
      for (i = 0; i < MAX_DELAYED_PIC_COUNT; i++)
          h->last_pocs[i] = INT_MIN;
  
      ff_h264_reset_sei(h);
  
      avctx->chroma_sample_location = AVCHROMA_LOC_LEFT;
  
      h->nb_slice_ctx = (avctx->active_thread_type & FF_THREAD_SLICE) ?  H264_MAX_THREADS : 1;
      h->slice_ctx = av_mallocz_array(h->nb_slice_ctx, sizeof(*h->slice_ctx));
      if (!h->slice_ctx) {
          h->nb_slice_ctx = 0;
          return AVERROR(ENOMEM);
      }
  
      for (i = 0; i < H264_MAX_PICTURE_COUNT; i++) {
          h->DPB[i].f = av_frame_alloc();
          if (!h->DPB[i].f)
              return AVERROR(ENOMEM);
      }
  
      h->cur_pic.f = av_frame_alloc();
      if (!h->cur_pic.f)
          return AVERROR(ENOMEM);
  
      h->last_pic_for_ec.f = av_frame_alloc();
      if (!h->last_pic_for_ec.f)
          return AVERROR(ENOMEM);
  
      for (i = 0; i < h->nb_slice_ctx; i++)
          h->slice_ctx[i].h264 = h;
  
      return 0;
  }
  
  av_cold int ff_h264_decode_init(AVCodecContext *avctx)
  {
      H264Context *h = avctx->priv_data;
      int ret;
  
      ret = h264_init_context(avctx, h);
      if (ret < 0)
          return ret;
  
      /* set defaults */
      if (!avctx->has_b_frames)
          h->low_delay = 1;
  
      ff_h264_decode_init_vlc();
  
      ff_init_cabac_states();
  
      if (avctx->codec_id == AV_CODEC_ID_H264) {
          if (avctx->ticks_per_frame == 1) {
              if(h->avctx->time_base.den < INT_MAX/2) {
                  h->avctx->time_base.den *= 2;
              } else
                  h->avctx->time_base.num /= 2;
          }
          avctx->ticks_per_frame = 2;
      }
  
      if (avctx->extradata_size > 0 && avctx->extradata) {
          ret = ff_h264_decode_extradata(h, avctx->extradata, avctx->extradata_size);
          if (ret < 0) {
              ff_h264_free_context(h);
              return ret;
          }
      }
  
      if (h->sps.bitstream_restriction_flag &&
          h->avctx->has_b_frames < h->sps.num_reorder_frames) {
          h->avctx->has_b_frames = h->sps.num_reorder_frames;
          h->low_delay           = 0;
      }
  
      avctx->internal->allocate_progress = 1;
  
      ff_h264_flush_change(h);
  
      if (h->enable_er < 0 && (avctx->active_thread_type & FF_THREAD_SLICE))
          h->enable_er = 0;
  
      if (h->enable_er && (avctx->active_thread_type & FF_THREAD_SLICE)) {
          av_log(avctx, AV_LOG_WARNING,
                 "Error resilience with slice threads is enabled. It is unsafe and unsupported and may crash. "
                 "Use it at your own risk\n");
      }
  
      return 0;
  }
  
  static int decode_init_thread_copy(AVCodecContext *avctx)
  {
      H264Context *h = avctx->priv_data;
      int ret;
  
      if (!avctx->internal->is_copy)
          return 0;
  
      memset(h, 0, sizeof(*h));
  
      ret = h264_init_context(avctx, h);
      if (ret < 0)
          return ret;
  
      h->context_initialized = 0;
  
      return 0;
  }
  
  /**
   * Run setup operations that must be run after slice header decoding.
   * This includes finding the next displayed frame.
   *
   * @param h h264 master context
   * @param setup_finished enough NALs have been read that we can call
   * ff_thread_finish_setup()
   */
  static void decode_postinit(H264Context *h, int setup_finished)
  {
      H264Picture *out = h->cur_pic_ptr;
      H264Picture *cur = h->cur_pic_ptr;
      int i, pics, out_of_order, out_idx;
  
      h->cur_pic_ptr->f->pict_type = h->pict_type;
  
      if (h->next_output_pic)
          return;
  
      if (cur->field_poc[0] == INT_MAX || cur->field_poc[1] == INT_MAX) {
          /* FIXME: if we have two PAFF fields in one packet, we can't start
           * the next thread here. If we have one field per packet, we can.
           * The check in decode_nal_units() is not good enough to find this
           * yet, so we assume the worst for now. */
          // if (setup_finished)
          //    ff_thread_finish_setup(h->avctx);
          if (cur->field_poc[0] == INT_MAX && cur->field_poc[1] == INT_MAX)
              return;
          if (h->avctx->hwaccel || h->missing_fields <=1)
              return;
      }
  
      cur->f->interlaced_frame = 0;
      cur->f->repeat_pict      = 0;
  
      /* Signal interlacing information externally. */
      /* Prioritize picture timing SEI information over used
       * decoding process if it exists. */
  
      if (h->sps.pic_struct_present_flag) {
          switch (h->sei_pic_struct) {
          case SEI_PIC_STRUCT_FRAME:
              break;
          case SEI_PIC_STRUCT_TOP_FIELD:
          case SEI_PIC_STRUCT_BOTTOM_FIELD:
              cur->f->interlaced_frame = 1;
              break;
          case SEI_PIC_STRUCT_TOP_BOTTOM:
          case SEI_PIC_STRUCT_BOTTOM_TOP:
              if (FIELD_OR_MBAFF_PICTURE(h))
                  cur->f->interlaced_frame = 1;
              else
                  // try to flag soft telecine progressive
                  cur->f->interlaced_frame = h->prev_interlaced_frame;
              break;
          case SEI_PIC_STRUCT_TOP_BOTTOM_TOP:
          case SEI_PIC_STRUCT_BOTTOM_TOP_BOTTOM:
              /* Signal the possibility of telecined film externally
               * (pic_struct 5,6). From these hints, let the applications
               * decide if they apply deinterlacing. */
              cur->f->repeat_pict = 1;
              break;
          case SEI_PIC_STRUCT_FRAME_DOUBLING:
              cur->f->repeat_pict = 2;
              break;
          case SEI_PIC_STRUCT_FRAME_TRIPLING:
              cur->f->repeat_pict = 4;
              break;
          }
  
          if ((h->sei_ct_type & 3) &&
              h->sei_pic_struct <= SEI_PIC_STRUCT_BOTTOM_TOP)
              cur->f->interlaced_frame = (h->sei_ct_type & (1 << 1)) != 0;
      } else {
          /* Derive interlacing flag from used decoding process. */
          cur->f->interlaced_frame = FIELD_OR_MBAFF_PICTURE(h);
      }
      h->prev_interlaced_frame = cur->f->interlaced_frame;
  
