text: /*
   * XVideo Motion Compensation
   * Copyright (c) 2003 Ivan Kalvachev
   *
   * This file is part of Libav.
   *
   * Libav 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.
   *
   * Libav 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 Libav; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
   */
  
  #include <limits.h>
  #include <X11/extensions/XvMC.h>
  
  #include "avcodec.h"
  #include "mpegutils.h"
  #include "mpegvideo.h"
  
  #undef NDEBUG
  #include <assert.h>
  
  #include "xvmc.h"
  #include "xvmc_internal.h"
  #include "version.h"
  
  #if FF_API_XVMC
  
  /**
   * Initialize the block field of the MpegEncContext pointer passed as
   * parameter after making sure that the data is not corrupted.
   * In order to implement something like direct rendering instead of decoding
   * coefficients in s->blocks and then copying them, copy them directly
   * into the data_blocks array provided by xvmc.
   */
  void ff_xvmc_init_block(MpegEncContext *s)
  {
      struct xvmc_pix_fmt *render = (struct xvmc_pix_fmt*)s->current_picture.f->data[2];
      assert(render && render->xvmc_id == AV_XVMC_ID);
  
      s->block = (int16_t (*)[64])(render->data_blocks + render->next_free_data_block_num * 64);
  }
  
  /**
   * Fill individual block pointers, so there are no gaps in the data_block array
   * in case not all blocks in the macroblock are coded.
   */
  void ff_xvmc_pack_pblocks(MpegEncContext *s, int cbp)
  {
      int i, j = 0;
      const int mb_block_count = 4 + (1 << s->chroma_format);
  
      cbp <<= 12-mb_block_count;
      for (i = 0; i < mb_block_count; i++) {
          if (cbp & (1 << 11))
              s->pblocks[i] = &s->block[j++];
          else
              s->pblocks[i] = NULL;
          cbp += cbp;
      }
  }
  
  /**
   * Find and store the surfaces that are used as reference frames.
   * This function should be called for every new field and/or frame.
   * It should be safe to call the function a few times for the same field.
   */
  int ff_xvmc_field_start(MpegEncContext *s, AVCodecContext *avctx)
  {
      struct xvmc_pix_fmt *last, *next, *render = (struct xvmc_pix_fmt*)s->current_picture.f->data[2];
      const int mb_block_count = 4 + (1 << s->chroma_format);
  
      assert(avctx);
      if (!render || render->xvmc_id != AV_XVMC_ID ||
          !render->data_blocks || !render->mv_blocks ||
          (unsigned int)render->allocated_mv_blocks   > INT_MAX/(64*6) ||
          (unsigned int)render->allocated_data_blocks > INT_MAX/64     ||
          !render->p_surface) {
          av_log(avctx, AV_LOG_ERROR,
                 "Render token doesn't look as expected.\n");
          return -1; // make sure that this is a render packet
      }
  
      if (render->filled_mv_blocks_num) {
          av_log(avctx, AV_LOG_ERROR,
                 "Rendering surface contains %i unprocessed blocks.\n",
                 render->filled_mv_blocks_num);
          return -1;
      }
      if (render->allocated_mv_blocks   < 1 ||
          render->allocated_data_blocks <  render->allocated_mv_blocks*mb_block_count ||
          render->start_mv_blocks_num   >= render->allocated_mv_blocks                ||
          render->next_free_data_block_num >
                          render->allocated_data_blocks -
                          mb_block_count*(render->allocated_mv_blocks-render->start_mv_blocks_num)) {
          av_log(avctx, AV_LOG_ERROR,
                 "Rendering surface doesn't provide enough block structures to work with.\n");
          return -1;
      }
  
      render->picture_structure = s->picture_structure;
      render->flags             = s->first_field ? 0 : XVMC_SECOND_FIELD;
      render->p_future_surface  = NULL;
      render->p_past_surface    = NULL;
  
      switch(s->pict_type) {
          case  AV_PICTURE_TYPE_I:
              return 0; // no prediction from other frames
          case  AV_PICTURE_TYPE_B:
              next = (struct xvmc_pix_fmt*)s->next_picture.f->data[2];
              if (!next)
                  return -1;
              if (next->xvmc_id != AV_XVMC_ID)
                  return -1;
              render->p_future_surface = next->p_surface;
              // no return here, going to set forward prediction
          case  AV_PICTURE_TYPE_P:
              last = (struct xvmc_pix_fmt*)s->last_picture.f->data[2];
              if (!last)
                  last = render; // predict second field from the first
              if (last->xvmc_id != AV_XVMC_ID)
                  return -1;
              render->p_past_surface = last->p_surface;
              return 0;
      }
  
