text: /*
   * DV decoder
   * Copyright (c) 2002 Fabrice Bellard
   * Copyright (c) 2004 Roman Shaposhnik
   *
   * 50 Mbps (DVCPRO50) support
   * Copyright (c) 2006 Daniel Maas <dmaas@maasdigital.com>
   *
   * 100 Mbps (DVCPRO HD) support
   * Initial code by Daniel Maas <dmaas@maasdigital.com> (funded by BBC R&D)
   * Final code by Roman Shaposhnik
   *
   * Many thanks to Dan Dennedy <dan@dennedy.org> for providing wealth
   * of DV technical info.
   *
   * 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
   * DV decoder
   */
  
  #include "libavutil/avassert.h"
  #include "libavutil/imgutils.h"
  #include "libavutil/internal.h"
  #include "libavutil/pixdesc.h"
  
  #include "avcodec.h"
  #include "dv.h"
  #include "dv_profile_internal.h"
  #include "dvdata.h"
  #include "get_bits.h"
  #include "idctdsp.h"
  #include "internal.h"
  #include "put_bits.h"
  #include "simple_idct.h"
  
  typedef struct BlockInfo {
      const uint32_t *factor_table;
      const uint8_t *scan_table;
      uint8_t pos; /* position in block */
      void (*idct_put)(uint8_t *dest, int line_size, int16_t *block);
      uint8_t partial_bit_count;
      uint32_t partial_bit_buffer;
      int shift_offset;
  } BlockInfo;
  
  static const int dv_iweight_bits = 14;
  
  static const uint16_t dv_iweight_88[64] = {
      32768, 16705, 16705, 17734, 17032, 17734, 18205, 18081,
      18081, 18205, 18725, 18562, 19195, 18562, 18725, 19266,
      19091, 19705, 19705, 19091, 19266, 21407, 19643, 20267,
      20228, 20267, 19643, 21407, 22725, 21826, 20853, 20806,
      20806, 20853, 21826, 22725, 23170, 23170, 21407, 21400,
      21407, 23170, 23170, 24598, 23786, 22018, 22018, 23786,
      24598, 25251, 24465, 22654, 24465, 25251, 25972, 25172,
      25172, 25972, 26722, 27969, 26722, 29692, 29692, 31521,
  };
  static const uint16_t dv_iweight_248[64] = {
      32768, 16384, 16705, 16705, 17734, 17734, 17734, 17734,
      18081, 18081, 18725, 18725, 21407, 21407, 19091, 19091,
      19195, 19195, 18205, 18205, 18725, 18725, 19705, 19705,
      20267, 20267, 21826, 21826, 23170, 23170, 20806, 20806,
      20267, 20267, 19266, 19266, 21407, 21407, 20853, 20853,
      21400, 21400, 23786, 23786, 24465, 24465, 22018, 22018,
      23170, 23170, 22725, 22725, 24598, 24598, 24465, 24465,
      25172, 25172, 27969, 27969, 25972, 25972, 29692, 29692
  };
  