      if (cur->field_poc[0] != cur->field_poc[1]) {
          /* Derive top_field_first from field pocs. */
          cur->f->top_field_first = cur->field_poc[0] < cur->field_poc[1];
      } else {
          if (cur->f->interlaced_frame || h->sps.pic_struct_present_flag) {
              /* Use picture timing SEI information. Even if it is a
               * information of a past frame, better than nothing. */
              if (h->sei_pic_struct == SEI_PIC_STRUCT_TOP_BOTTOM ||
                  h->sei_pic_struct == SEI_PIC_STRUCT_TOP_BOTTOM_TOP)
                  cur->f->top_field_first = 1;
              else
                  cur->f->top_field_first = 0;
          } else {
              /* Most likely progressive */
              cur->f->top_field_first = 0;
          }
      }
  
      if (h->sei_frame_packing_present &&
          h->frame_packing_arrangement_type >= 0 &&
          h->frame_packing_arrangement_type <= 6 &&
          h->content_interpretation_type > 0 &&
          h->content_interpretation_type < 3) {
          AVStereo3D *stereo = av_stereo3d_create_side_data(cur->f);
          if (stereo) {
          switch (h->frame_packing_arrangement_type) {
          case 0:
              stereo->type = AV_STEREO3D_CHECKERBOARD;
              break;
          case 1:
              stereo->type = AV_STEREO3D_COLUMNS;
              break;
          case 2:
              stereo->type = AV_STEREO3D_LINES;
              break;
          case 3:
              if (h->quincunx_subsampling)
                  stereo->type = AV_STEREO3D_SIDEBYSIDE_QUINCUNX;
              else
                  stereo->type = AV_STEREO3D_SIDEBYSIDE;
              break;
          case 4:
              stereo->type = AV_STEREO3D_TOPBOTTOM;
              break;
          case 5:
              stereo->type = AV_STEREO3D_FRAMESEQUENCE;
              break;
          case 6:
              stereo->type = AV_STEREO3D_2D;
              break;
          }
  
          if (h->content_interpretation_type == 2)
              stereo->flags = AV_STEREO3D_FLAG_INVERT;
          }
      }
  
      if (h->sei_display_orientation_present &&
          (h->sei_anticlockwise_rotation || h->sei_hflip || h->sei_vflip)) {
          double angle = h->sei_anticlockwise_rotation * 360 / (double) (1 << 16);
          AVFrameSideData *rotation = av_frame_new_side_data(cur->f,
                                                             AV_FRAME_DATA_DISPLAYMATRIX,
                                                             sizeof(int32_t) * 9);
          if (rotation) {
              av_display_rotation_set((int32_t *)rotation->data, angle);
              av_display_matrix_flip((int32_t *)rotation->data,
                                     h->sei_hflip, h->sei_vflip);
          }
      }
  
      if (h->sei_reguserdata_afd_present) {
          AVFrameSideData *sd = av_frame_new_side_data(cur->f, AV_FRAME_DATA_AFD,
                                                       sizeof(uint8_t));
  
          if (sd) {
              *sd->data = h->active_format_description;
              h->sei_reguserdata_afd_present = 0;
          }
      }
  
      if (h->a53_caption) {
          AVFrameSideData *sd = av_frame_new_side_data(cur->f,
                                                       AV_FRAME_DATA_A53_CC,
                                                       h->a53_caption_size);
          if (sd)
              memcpy(sd->data, h->a53_caption, h->a53_caption_size);
          av_freep(&h->a53_caption);
          h->a53_caption_size = 0;
          h->avctx->properties |= FF_CODEC_PROPERTY_CLOSED_CAPTIONS;
      }
  
      cur->mmco_reset = h->mmco_reset;
      h->mmco_reset = 0;
  
      // FIXME do something with unavailable reference frames
  
      /* Sort B-frames into display order */
  
      if (h->sps.bitstream_restriction_flag &&
          h->avctx->has_b_frames < h->sps.num_reorder_frames) {
          h->avctx->has_b_frames = h->sps.num_reorder_frames;
          h->low_delay           = 0;
      }
  
      if (h->avctx->strict_std_compliance >= FF_COMPLIANCE_STRICT &&
          !h->sps.bitstream_restriction_flag) {
          h->avctx->has_b_frames = MAX_DELAYED_PIC_COUNT - 1;
          h->low_delay           = 0;
      }
  
      for (i = 0; 1; i++) {
          if(i == MAX_DELAYED_PIC_COUNT || cur->poc < h->last_pocs[i]){
              if(i)
                  h->last_pocs[i-1] = cur->poc;
              break;
          } else if(i) {
              h->last_pocs[i-1]= h->last_pocs[i];
          }
      }
      out_of_order = MAX_DELAYED_PIC_COUNT - i;
      if(   cur->f->pict_type == AV_PICTURE_TYPE_B
         || (h->last_pocs[MAX_DELAYED_PIC_COUNT-2] > INT_MIN && h->last_pocs[MAX_DELAYED_PIC_COUNT-1] - h->last_pocs[MAX_DELAYED_PIC_COUNT-2] > 2))
          out_of_order = FFMAX(out_of_order, 1);
      if (out_of_order == MAX_DELAYED_PIC_COUNT) {
          av_log(h->avctx, AV_LOG_VERBOSE, "Invalid POC %d<%d\n", cur->poc, h->last_pocs[0]);
          for (i = 1; i < MAX_DELAYED_PIC_COUNT; i++)
              h->last_pocs[i] = INT_MIN;
          h->last_pocs[0] = cur->poc;
          cur->mmco_reset = 1;
      } else if(h->avctx->has_b_frames < out_of_order && !h->sps.bitstream_restriction_flag){
          av_log(h->avctx, AV_LOG_VERBOSE, "Increasing reorder buffer to %d\n", out_of_order);
          h->avctx->has_b_frames = out_of_order;
          h->low_delay = 0;
      }
  
      pics = 0;
      while (h->delayed_pic[pics])
          pics++;
  
      av_assert0(pics <= MAX_DELAYED_PIC_COUNT);
  
      h->delayed_pic[pics++] = cur;
      if (cur->reference == 0)
          cur->reference = DELAYED_PIC_REF;
  
      out     = h->delayed_pic[0];
      out_idx = 0;
      for (i = 1; h->delayed_pic[i] &&
                  !h->delayed_pic[i]->f->key_frame &&
                  !h->delayed_pic[i]->mmco_reset;
           i++)
          if (h->delayed_pic[i]->poc < out->poc) {
              out     = h->delayed_pic[i];
              out_idx = i;
          }
      if (h->avctx->has_b_frames == 0 &&
          (h->delayed_pic[0]->f->key_frame || h->delayed_pic[0]->mmco_reset))
          h->next_outputed_poc = INT_MIN;
      out_of_order = out->poc < h->next_outputed_poc;
  
      if (out_of_order || pics > h->avctx->has_b_frames) {
          out->reference &= ~DELAYED_PIC_REF;
          // for frame threading, the owner must be the second field's thread or
          // else the first thread can release the picture and reuse it unsafely
          for (i = out_idx; h->delayed_pic[i]; i++)
              h->delayed_pic[i] = h->delayed_pic[i + 1];
      }
      if (!out_of_order && pics > h->avctx->has_b_frames) {
          h->next_output_pic = out;
          if (out_idx == 0 && h->delayed_pic[0] && (h->delayed_pic[0]->f->key_frame || h->delayed_pic[0]->mmco_reset)) {
              h->next_outputed_poc = INT_MIN;
          } else
              h->next_outputed_poc = out->poc;
      } else {
          av_log(h->avctx, AV_LOG_DEBUG, "no picture %s\n", out_of_order ? "ooo" : "");
      }
  