  return -1;
  }
  
  /**
   * Complete frame/field rendering by passing any remaining blocks.
   * Normally ff_draw_horiz_band() is called for each slice, however,
   * some leftover blocks, for example from error_resilience(), may remain.
   * It should be safe to call the function a few times for the same field.
   */
  void ff_xvmc_field_end(MpegEncContext *s)
  {
      struct xvmc_pix_fmt *render = (struct xvmc_pix_fmt*)s->current_picture.f->data[2];
      assert(render);
  
      if (render->filled_mv_blocks_num > 0)
          ff_mpeg_draw_horiz_band(s, 0, 0);
  }
  
  /**
   * Synthesize the data needed by XvMC to render one macroblock of data.
   * Fill all relevant fields, if necessary do IDCT.
   */
  void ff_xvmc_decode_mb(MpegEncContext *s)
  {
      XvMCMacroBlock *mv_block;
      struct xvmc_pix_fmt *render;
      int i, cbp, blocks_per_mb;
  
      const int mb_xy = s->mb_y * s->mb_stride + s->mb_x;
  
  
      if (s->encoding) {
          av_log(s->avctx, AV_LOG_ERROR, "XVMC doesn't support encoding!!!\n");
          return;
      }
  
      // from ff_mpv_decode_mb(), update DC predictors for P macroblocks
      if (!s->mb_intra) {
          s->last_dc[0] =
          s->last_dc[1] =
          s->last_dc[2] =  128 << s->intra_dc_precision;
      }
  
      // MC doesn't skip blocks
      s->mb_skipped = 0;
  
  
      // Do I need to export quant when I could not perform postprocessing?
      // Anyway, it doesn't hurt.
      s->current_picture.qscale_table[mb_xy] = s->qscale;
  
      // start of XVMC-specific code
      render = (struct xvmc_pix_fmt*)s->current_picture.f->data[2];
      assert(render);
      assert(render->xvmc_id == AV_XVMC_ID);
      assert(render->mv_blocks);
  
      // take the next free macroblock
      mv_block = &render->mv_blocks[render->start_mv_blocks_num +
                                    render->filled_mv_blocks_num];
  
      mv_block->x        = s->mb_x;
      mv_block->y        = s->mb_y;
      mv_block->dct_type = s->interlaced_dct; // XVMC_DCT_TYPE_FRAME/FIELD;
      if (s->mb_intra) {
          mv_block->macroblock_type = XVMC_MB_TYPE_INTRA; // no MC, all done
      } else {
          mv_block->macroblock_type = XVMC_MB_TYPE_PATTERN;
  
          if (s->mv_dir & MV_DIR_FORWARD) {
              mv_block->macroblock_type |= XVMC_MB_TYPE_MOTION_FORWARD;
              // PMV[n][dir][xy] = mv[dir][n][xy]
              mv_block->PMV[0][0][0] = s->mv[0][0][0];
              mv_block->PMV[0][0][1] = s->mv[0][0][1];
              mv_block->PMV[1][0][0] = s->mv[0][1][0];
              mv_block->PMV[1][0][1] = s->mv[0][1][1];
          }
          if (s->mv_dir & MV_DIR_BACKWARD) {
              mv_block->macroblock_type |= XVMC_MB_TYPE_MOTION_BACKWARD;
              mv_block->PMV[0][1][0] = s->mv[1][0][0];
              mv_block->PMV[0][1][1] = s->mv[1][0][1];
              mv_block->PMV[1][1][0] = s->mv[1][1][0];
              mv_block->PMV[1][1][1] = s->mv[1][1][1];
          }
  
          switch(s->mv_type) {
              case  MV_TYPE_16X16:
                  mv_block->motion_type = XVMC_PREDICTION_FRAME;
                  break;
              case  MV_TYPE_16X8:
                  mv_block->motion_type = XVMC_PREDICTION_16x8;
                  break;
              case  MV_TYPE_FIELD:
                  mv_block->motion_type = XVMC_PREDICTION_FIELD;
                  if (s->picture_structure == PICT_FRAME) {
                      mv_block->PMV[0][0][1] <<= 1;
                      mv_block->PMV[1][0][1] <<= 1;
                      mv_block->PMV[0][1][1] <<= 1;
                      mv_block->PMV[1][1][1] <<= 1;
                  }
                  break;
              case  MV_TYPE_DMV:
                  mv_block->motion_type = XVMC_PREDICTION_DUAL_PRIME;
                  if (s->picture_structure == PICT_FRAME) {
  