  /**
   * The "inverse" DV100 weights are actually just the spec weights (zig-zagged).
   */
  static const uint16_t dv_iweight_1080_y[64] = {
      128,  16,  16,  17,  17,  17,  18,  18,
       18,  18,  18,  18,  19,  18,  18,  19,
       19,  19,  19,  19,  19,  42,  38,  40,
       40,  40,  38,  42,  44,  43,  41,  41,
       41,  41,  43,  44,  45,  45,  42,  42,
       42,  45,  45,  48,  46,  43,  43,  46,
       48,  49,  48,  44,  48,  49, 101,  98,
       98, 101, 104, 109, 104, 116, 116, 123,
  };
  static const uint16_t dv_iweight_1080_c[64] = {
      128,  16,  16,  17,  17,  17,  25,  25,
       25,  25,  26,  25,  26,  25,  26,  26,
       26,  27,  27,  26,  26,  42,  38,  40,
       40,  40,  38,  42,  44,  43,  41,  41,
       41,  41,  43,  44,  91,  91,  84,  84,
       84,  91,  91,  96,  93,  86,  86,  93,
       96, 197, 191, 177, 191, 197, 203, 197,
      197, 203, 209, 219, 209, 232, 232, 246,
  };
  static const uint16_t dv_iweight_720_y[64] = {
      128,  16,  16,  17,  17,  17,  18,  18,
       18,  18,  18,  18,  19,  18,  18,  19,
       19,  19,  19,  19,  19,  42,  38,  40,
       40,  40,  38,  42,  44,  43,  41,  41,
       41,  41,  43,  44,  68,  68,  63,  63,
       63,  68,  68,  96,  92,  86,  86,  92,
       96,  98,  96,  88,  96,  98, 202, 196,
      196, 202, 208, 218, 208, 232, 232, 246,
  };
  static const uint16_t dv_iweight_720_c[64] = {
      128,  24,  24,  26,  26,  26,  36,  36,
       36,  36,  36,  36,  38,  36,  36,  38,
       38,  38,  38,  38,  38,  84,  76,  80,
       80,  80,  76,  84,  88,  86,  82,  82,
       82,  82,  86,  88, 182, 182, 168, 168,
      168, 182, 182, 192, 186, 192, 172, 186,
      192, 394, 382, 354, 382, 394, 406, 394,
      394, 406, 418, 438, 418, 464, 464, 492,
  };
  
  static void dv_init_weight_tables(DVVideoContext *ctx, const AVDVProfile *d)
  {
      int j, i, c, s;
      uint32_t *factor1 = &ctx->idct_factor[0],
               *factor2 = &ctx->idct_factor[DV_PROFILE_IS_HD(d) ? 4096 : 2816];
  
      if (DV_PROFILE_IS_HD(d)) {
          /* quantization quanta by QNO for DV100 */
          static const uint8_t dv100_qstep[16] = {
              1, /* QNO = 0 and 1 both have no quantization */
              1,
              2, 3, 4, 5, 6, 7, 8, 16, 18, 20, 22, 24, 28, 52
          };
          const uint16_t *iweight1, *iweight2;
  
          if (d->height == 720) {
              iweight1 = &dv_iweight_720_y[0];
              iweight2 = &dv_iweight_720_c[0];
          } else {
              iweight1 = &dv_iweight_1080_y[0];
              iweight2 = &dv_iweight_1080_c[0];
          }
          for (c = 0; c < 4; c++) {
              for (s = 0; s < 16; s++) {
                  for (i = 0; i < 64; i++) {
                      *factor1++ = (dv100_qstep[s] << (c + 9)) * iweight1[i];
                      *factor2++ = (dv100_qstep[s] << (c + 9)) * iweight2[i];
                  }
              }
          }
      } else {
          static const uint8_t dv_quant_areas[4] = { 6, 21, 43, 64 };
          const uint16_t *iweight1 = &dv_iweight_88[0];
          for (j = 0; j < 2; j++, iweight1 = &dv_iweight_248[0]) {
              for (s = 0; s < 22; s++) {
                  for (i = c = 0; c < 4; c++) {
                      for (; i < dv_quant_areas[c]; i++) {
                          *factor1   = iweight1[i] << (ff_dv_quant_shifts[s][c] + 1);
                          *factor2++ = (*factor1++) << 1;
                      }
                  }
              }
          }
      }
  }
  
  static av_cold int dvvideo_decode_init(AVCodecContext *avctx)
  {
      DVVideoContext *s = avctx->priv_data;
      IDCTDSPContext idsp;
      int i;
  
      memset(&idsp,0, sizeof(idsp));
      ff_idctdsp_init(&idsp, avctx);
  
      for (i = 0; i < 64; i++)
          s->dv_zigzag[0][i] = idsp.idct_permutation[ff_zigzag_direct[i]];
  