      if (h->next_output_pic) {
          if (h->next_output_pic->recovered) {
              // We have reached an recovery point and all frames after it in
              // display order are "recovered".
              h->frame_recovered |= FRAME_RECOVERED_SEI;
          }
          h->next_output_pic->recovered |= !!(h->frame_recovered & FRAME_RECOVERED_SEI);
      }
  
      if (setup_finished && !h->avctx->hwaccel) {
          ff_thread_finish_setup(h->avctx);
  
          if (h->avctx->active_thread_type & FF_THREAD_FRAME)
              h->setup_finished = 1;
      }
  }
  
  int ff_pred_weight_table(H264Context *h, H264SliceContext *sl)
  {
      int list, i;
      int luma_def, chroma_def;
  
      sl->use_weight             = 0;
      sl->use_weight_chroma      = 0;
      sl->luma_log2_weight_denom = get_ue_golomb(&sl->gb);
      if (h->sps.chroma_format_idc)
          sl->chroma_log2_weight_denom = get_ue_golomb(&sl->gb);
  
      if (sl->luma_log2_weight_denom > 7U) {
          av_log(h->avctx, AV_LOG_ERROR, "luma_log2_weight_denom %d is out of range\n", sl->luma_log2_weight_denom);
          sl->luma_log2_weight_denom = 0;
      }
      if (sl->chroma_log2_weight_denom > 7U) {
          av_log(h->avctx, AV_LOG_ERROR, "chroma_log2_weight_denom %d is out of range\n", sl->chroma_log2_weight_denom);
          sl->chroma_log2_weight_denom = 0;
      }
  
      luma_def   = 1 << sl->luma_log2_weight_denom;
      chroma_def = 1 << sl->chroma_log2_weight_denom;
  
      for (list = 0; list < 2; list++) {
          sl->luma_weight_flag[list]   = 0;
          sl->chroma_weight_flag[list] = 0;
          for (i = 0; i < sl->ref_count[list]; i++) {
              int luma_weight_flag, chroma_weight_flag;
  
              luma_weight_flag = get_bits1(&sl->gb);
              if (luma_weight_flag) {
                  sl->luma_weight[i][list][0] = get_se_golomb(&sl->gb);
                  sl->luma_weight[i][list][1] = get_se_golomb(&sl->gb);
                  if (sl->luma_weight[i][list][0] != luma_def ||
                      sl->luma_weight[i][list][1] != 0) {
                      sl->use_weight             = 1;
                      sl->luma_weight_flag[list] = 1;
                  }
              } else {
                  sl->luma_weight[i][list][0] = luma_def;
                  sl->luma_weight[i][list][1] = 0;
              }
  
              if (h->sps.chroma_format_idc) {
                  chroma_weight_flag = get_bits1(&sl->gb);
                  if (chroma_weight_flag) {
                      int j;
                      for (j = 0; j < 2; j++) {
                          sl->chroma_weight[i][list][j][0] = get_se_golomb(&sl->gb);
                          sl->chroma_weight[i][list][j][1] = get_se_golomb(&sl->gb);
                          if (sl->chroma_weight[i][list][j][0] != chroma_def ||
                              sl->chroma_weight[i][list][j][1] != 0) {
                              sl->use_weight_chroma        = 1;
                              sl->chroma_weight_flag[list] = 1;
                          }
                      }
                  } else {
                      int j;
                      for (j = 0; j < 2; j++) {
                          sl->chroma_weight[i][list][j][0] = chroma_def;
                          sl->chroma_weight[i][list][j][1] = 0;
                      }
                  }
              }
          }
          if (sl->slice_type_nos != AV_PICTURE_TYPE_B)
              break;
      }
      sl->use_weight = sl->use_weight || sl->use_weight_chroma;
      return 0;
  }
  
  /**
   * instantaneous decoder refresh.
   */
  static void idr(H264Context *h)
  {
      int i;
      ff_h264_remove_all_refs(h);
      h->prev_frame_num        =
      h->prev_frame_num_offset = 0;
      h->prev_poc_msb          = 1<<16;
      h->prev_poc_lsb          = 0;
      for (i = 0; i < MAX_DELAYED_PIC_COUNT; i++)
          h->last_pocs[i] = INT_MIN;
  }
  
  /* forget old pics after a seek */
  void ff_h264_flush_change(H264Context *h)
  {
      int i, j;
  
      h->next_outputed_poc = INT_MIN;
      h->prev_interlaced_frame = 1;
      idr(h);
  
      h->prev_frame_num = -1;
      if (h->cur_pic_ptr) {
          h->cur_pic_ptr->reference = 0;
          for (j=i=0; h->delayed_pic[i]; i++)
              if (h->delayed_pic[i] != h->cur_pic_ptr)
                  h->delayed_pic[j++] = h->delayed_pic[i];
          h->delayed_pic[j] = NULL;
      }
      ff_h264_unref_picture(h, &h->last_pic_for_ec);
  
      h->first_field = 0;
      ff_h264_reset_sei(h);
      h->recovery_frame = -1;
      h->frame_recovered = 0;
      h->current_slice = 0;
      h->mmco_reset = 1;
      for (i = 0; i < h->nb_slice_ctx; i++)
          h->slice_ctx[i].list_count = 0;
  }
  
  /* forget old pics after a seek */
  static void flush_dpb(AVCodecContext *avctx)
  {
      H264Context *h = avctx->priv_data;
      int i;
  
      memset(h->delayed_pic, 0, sizeof(h->delayed_pic));
  
      ff_h264_flush_change(h);
  
      for (i = 0; i < H264_MAX_PICTURE_COUNT; i++)
          ff_h264_unref_picture(h, &h->DPB[i]);
      h->cur_pic_ptr = NULL;
      ff_h264_unref_picture(h, &h->cur_pic);
  
      h->mb_y = 0;
  
      ff_h264_free_tables(h);
      h->context_initialized = 0;
  }
  
  int ff_init_poc(H264Context *h, int pic_field_poc[2], int *pic_poc)
  {
      const int max_frame_num = 1 << h->sps.log2_max_frame_num;
      int field_poc[2];
  
      h->frame_num_offset = h->prev_frame_num_offset;
      if (h->frame_num < h->prev_frame_num)
          h->frame_num_offset += max_frame_num;
  
      if (h->sps.poc_type == 0) {
          const int max_poc_lsb = 1 << h->sps.log2_max_poc_lsb;
  