                      mv_block->PMV[0][0][0] = s->mv[0][0][0];      // top from top
                      mv_block->PMV[0][0][1] = s->mv[0][0][1] << 1;
  
                      mv_block->PMV[0][1][0] = s->mv[0][0][0];      // bottom from bottom
                      mv_block->PMV[0][1][1] = s->mv[0][0][1] << 1;
  
                      mv_block->PMV[1][0][0] = s->mv[0][2][0];      // dmv00, top from bottom
                      mv_block->PMV[1][0][1] = s->mv[0][2][1] << 1; // dmv01
  
                      mv_block->PMV[1][1][0] = s->mv[0][3][0];      // dmv10, bottom from top
                      mv_block->PMV[1][1][1] = s->mv[0][3][1] << 1; // dmv11
  
                  } else {
                      mv_block->PMV[0][1][0] = s->mv[0][2][0];      // dmv00
                      mv_block->PMV[0][1][1] = s->mv[0][2][1];      // dmv01
                  }
                  break;
              default:
                  assert(0);
          }
  
          mv_block->motion_vertical_field_select = 0;
  
          // set correct field references
          if (s->mv_type == MV_TYPE_FIELD || s->mv_type == MV_TYPE_16X8) {
              mv_block->motion_vertical_field_select |= s->field_select[0][0];
              mv_block->motion_vertical_field_select |= s->field_select[1][0] << 1;
              mv_block->motion_vertical_field_select |= s->field_select[0][1] << 2;
              mv_block->motion_vertical_field_select |= s->field_select[1][1] << 3;
          }
      } // !intra
      // time to handle data blocks
      mv_block->index = render->next_free_data_block_num;
  
      blocks_per_mb = 6;
      if (s->chroma_format >= 2) {
          blocks_per_mb = 4 + (1 << s->chroma_format);
      }
  
      // calculate cbp
      cbp = 0;
      for (i = 0; i < blocks_per_mb; i++) {
          cbp += cbp;
          if (s->block_last_index[i] >= 0)
              cbp++;
      }
  
      if (s->avctx->flags & AV_CODEC_FLAG_GRAY) {
          if (s->mb_intra) {                                   // intra frames are always full chroma blocks
              for (i = 4; i < blocks_per_mb; i++) {
                  memset(s->pblocks[i], 0, sizeof(*s->pblocks[i]));  // so we need to clear them
                  if (!render->unsigned_intra)
                      *s->pblocks[i][0] = 1 << 10;
              }
          } else {
              cbp &= 0xf << (blocks_per_mb - 4);
              blocks_per_mb = 4;                               // luminance blocks only
          }
      }
      mv_block->coded_block_pattern = cbp;
      if (cbp == 0)
          mv_block->macroblock_type &= ~XVMC_MB_TYPE_PATTERN;
  
      for (i = 0; i < blocks_per_mb; i++) {
          if (s->block_last_index[i] >= 0) {
              // I do not have unsigned_intra MOCO to test, hope it is OK.
              if (s->mb_intra && (render->idct || !render->unsigned_intra))
                  *s->pblocks[i][0] -= 1 << 10;
              if (!render->idct) {
                  s->idsp.idct(*s->pblocks[i]);
                  /* It is unclear if MC hardware requires pixel diff values to be
                   * in the range [-255;255]. TODO: Clipping if such hardware is
                   * ever found. As of now it would only be an unnecessary
                   * slowdown. */
              }
              // copy blocks only if the codec doesn't support pblocks reordering
              if (s->avctx->xvmc_acceleration == 1) {
                  memcpy(&render->data_blocks[render->next_free_data_block_num*64],
                         s->pblocks[i], sizeof(*s->pblocks[i]));
              }
              render->next_free_data_block_num++;
          }
      }
      render->filled_mv_blocks_num++;
  
      assert(render->filled_mv_blocks_num     <= render->allocated_mv_blocks);
      assert(render->next_free_data_block_num <= render->allocated_data_blocks);
      /* The above conditions should not be able to fail as long as this function
       * is used and the following 'if ()' automatically calls a callback to free
       * blocks. */
  
  
      if (render->filled_mv_blocks_num == render->allocated_mv_blocks)
          ff_mpeg_draw_horiz_band(s, 0, 0);
  }
  
  #endif /* FF_API_XVMC */
  