      if (avctx->lowres){
          for (i = 0; i < 64; i++){
              int j = ff_dv_zigzag248_direct[i];
              s->dv_zigzag[1][i] = idsp.idct_permutation[(j & 7) + (j & 8) * 4 + (j & 48) / 2];
          }
      }else
          memcpy(s->dv_zigzag[1], ff_dv_zigzag248_direct, sizeof(s->dv_zigzag[1]));
  
      s->idct_put[0] = idsp.idct_put;
      s->idct_put[1] = ff_simple_idct248_put;
  
      return ff_dvvideo_init(avctx);
  }
  
  /* decode AC coefficients */
  static void dv_decode_ac(GetBitContext *gb, BlockInfo *mb, int16_t *block)
  {
      int last_index = gb->size_in_bits;
      const uint8_t  *scan_table   = mb->scan_table;
      const uint32_t *factor_table = mb->factor_table;
      int pos                      = mb->pos;
      int partial_bit_count        = mb->partial_bit_count;
      int level, run, vlc_len, index;
  
      OPEN_READER_NOSIZE(re, gb);
      UPDATE_CACHE(re, gb);
  
      /* if we must parse a partial VLC, we do it here */
      if (partial_bit_count > 0) {
          re_cache              = re_cache >> partial_bit_count |
                                  mb->partial_bit_buffer;
          re_index             -= partial_bit_count;
          mb->partial_bit_count = 0;
      }
  
      /* get the AC coefficients until last_index is reached */
      for (;;) {
          ff_dlog(NULL, "%2d: bits=%04x index=%d\n", pos, SHOW_UBITS(re, gb, 16),
                  re_index);
          /* our own optimized GET_RL_VLC */
          index   = NEG_USR32(re_cache, TEX_VLC_BITS);
          vlc_len = ff_dv_rl_vlc[index].len;
          if (vlc_len < 0) {
              index = NEG_USR32((unsigned) re_cache << TEX_VLC_BITS, -vlc_len) +
                      ff_dv_rl_vlc[index].level;
              vlc_len = TEX_VLC_BITS - vlc_len;
          }
          level = ff_dv_rl_vlc[index].level;
          run   = ff_dv_rl_vlc[index].run;
  
          /* gotta check if we're still within gb boundaries */
          if (re_index + vlc_len > last_index) {
              /* should be < 16 bits otherwise a codeword could have been parsed */
              mb->partial_bit_count  = last_index - re_index;
              mb->partial_bit_buffer = re_cache & ~(-1u >> mb->partial_bit_count);
              re_index               = last_index;
              break;
          }
          re_index += vlc_len;
  
          ff_dlog(NULL, "run=%d level=%d\n", run, level);
          pos += run;
          if (pos >= 64)
              break;
  
          level = (level * factor_table[pos] + (1 << (dv_iweight_bits - 1))) >>
                  dv_iweight_bits;
          block[scan_table[pos]] = level;
  
          UPDATE_CACHE(re, gb);
      }
      CLOSE_READER(re, gb);
      mb->pos = pos;
  }
  
  static inline void bit_copy(PutBitContext *pb, GetBitContext *gb)
  {
      int bits_left = get_bits_left(gb);
      while (bits_left >= MIN_CACHE_BITS) {
          put_bits(pb, MIN_CACHE_BITS, get_bits(gb, MIN_CACHE_BITS));
          bits_left -= MIN_CACHE_BITS;
      }
      if (bits_left > 0)
          put_bits(pb, bits_left, get_bits(gb, bits_left));
  }
  