          if (h->poc_lsb < h->prev_poc_lsb &&
              h->prev_poc_lsb - h->poc_lsb >= max_poc_lsb / 2)
              h->poc_msb = h->prev_poc_msb + max_poc_lsb;
          else if (h->poc_lsb > h->prev_poc_lsb &&
                   h->prev_poc_lsb - h->poc_lsb < -max_poc_lsb / 2)
              h->poc_msb = h->prev_poc_msb - max_poc_lsb;
          else
              h->poc_msb = h->prev_poc_msb;
          field_poc[0] =
          field_poc[1] = h->poc_msb + h->poc_lsb;
          if (h->picture_structure == PICT_FRAME)
              field_poc[1] += h->delta_poc_bottom;
      } else if (h->sps.poc_type == 1) {
          int abs_frame_num, expected_delta_per_poc_cycle, expectedpoc;
          int i;
  
          if (h->sps.poc_cycle_length != 0)
              abs_frame_num = h->frame_num_offset + h->frame_num;
          else
              abs_frame_num = 0;
  
          if (h->nal_ref_idc == 0 && abs_frame_num > 0)
              abs_frame_num--;
  
          expected_delta_per_poc_cycle = 0;
          for (i = 0; i < h->sps.poc_cycle_length; i++)
              // FIXME integrate during sps parse
              expected_delta_per_poc_cycle += h->sps.offset_for_ref_frame[i];
  
          if (abs_frame_num > 0) {
              int poc_cycle_cnt          = (abs_frame_num - 1) / h->sps.poc_cycle_length;
              int frame_num_in_poc_cycle = (abs_frame_num - 1) % h->sps.poc_cycle_length;
  
              expectedpoc = poc_cycle_cnt * expected_delta_per_poc_cycle;
              for (i = 0; i <= frame_num_in_poc_cycle; i++)
                  expectedpoc = expectedpoc + h->sps.offset_for_ref_frame[i];
          } else
              expectedpoc = 0;
  
          if (h->nal_ref_idc == 0)
              expectedpoc = expectedpoc + h->sps.offset_for_non_ref_pic;
  
          field_poc[0] = expectedpoc + h->delta_poc[0];
          field_poc[1] = field_poc[0] + h->sps.offset_for_top_to_bottom_field;
  
          if (h->picture_structure == PICT_FRAME)
              field_poc[1] += h->delta_poc[1];
      } else {
          int poc = 2 * (h->frame_num_offset + h->frame_num);
  
          if (!h->nal_ref_idc)
              poc--;
  
          field_poc[0] = poc;
          field_poc[1] = poc;
      }
  
      if (h->picture_structure != PICT_BOTTOM_FIELD)
          pic_field_poc[0] = field_poc[0];
      if (h->picture_structure != PICT_TOP_FIELD)
          pic_field_poc[1] = field_poc[1];
      *pic_poc = FFMIN(pic_field_poc[0], pic_field_poc[1]);
  
      return 0;
  }
  
  /**
   * Compute profile from profile_idc and constraint_set?_flags.
   *
   * @param sps SPS
   *
   * @return profile as defined by FF_PROFILE_H264_*
   */
  int ff_h264_get_profile(SPS *sps)
  {
      int profile = sps->profile_idc;
  
      switch (sps->profile_idc) {
      case FF_PROFILE_H264_BASELINE:
          // constraint_set1_flag set to 1
          profile |= (sps->constraint_set_flags & 1 << 1) ? FF_PROFILE_H264_CONSTRAINED : 0;
          break;
      case FF_PROFILE_H264_HIGH_10:
      case FF_PROFILE_H264_HIGH_422:
      case FF_PROFILE_H264_HIGH_444_PREDICTIVE:
          // constraint_set3_flag set to 1
          profile |= (sps->constraint_set_flags & 1 << 3) ? FF_PROFILE_H264_INTRA : 0;
          break;
      }
  
      return profile;
  }
  
  int ff_set_ref_count(H264Context *h, H264SliceContext *sl)
  {
      int ref_count[2], list_count;
      int num_ref_idx_active_override_flag;
  
      // set defaults, might be overridden a few lines later
      ref_count[0] = h->pps.ref_count[0];
      ref_count[1] = h->pps.ref_count[1];
  
      if (sl->slice_type_nos != AV_PICTURE_TYPE_I) {
          unsigned max[2];
          max[0] = max[1] = h->picture_structure == PICT_FRAME ? 15 : 31;
  
          if (sl->slice_type_nos == AV_PICTURE_TYPE_B)
              sl->direct_spatial_mv_pred = get_bits1(&sl->gb);
          num_ref_idx_active_override_flag = get_bits1(&sl->gb);
  
          if (num_ref_idx_active_override_flag) {
              ref_count[0] = get_ue_golomb(&sl->gb) + 1;
              if (sl->slice_type_nos == AV_PICTURE_TYPE_B) {
                  ref_count[1] = get_ue_golomb(&sl->gb) + 1;
              } else
                  // full range is spec-ok in this case, even for frames
                  ref_count[1] = 1;
          }
  
          if (ref_count[0]-1 > max[0] || ref_count[1]-1 > max[1]){
              av_log(h->avctx, AV_LOG_ERROR, "reference overflow %u > %u or %u > %u\n", ref_count[0]-1, max[0], ref_count[1]-1, max[1]);
              sl->ref_count[0] = sl->ref_count[1] = 0;
              sl->list_count   = 0;
              return AVERROR_INVALIDDATA;
          }
  
          if (sl->slice_type_nos == AV_PICTURE_TYPE_B)
              list_count = 2;
          else
              list_count = 1;
      } else {
          list_count   = 0;
          ref_count[0] = ref_count[1] = 0;
      }
  
      if (list_count   != sl->list_count   ||
          ref_count[0] != sl->ref_count[0] ||
          ref_count[1] != sl->ref_count[1]) {
          sl->ref_count[0] = ref_count[0];
          sl->ref_count[1] = ref_count[1];
          sl->list_count   = list_count;
          return 1;
      }
  
      return 0;
  }
  
  static const uint8_t start_code[] = { 0x00, 0x00, 0x01 };
  
  static int get_bit_length(H264Context *h, const uint8_t *buf,
                            const uint8_t *ptr, int dst_length,
                            int i, int next_avc)
  {
      if ((h->workaround_bugs & FF_BUG_AUTODETECT) && i + 3 < next_avc &&
          buf[i]     == 0x00 && buf[i + 1] == 0x00 &&
          buf[i + 2] == 0x01 && buf[i + 3] == 0xE0)
          h->workaround_bugs |= FF_BUG_TRUNCATED;
  
      if (!(h->workaround_bugs & FF_BUG_TRUNCATED))
          while (dst_length > 0 && ptr[dst_length - 1] == 0)
              dst_length--;
  
      if (!dst_length)
          return 0;
  
      return 8 * dst_length - decode_rbsp_trailing(h, ptr + dst_length - 1);
  }
  
  static int get_last_needed_nal(H264Context *h, const uint8_t *buf, int buf_size)
  {
      int next_avc    = h->is_avc ? 0 : buf_size;
      int nal_index   = 0;
      int buf_index   = 0;
      int nals_needed = 0;
      int first_slice = 0;
  
      while(1) {
          GetBitContext gb;
          int nalsize = 0;
          int dst_length, bit_length, consumed;
          const uint8_t *ptr;
  
          if (buf_index >= next_avc) {
              nalsize = get_avc_nalsize(h, buf, buf_size, &buf_index);
              if (nalsize < 0)
                  break;
              next_avc = buf_index + nalsize;
          } else {
              buf_index = find_start_code(buf, buf_size, buf_index, next_avc);
              if (buf_index >= buf_size)
                  break;
              if (buf_index >= next_avc)
                  continue;
          }
  
          ptr = ff_h264_decode_nal(h, &h->slice_ctx[0], buf + buf_index, &dst_length, &consumed,
                                   next_avc - buf_index);
  
          if (!ptr || dst_length < 0)
              return AVERROR_INVALIDDATA;
  
          buf_index += consumed;
  
          bit_length = get_bit_length(h, buf, ptr, dst_length,
                                      buf_index, next_avc);
          nal_index++;
  
          /* packets can sometimes contain multiple PPS/SPS,
           * e.g. two PAFF field pictures in one packet, or a demuxer
           * which splits NALs strangely if so, when frame threading we
           * can't start the next thread until we've read all of them */
          switch (h->nal_unit_type) {
          case NAL_SPS:
          case NAL_PPS:
              nals_needed = nal_index;
              break;
          case NAL_DPA:
          case NAL_IDR_SLICE:
          case NAL_SLICE:
              init_get_bits(&gb, ptr, bit_length);
              if (!get_ue_golomb(&gb) ||
                  !first_slice ||
                  first_slice != h->nal_unit_type)
                  nals_needed = nal_index;
              if (!first_slice)
                  first_slice = h->nal_unit_type;
          }
      }
  
      return nals_needed;
  }
  
  static int decode_nal_units(H264Context *h, const uint8_t *buf, int buf_size,
                              int parse_extradata)
  {
      AVCodecContext *const avctx = h->avctx;
      H264SliceContext *sl;
      int buf_index;
      unsigned context_count;
      int next_avc;
      int nals_needed = 0; ///< number of NALs that need decoding before the next frame thread starts
      int nal_index;
      int idr_cleared=0;
      int ret = 0;
  
      h->nal_unit_type= 0;
  
      if(!h->slice_context_count)
           h->slice_context_count= 1;
      h->max_contexts = h->slice_context_count;
      if (!(avctx->flags2 & AV_CODEC_FLAG2_CHUNKS)) {
          h->current_slice = 0;
          if (!h->first_field)
              h->cur_pic_ptr = NULL;
          ff_h264_reset_sei(h);
      }
  
      if (h->nal_length_size == 4) {
          if (buf_size > 8 && AV_RB32(buf) == 1 && AV_RB32(buf+5) > (unsigned)buf_size) {
              h->is_avc = 0;
          }else if(buf_size > 3 && AV_RB32(buf) > 1 && AV_RB32(buf) <= (unsigned)buf_size)
              h->is_avc = 1;
      }
  
      if (avctx->active_thread_type & FF_THREAD_FRAME)
          nals_needed = get_last_needed_nal(h, buf, buf_size);
  
      {
          buf_index     = 0;
          context_count = 0;
          next_avc      = h->is_avc ? 0 : buf_size;
          nal_index     = 0;
          for (;;) {
              int consumed;
              int dst_length;
              int bit_length;
              const uint8_t *ptr;
              int nalsize = 0;
              int err;
  
              if (buf_index >= next_avc) {
                  nalsize = get_avc_nalsize(h, buf, buf_size, &buf_index);
                  if (nalsize < 0)
                      break;
                  next_avc = buf_index + nalsize;
              } else {
                  buf_index = find_start_code(buf, buf_size, buf_index, next_avc);
                  if (buf_index >= buf_size)
                      break;
                  if (buf_index >= next_avc)
                      continue;
              }
  
              sl = &h->slice_ctx[context_count];
  
              ptr = ff_h264_decode_nal(h, sl, buf + buf_index, &dst_length,
                                       &consumed, next_avc - buf_index);
              if (!ptr || dst_length < 0) {
                  ret = -1;
                  goto end;
              }
  
              bit_length = get_bit_length(h, buf, ptr, dst_length,
                                          buf_index + consumed, next_avc);
  
              if (h->avctx->debug & FF_DEBUG_STARTCODE)
                  av_log(h->avctx, AV_LOG_DEBUG,
                         "NAL %d/%d at %d/%d length %d\n",
                         h->nal_unit_type, h->nal_ref_idc, buf_index, buf_size, dst_length);
  
              if (h->is_avc && (nalsize != consumed) && nalsize)
                  av_log(h->avctx, AV_LOG_DEBUG,
                         "AVC: Consumed only %d bytes instead of %d\n",
                         consumed, nalsize);
  
              buf_index += consumed;
              nal_index++;
  
              if (avctx->skip_frame >= AVDISCARD_NONREF &&
                  h->nal_ref_idc == 0 &&
                  h->nal_unit_type != NAL_SEI)
                  continue;
  
  again:
              /* Ignore per frame NAL unit type during extradata
               * parsing. Decoding slices is not possible in codec init
               * with frame-mt */
              if (parse_extradata) {
                  switch (h->nal_unit_type) {
                  case NAL_IDR_SLICE:
                  case NAL_SLICE:
                  case NAL_DPA:
                  case NAL_DPB:
                  case NAL_DPC:
                      av_log(h->avctx, AV_LOG_WARNING,
                             "Ignoring NAL %d in global header/extradata\n",
                             h->nal_unit_type);
                      // fall through to next case
                  case NAL_AUXILIARY_SLICE:
                      h->nal_unit_type = NAL_FF_IGNORE;
                  }
              }
  
              err = 0;
  
              switch (h->nal_unit_type) {
              case NAL_IDR_SLICE:
                  if ((ptr[0] & 0xFC) == 0x98) {
                      av_log(h->avctx, AV_LOG_ERROR, "Invalid inter IDR frame\n");
                      h->next_outputed_poc = INT_MIN;
                      ret = -1;
                      goto end;
                  }
                  if (h->nal_unit_type != NAL_IDR_SLICE) {
                      av_log(h->avctx, AV_LOG_ERROR,
                             "Invalid mix of idr and non-idr slices\n");
                      ret = -1;
                      goto end;
                  }
                  if(!idr_cleared) {
                      if (h->current_slice && (avctx->active_thread_type & FF_THREAD_SLICE)) {
                          av_log(h, AV_LOG_ERROR, "invalid mixed IDR / non IDR frames cannot be decoded in slice multithreading mode\n");
                          ret = AVERROR_INVALIDDATA;
                          goto end;
                      }
                      idr(h); // FIXME ensure we don't lose some frames if there is reordering
                  }
                  idr_cleared = 1;
                  h->has_recovery_point = 1;
              case NAL_SLICE:
                  init_get_bits(&sl->gb, ptr, bit_length);
  
                  if (   nals_needed >= nal_index
                      || (!(avctx->active_thread_type & FF_THREAD_FRAME) && !context_count))
                      h->au_pps_id = -1;
  
                  if ((err = ff_h264_decode_slice_header(h, sl)))
                      break;
  
                  if (h->sei_recovery_frame_cnt >= 0) {
                      if (h->frame_num != h->sei_recovery_frame_cnt || sl->slice_type_nos != AV_PICTURE_TYPE_I)
                          h->valid_recovery_point = 1;
  
                      if (   h->recovery_frame < 0
                          || av_mod_uintp2(h->recovery_frame - h->frame_num, h->sps.log2_max_frame_num) > h->sei_recovery_frame_cnt) {
                          h->recovery_frame = av_mod_uintp2(h->frame_num + h->sei_recovery_frame_cnt, h->sps.log2_max_frame_num);
  