  /* mb_x and mb_y are in units of 8 pixels */
  static int dv_decode_video_segment(AVCodecContext *avctx, void *arg)
  {
      DVVideoContext *s = avctx->priv_data;
      DVwork_chunk *work_chunk = arg;
      int quant, dc, dct_mode, class1, j;
      int mb_index, mb_x, mb_y, last_index;
      int y_stride, linesize;
      int16_t *block, *block1;
      int c_offset;
      uint8_t *y_ptr;
      const uint8_t *buf_ptr;
      PutBitContext pb, vs_pb;
      GetBitContext gb;
      BlockInfo mb_data[5 * DV_MAX_BPM], *mb, *mb1;
      LOCAL_ALIGNED_16(int16_t, sblock, [5 * DV_MAX_BPM], [64]);
      LOCAL_ALIGNED_16(uint8_t, mb_bit_buffer, [80     + AV_INPUT_BUFFER_PADDING_SIZE]); /* allow some slack */
      LOCAL_ALIGNED_16(uint8_t, vs_bit_buffer, [80 * 5 + AV_INPUT_BUFFER_PADDING_SIZE]); /* allow some slack */
      const int log2_blocksize = 3-s->avctx->lowres;
      int is_field_mode[5];
      int vs_bit_buffer_damaged = 0;
      int mb_bit_buffer_damaged[5] = {0};
      int retried = 0;
      int sta;
  
      av_assert1((((int) mb_bit_buffer) & 7) == 0);
      av_assert1((((int) vs_bit_buffer) & 7) == 0);
  
  retry:
  
      memset(sblock, 0, 5 * DV_MAX_BPM * sizeof(*sblock));
  
      /* pass 1: read DC and AC coefficients in blocks */
      buf_ptr = &s->buf[work_chunk->buf_offset * 80];
      block1  = &sblock[0][0];
      mb1     = mb_data;
      init_put_bits(&vs_pb, vs_bit_buffer, 5 * 80);
      for (mb_index = 0; mb_index < 5; mb_index++, mb1 += s->sys->bpm, block1 += s->sys->bpm * 64) {
          /* skip header */
          quant    = buf_ptr[3] & 0x0f;
          if (avctx->error_concealment) {
              if ((buf_ptr[3] >> 4) == 0x0E)
                  vs_bit_buffer_damaged = 1;
              if (!mb_index) {
                  sta = buf_ptr[3] >> 4;
              } else if (sta != (buf_ptr[3] >> 4))
                  vs_bit_buffer_damaged = 1;
          }
          buf_ptr += 4;
          init_put_bits(&pb, mb_bit_buffer, 80);
          mb    = mb1;
          block = block1;
          is_field_mode[mb_index] = 0;
          for (j = 0; j < s->sys->bpm; j++) {
              last_index = s->sys->block_sizes[j];
              init_get_bits(&gb, buf_ptr, last_index);
  
              /* get the DC */
              dc       = get_sbits(&gb, 9);
              dct_mode = get_bits1(&gb);
              class1   = get_bits(&gb, 2);
              if (DV_PROFILE_IS_HD(s->sys)) {
                  mb->idct_put     = s->idct_put[0];
                  mb->scan_table   = s->dv_zigzag[0];
                  mb->factor_table = &s->idct_factor[(j >= 4) * 4 * 16 * 64 +
                                                     class1       * 16 * 64 +
                                                     quant             * 64];
                  is_field_mode[mb_index] |= !j && dct_mode;
              } else {
                  mb->idct_put     = s->idct_put[dct_mode && log2_blocksize == 3];
                  mb->scan_table   = s->dv_zigzag[dct_mode];
                  mb->factor_table =
                      &s->idct_factor[(class1 == 3)               * 2 * 22 * 64 +
                                      dct_mode                        * 22 * 64 +
                                      (quant + ff_dv_quant_offset[class1]) * 64];
              }
              dc = dc << 2;
              /* convert to unsigned because 128 is not added in the
               * standard IDCT */
              dc                   += 1024;
              block[0]              = dc;
              buf_ptr              += last_index >> 3;
              mb->pos               = 0;
              mb->partial_bit_count = 0;
  
              ff_dlog(avctx, "MB block: %d, %d ", mb_index, j);
              dv_decode_ac(&gb, mb, block);
  