                          if (!h->valid_recovery_point)
                              h->recovery_frame = h->frame_num;
                      }
                  }
  
                  h->cur_pic_ptr->f->key_frame |=
                      (h->nal_unit_type == NAL_IDR_SLICE);
  
                  if (h->nal_unit_type == NAL_IDR_SLICE ||
                      h->recovery_frame == h->frame_num) {
                      h->recovery_frame         = -1;
                      h->cur_pic_ptr->recovered = 1;
                  }
                  // If we have an IDR, all frames after it in decoded order are
                  // "recovered".
                  if (h->nal_unit_type == NAL_IDR_SLICE)
                      h->frame_recovered |= FRAME_RECOVERED_IDR;
                  h->frame_recovered |= 3*!!(avctx->flags2 & AV_CODEC_FLAG2_SHOW_ALL);
                  h->frame_recovered |= 3*!!(avctx->flags & AV_CODEC_FLAG_OUTPUT_CORRUPT);
  #if 1
                  h->cur_pic_ptr->recovered |= h->frame_recovered;
  #else
                  h->cur_pic_ptr->recovered |= !!(h->frame_recovered & FRAME_RECOVERED_IDR);
  #endif
  
                  if (h->current_slice == 1) {
                      if (!(avctx->flags2 & AV_CODEC_FLAG2_CHUNKS))
                          decode_postinit(h, nal_index >= nals_needed);
  
                      if (h->avctx->hwaccel &&
                          (ret = h->avctx->hwaccel->start_frame(h->avctx, buf, buf_size)) < 0)
                          goto end;
  #if FF_API_CAP_VDPAU
                      if (CONFIG_H264_VDPAU_DECODER &&
                          h->avctx->codec->capabilities & AV_CODEC_CAP_HWACCEL_VDPAU)
                          ff_vdpau_h264_picture_start(h);
  #endif
                  }
  
                  if (sl->redundant_pic_count == 0) {
                      if (avctx->hwaccel) {
                          ret = avctx->hwaccel->decode_slice(avctx,
                                                             &buf[buf_index - consumed],
                                                             consumed);
                          if (ret < 0)
                              goto end;
  #if FF_API_CAP_VDPAU
                      } else if (CONFIG_H264_VDPAU_DECODER &&
                                 h->avctx->codec->capabilities & AV_CODEC_CAP_HWACCEL_VDPAU) {
                          ff_vdpau_add_data_chunk(h->cur_pic_ptr->f->data[0],
                                                  start_code,
                                                  sizeof(start_code));
                          ff_vdpau_add_data_chunk(h->cur_pic_ptr->f->data[0],
                                                  &buf[buf_index - consumed],
                                                  consumed);
  #endif
                      } else
                          context_count++;
                  }
                  break;
              case NAL_DPA:
              case NAL_DPB:
              case NAL_DPC:
                  avpriv_request_sample(avctx, "data partitioning");
                  break;
              case NAL_SEI:
                  init_get_bits(&h->gb, ptr, bit_length);
                  ret = ff_h264_decode_sei(h);
                  if (ret < 0 && (h->avctx->err_recognition & AV_EF_EXPLODE))
                      goto end;
                  break;
              case NAL_SPS:
                  init_get_bits(&h->gb, ptr, bit_length);
                  if (ff_h264_decode_seq_parameter_set(h, 0) >= 0)
                      break;
                  if (h->is_avc ? nalsize : 1) {
                      av_log(h->avctx, AV_LOG_DEBUG,
                             "SPS decoding failure, trying again with the complete NAL\n");
                      if (h->is_avc)
                          av_assert0(next_avc - buf_index + consumed == nalsize);
                      if ((next_avc - buf_index + consumed - 1) >= INT_MAX/8)
                          break;
                      init_get_bits(&h->gb, &buf[buf_index + 1 - consumed],
                                    8*(next_avc - buf_index + consumed - 1));
                      if (ff_h264_decode_seq_parameter_set(h, 0) >= 0)
                          break;
                  }
                  init_get_bits(&h->gb, ptr, bit_length);
                  ff_h264_decode_seq_parameter_set(h, 1);
  
                  break;
              case NAL_PPS:
                  init_get_bits(&h->gb, ptr, bit_length);
                  ret = ff_h264_decode_picture_parameter_set(h, bit_length);
                  if (ret < 0 && (h->avctx->err_recognition & AV_EF_EXPLODE))
                      goto end;
                  break;
              case NAL_AUD:
              case NAL_END_SEQUENCE:
              case NAL_END_STREAM:
              case NAL_FILLER_DATA:
              case NAL_SPS_EXT:
              case NAL_AUXILIARY_SLICE:
                  break;
              case NAL_FF_IGNORE:
                  break;
              default:
                  av_log(avctx, AV_LOG_DEBUG, "Unknown NAL code: %d (%d bits)\n",
                         h->nal_unit_type, bit_length);
              }
  
              if (context_count == h->max_contexts) {
                  ret = ff_h264_execute_decode_slices(h, context_count);
                  if (ret < 0 && (h->avctx->err_recognition & AV_EF_EXPLODE))
                      goto end;
                  context_count = 0;
              }
  
              if (err < 0 || err == SLICE_SKIPED) {
                  if (err < 0)
                      av_log(h->avctx, AV_LOG_ERROR, "decode_slice_header error\n");
                  sl->ref_count[0] = sl->ref_count[1] = sl->list_count = 0;
              } else if (err == SLICE_SINGLETHREAD) {
                  if (context_count > 1) {
                      ret = ff_h264_execute_decode_slices(h, context_count - 1);
                      if (ret < 0 && (h->avctx->err_recognition & AV_EF_EXPLODE))
                          goto end;
                      context_count = 0;
                  }
                  /* Slice could not be decoded in parallel mode, restart. Note
                   * that rbsp_buffer is not transferred, but since we no longer
                   * run in parallel mode this should not be an issue. */
                  sl               = &h->slice_ctx[0];
                  goto again;
              }
          }
      }
      if (context_count) {
          ret = ff_h264_execute_decode_slices(h, context_count);
          if (ret < 0 && (h->avctx->err_recognition & AV_EF_EXPLODE))
              goto end;
      }
  
      ret = 0;
  end:
      /* clean up */
      if (h->cur_pic_ptr && !h->droppable) {
          ff_thread_report_progress(&h->cur_pic_ptr->tf, INT_MAX,
                                    h->picture_structure == PICT_BOTTOM_FIELD);
      }
  
      return (ret < 0) ? ret : buf_index;
  }
  
  /**
   * Return the number of bytes consumed for building the current frame.
   */
  static int get_consumed_bytes(int pos, int buf_size)
  {
      if (pos == 0)
          pos = 1;        // avoid infinite loops (I doubt that is needed but...)
      if (pos + 10 > buf_size)
          pos = buf_size; // oops ;)
  
      return pos;
  }
  
  static int output_frame(H264Context *h, AVFrame *dst, H264Picture *srcp)
  {
      AVFrame *src = srcp->f;
      const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(src->format);
      int i;
      int ret = av_frame_ref(dst, src);
      if (ret < 0)
          return ret;
  
      av_dict_set(&dst->metadata, "stereo_mode", ff_h264_sei_stereo_mode(h), 0);
  
      h->backup_width   = h->avctx->width;
      h->backup_height  = h->avctx->height;
      h->backup_pix_fmt = h->avctx->pix_fmt;
  
      h->avctx->width   = dst->width;
      h->avctx->height  = dst->height;
      h->avctx->pix_fmt = dst->format;
  
      if (srcp->sei_recovery_frame_cnt == 0)
          dst->key_frame = 1;
      if (!srcp->crop)
          return 0;
  
      for (i = 0; i < desc->nb_components; i++) {
          int hshift = (i > 0) ? desc->log2_chroma_w : 0;
          int vshift = (i > 0) ? desc->log2_chroma_h : 0;
          int off    = ((srcp->crop_left >> hshift) << h->pixel_shift) +
                        (srcp->crop_top  >> vshift) * dst->linesize[i];
          dst->data[i] += off;
      }
      return 0;
  }
  
  static int is_extra(const uint8_t *buf, int buf_size)
  {
      int cnt= buf[5]&0x1f;
      const uint8_t *p= buf+6;
      while(cnt--){
          int nalsize= AV_RB16(p) + 2;
          if(nalsize > buf_size - (p-buf) || p[2]!=0x67)
              return 0;
          p += nalsize;
      }
      cnt = *(p++);
      if(!cnt)
          return 0;
      while(cnt--){
          int nalsize= AV_RB16(p) + 2;
          if(nalsize > buf_size - (p-buf) || p[2]!=0x68)
              return 0;
          p += nalsize;
      }
      return 1;
  }
  
  static int h264_decode_frame(AVCodecContext *avctx, void *data,
                               int *got_frame, AVPacket *avpkt)
  {
      const uint8_t *buf = avpkt->data;
      int buf_size       = avpkt->size;
      H264Context *h     = avctx->priv_data;
      AVFrame *pict      = data;
      int buf_index      = 0;
      H264Picture *out;
      int i, out_idx;
      int ret;
  
      h->flags = avctx->flags;
      h->setup_finished = 0;
  
      if (h->backup_width != -1) {
          avctx->width    = h->backup_width;
          h->backup_width = -1;
      }
      if (h->backup_height != -1) {
          avctx->height    = h->backup_height;
          h->backup_height = -1;
      }
      if (h->backup_pix_fmt != AV_PIX_FMT_NONE) {
          avctx->pix_fmt    = h->backup_pix_fmt;
          h->backup_pix_fmt = AV_PIX_FMT_NONE;
      }
  
      ff_h264_unref_picture(h, &h->last_pic_for_ec);
  
      /* end of stream, output what is still in the buffers */
      if (buf_size == 0) {
   out:
  
          h->cur_pic_ptr = NULL;
          h->first_field = 0;
  
          // FIXME factorize this with the output code below
          out     = h->delayed_pic[0];
          out_idx = 0;
          for (i = 1;
               h->delayed_pic[i] &&
               !h->delayed_pic[i]->f->key_frame &&
               !h->delayed_pic[i]->mmco_reset;
               i++)
              if (h->delayed_pic[i]->poc < out->poc) {
                  out     = h->delayed_pic[i];
                  out_idx = i;
              }
  
          for (i = out_idx; h->delayed_pic[i]; i++)
              h->delayed_pic[i] = h->delayed_pic[i + 1];
  
          if (out) {
              out->reference &= ~DELAYED_PIC_REF;
              ret = output_frame(h, pict, out);
              if (ret < 0)
                  return ret;
              *got_frame = 1;
          }
  
          return buf_index;
      }
      if (h->is_avc && av_packet_get_side_data(avpkt, AV_PKT_DATA_NEW_EXTRADATA, NULL)) {
          int side_size;
          uint8_t *side = av_packet_get_side_data(avpkt, AV_PKT_DATA_NEW_EXTRADATA, &side_size);
          if (is_extra(side, side_size))
              ff_h264_decode_extradata(h, side, side_size);
      }
      if(h->is_avc && buf_size >= 9 && buf[0]==1 && buf[2]==0 && (buf[4]&0xFC)==0xFC && (buf[5]&0x1F) && buf[8]==0x67){
          if (is_extra(buf, buf_size))
              return ff_h264_decode_extradata(h, buf, buf_size);
      }
  
      buf_index = decode_nal_units(h, buf, buf_size, 0);
      if (buf_index < 0)
          return AVERROR_INVALIDDATA;
  
      if (!h->cur_pic_ptr && h->nal_unit_type == NAL_END_SEQUENCE) {
          av_assert0(buf_index <= buf_size);
          goto out;
      }
  
      if (!(avctx->flags2 & AV_CODEC_FLAG2_CHUNKS) && !h->cur_pic_ptr) {
          if (avctx->skip_frame >= AVDISCARD_NONREF ||
              buf_size >= 4 && !memcmp("Q264", buf, 4))
              return buf_size;
          av_log(avctx, AV_LOG_ERROR, "no frame!\n");
          return AVERROR_INVALIDDATA;
      }
  
      if (!(avctx->flags2 & AV_CODEC_FLAG2_CHUNKS) ||
          (h->mb_y >= h->mb_height && h->mb_height)) {
          if (avctx->flags2 & AV_CODEC_FLAG2_CHUNKS)
              decode_postinit(h, 1);
  
          if ((ret = ff_h264_field_end(h, &h->slice_ctx[0], 0)) < 0)
              return ret;
  