              /* write the remaining bits in a new buffer only if the
               * block is finished */
              if (mb->pos >= 64)
                  bit_copy(&pb, &gb);
              if (mb->pos >= 64 && mb->pos < 127)
                  vs_bit_buffer_damaged = mb_bit_buffer_damaged[mb_index] = 1;
  
              block += 64;
              mb++;
          }
  
          if (mb_bit_buffer_damaged[mb_index] > 0)
              continue;
  
          /* pass 2: we can do it just after */
          ff_dlog(avctx, "***pass 2 size=%d MB#=%d\n", put_bits_count(&pb), mb_index);
          block = block1;
          mb    = mb1;
          init_get_bits(&gb, mb_bit_buffer, put_bits_count(&pb));
          put_bits32(&pb, 0); // padding must be zeroed
          flush_put_bits(&pb);
          for (j = 0; j < s->sys->bpm; j++, block += 64, mb++) {
              if (mb->pos < 64 && get_bits_left(&gb) > 0) {
                  dv_decode_ac(&gb, mb, block);
                  /* if still not finished, no need to parse other blocks */
                  if (mb->pos < 64)
                      break;
                  if (mb->pos < 127)
                      vs_bit_buffer_damaged = mb_bit_buffer_damaged[mb_index] = 1;
              }
          }
          /* all blocks are finished, so the extra bytes can be used at
           * the video segment level */
          if (j >= s->sys->bpm)
              bit_copy(&vs_pb, &gb);
      }
  
      /* we need a pass over the whole video segment */
      ff_dlog(avctx, "***pass 3 size=%d\n", put_bits_count(&vs_pb));
      block = &sblock[0][0];
      mb    = mb_data;
      init_get_bits(&gb, vs_bit_buffer, put_bits_count(&vs_pb));
      put_bits32(&vs_pb, 0); // padding must be zeroed
      flush_put_bits(&vs_pb);
      for (mb_index = 0; mb_index < 5; mb_index++) {
          for (j = 0; j < s->sys->bpm; j++) {
              if (mb->pos < 64 && get_bits_left(&gb) > 0 && !vs_bit_buffer_damaged) {
                  ff_dlog(avctx, "start %d:%d\n", mb_index, j);
                  dv_decode_ac(&gb, mb, block);
              }
  
              if (mb->pos >= 64 && mb->pos < 127) {
                  av_log(avctx, AV_LOG_ERROR,
                         "AC EOB marker is absent pos=%d\n", mb->pos);
                  vs_bit_buffer_damaged = 1;
              }
              block += 64;
              mb++;
          }
      }
      if (vs_bit_buffer_damaged && !retried) {
          av_log(avctx, AV_LOG_ERROR, "Concealing bitstream errors\n");
          retried = 1;
          goto retry;
      }
  
      /* compute idct and place blocks */
      block = &sblock[0][0];
      mb    = mb_data;
      for (mb_index = 0; mb_index < 5; mb_index++) {
          dv_calculate_mb_xy(s, work_chunk, mb_index, &mb_x, &mb_y);
  
          /* idct_put'ting luminance */
          if ((s->sys->pix_fmt == AV_PIX_FMT_YUV420P)                      ||
              (s->sys->pix_fmt == AV_PIX_FMT_YUV411P && mb_x >= (704 / 8)) ||
              (s->sys->height >= 720 && mb_y != 134)) {
              y_stride = (s->frame->linesize[0] <<
                          ((!is_field_mode[mb_index]) * log2_blocksize));
          } else {
              y_stride = (2 << log2_blocksize);
          }
          y_ptr    = s->frame->data[0] +
                     ((mb_y * s->frame->linesize[0] + mb_x) << log2_blocksize);
          linesize = s->frame->linesize[0] << is_field_mode[mb_index];
          mb[0].idct_put(y_ptr, linesize, block + 0 * 64);
          if (s->sys->video_stype == 4) { /* SD 422 */
              mb[2].idct_put(y_ptr + (1 << log2_blocksize),            linesize, block + 2 * 64);
          } else {
              mb[1].idct_put(y_ptr + (1 << log2_blocksize),            linesize, block + 1 * 64);
              mb[2].idct_put(y_ptr                         + y_stride, linesize, block + 2 * 64);
              mb[3].idct_put(y_ptr + (1 << log2_blocksize) + y_stride, linesize, block + 3 * 64);
          }
          mb    += 4;
          block += 4 * 64;
  