          /* Wait for second field. */
          *got_frame = 0;
          if (h->next_output_pic && (
                                     h->next_output_pic->recovered)) {
              if (!h->next_output_pic->recovered)
                  h->next_output_pic->f->flags |= AV_FRAME_FLAG_CORRUPT;
  
              if (!h->avctx->hwaccel &&
                   (h->next_output_pic->field_poc[0] == INT_MAX ||
                    h->next_output_pic->field_poc[1] == INT_MAX)
              ) {
                  int p;
                  AVFrame *f = h->next_output_pic->f;
                  int field = h->next_output_pic->field_poc[0] == INT_MAX;
                  uint8_t *dst_data[4];
                  int linesizes[4];
                  const uint8_t *src_data[4];
  
                  av_log(h->avctx, AV_LOG_DEBUG, "Duplicating field %d to fill missing\n", field);
  
                  for (p = 0; p<4; p++) {
                      dst_data[p] = f->data[p] + (field^1)*f->linesize[p];
                      src_data[p] = f->data[p] +  field   *f->linesize[p];
                      linesizes[p] = 2*f->linesize[p];
                  }
  
                  av_image_copy(dst_data, linesizes, src_data, linesizes,
                                f->format, f->width, f->height>>1);
              }
  
              ret = output_frame(h, pict, h->next_output_pic);
              if (ret < 0)
                  return ret;
              *got_frame = 1;
              if (CONFIG_MPEGVIDEO) {
                  ff_print_debug_info2(h->avctx, pict, NULL,
                                      h->next_output_pic->mb_type,
                                      h->next_output_pic->qscale_table,
                                      h->next_output_pic->motion_val,
                                      &h->low_delay,
                                      h->mb_width, h->mb_height, h->mb_stride, 1);
              }
          }
      }
  
      av_assert0(pict->buf[0] || !*got_frame);
  
      ff_h264_unref_picture(h, &h->last_pic_for_ec);
  
      return get_consumed_bytes(buf_index, buf_size);
  }
  
  av_cold void ff_h264_free_context(H264Context *h)
  {
      int i;
  
      ff_h264_free_tables(h);
  
      for (i = 0; i < H264_MAX_PICTURE_COUNT; i++) {
          ff_h264_unref_picture(h, &h->DPB[i]);
          av_frame_free(&h->DPB[i].f);
      }
      memset(h->delayed_pic, 0, sizeof(h->delayed_pic));
  
      h->cur_pic_ptr = NULL;
  
      for (i = 0; i < h->nb_slice_ctx; i++)
          av_freep(&h->slice_ctx[i].rbsp_buffer);
      av_freep(&h->slice_ctx);
      h->nb_slice_ctx = 0;
  
      for (i = 0; i < MAX_SPS_COUNT; i++)
          av_freep(h->sps_buffers + i);
  
      for (i = 0; i < MAX_PPS_COUNT; i++)
          av_freep(h->pps_buffers + i);
  }
  
  static av_cold int h264_decode_end(AVCodecContext *avctx)
  {
      H264Context *h = avctx->priv_data;
  
      ff_h264_remove_all_refs(h);
      ff_h264_free_context(h);
  
      ff_h264_unref_picture(h, &h->cur_pic);
      av_frame_free(&h->cur_pic.f);
      ff_h264_unref_picture(h, &h->last_pic_for_ec);
      av_frame_free(&h->last_pic_for_ec.f);
  
      return 0;
  }
  
  #define OFFSET(x) offsetof(H264Context, x)
  #define VD AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_DECODING_PARAM
  static const AVOption h264_options[] = {
      {"is_avc", "is avc", offsetof(H264Context, is_avc), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, 0},
      {"nal_length_size", "nal_length_size", offsetof(H264Context, nal_length_size), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 4, 0},
      { "enable_er", "Enable error resilience on damaged frames (unsafe)", OFFSET(enable_er), AV_OPT_TYPE_INT, { .i64 = -1 }, -1, 1, VD },
      { NULL },
  };
  
  static const AVClass h264_class = {
      .class_name = "H264 Decoder",
      .item_name  = av_default_item_name,
      .option     = h264_options,
      .version    = LIBAVUTIL_VERSION_INT,
  };
  
  static const AVProfile profiles[] = {
      { FF_PROFILE_H264_BASELINE,             "Baseline"              },
      { FF_PROFILE_H264_CONSTRAINED_BASELINE, "Constrained Baseline"  },
      { FF_PROFILE_H264_MAIN,                 "Main"                  },
      { FF_PROFILE_H264_EXTENDED,             "Extended"              },
      { FF_PROFILE_H264_HIGH,                 "High"                  },
      { FF_PROFILE_H264_HIGH_10,              "High 10"               },
      { FF_PROFILE_H264_HIGH_10_INTRA,        "High 10 Intra"         },
      { FF_PROFILE_H264_HIGH_422,             "High 4:2:2"            },
      { FF_PROFILE_H264_HIGH_422_INTRA,       "High 4:2:2 Intra"      },
      { FF_PROFILE_H264_HIGH_444,             "High 4:4:4"            },
      { FF_PROFILE_H264_HIGH_444_PREDICTIVE,  "High 4:4:4 Predictive" },
      { FF_PROFILE_H264_HIGH_444_INTRA,       "High 4:4:4 Intra"      },
      { FF_PROFILE_H264_CAVLC_444,            "CAVLC 4:4:4"           },
      { FF_PROFILE_UNKNOWN },
  };
  
  AVCodec ff_h264_decoder = {
      .name                  = "h264",
      .long_name             = NULL_IF_CONFIG_SMALL("H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10"),
      .type                  = AVMEDIA_TYPE_VIDEO,
      .id                    = AV_CODEC_ID_H264,
      .priv_data_size        = sizeof(H264Context),
      .init                  = ff_h264_decode_init,
      .close                 = h264_decode_end,
      .decode                = h264_decode_frame,
      .capabilities          = /*AV_CODEC_CAP_DRAW_HORIZ_BAND |*/ AV_CODEC_CAP_DR1 |
                               AV_CODEC_CAP_DELAY | AV_CODEC_CAP_SLICE_THREADS |
                               AV_CODEC_CAP_FRAME_THREADS,
      .flush                 = flush_dpb,
      .init_thread_copy      = ONLY_IF_THREADS_ENABLED(decode_init_thread_copy),
      .update_thread_context = ONLY_IF_THREADS_ENABLED(ff_h264_update_thread_context),
      .profiles              = NULL_IF_CONFIG_SMALL(profiles),
      .priv_class            = &h264_class,
  };
  
  #if CONFIG_H264_VDPAU_DECODER && FF_API_VDPAU
  static const AVClass h264_vdpau_class = {
      .class_name = "H264 VDPAU Decoder",
      .item_name  = av_default_item_name,
      .option     = h264_options,
      .version    = LIBAVUTIL_VERSION_INT,
  };
  
  AVCodec ff_h264_vdpau_decoder = {
      .name           = "h264_vdpau",
      .long_name      = NULL_IF_CONFIG_SMALL("H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10 (VDPAU acceleration)"),
      .type           = AVMEDIA_TYPE_VIDEO,
      .id             = AV_CODEC_ID_H264,
      .priv_data_size = sizeof(H264Context),
      .init           = ff_h264_decode_init,
      .close          = h264_decode_end,
      .decode         = h264_decode_frame,
      .capabilities   = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_DELAY | AV_CODEC_CAP_HWACCEL_VDPAU,
      .flush          = flush_dpb,
      .pix_fmts       = (const enum AVPixelFormat[]) { AV_PIX_FMT_VDPAU_H264,
                                                       AV_PIX_FMT_NONE},
      .profiles       = NULL_IF_CONFIG_SMALL(profiles),
      .priv_class     = &h264_vdpau_class,
  };
  #endif
  