          /* idct_put'ting chrominance */
          c_offset = (((mb_y >>  (s->sys->pix_fmt == AV_PIX_FMT_YUV420P)) * s->frame->linesize[1] +
                       (mb_x >> ((s->sys->pix_fmt == AV_PIX_FMT_YUV411P) ? 2 : 1))) << log2_blocksize);
          for (j = 2; j; j--) {
              uint8_t *c_ptr = s->frame->data[j] + c_offset;
              if (s->sys->pix_fmt == AV_PIX_FMT_YUV411P && mb_x >= (704 / 8)) {
                  uint64_t aligned_pixels[64 / 8];
                  uint8_t *pixels = (uint8_t *) aligned_pixels;
                  uint8_t *c_ptr1, *ptr1;
                  int x, y;
                  mb->idct_put(pixels, 8, block);
                  for (y = 0; y < (1 << log2_blocksize); y++, c_ptr += s->frame->linesize[j], pixels += 8) {
                      ptr1   = pixels + ((1 << (log2_blocksize))>>1);
                      c_ptr1 = c_ptr + (s->frame->linesize[j] << log2_blocksize);
                      for (x = 0; x < (1 << FFMAX(log2_blocksize - 1, 0)); x++) {
                          c_ptr[x]  = pixels[x];
                          c_ptr1[x] = ptr1[x];
                      }
                  }
                  block += 64;
                  mb++;
              } else {
                  y_stride = (mb_y == 134) ? (1 << log2_blocksize) :
                             s->frame->linesize[j] << ((!is_field_mode[mb_index]) * log2_blocksize);
                  linesize = s->frame->linesize[j] << is_field_mode[mb_index];
                  (mb++)->idct_put(c_ptr, linesize, block);
                  block += 64;
                  if (s->sys->bpm == 8) {
                      (mb++)->idct_put(c_ptr + y_stride, linesize, block);
                      block += 64;
                  }
              }
          }
      }
      return 0;
  }
  
  /* NOTE: exactly one frame must be given (120000 bytes for NTSC,
   * 144000 bytes for PAL - or twice those for 50Mbps) */
  static int dvvideo_decode_frame(AVCodecContext *avctx, void *data,
                                  int *got_frame, AVPacket *avpkt)
  {
      uint8_t *buf = avpkt->data;
      int buf_size = avpkt->size;
      DVVideoContext *s = avctx->priv_data;
      AVFrame *frame = data;
      const uint8_t *vsc_pack;
      int apt, is16_9, ret;
      const AVDVProfile *sys;
  
      sys = ff_dv_frame_profile(avctx, s->sys, buf, buf_size);
      if (!sys || buf_size < sys->frame_size) {
          av_log(avctx, AV_LOG_ERROR, "could not find dv frame profile\n");
          return -1; /* NOTE: we only accept several full frames */
      }
  
      if (sys != s->sys) {
          ret = ff_dv_init_dynamic_tables(s, sys);
          if (ret < 0) {
              av_log(avctx, AV_LOG_ERROR, "Error initializing the work tables.\n");
              return ret;
          }
          dv_init_weight_tables(s, sys);
          s->sys = sys;
      }
  
      s->frame            = frame;
      frame->key_frame    = 1;
      frame->pict_type    = AV_PICTURE_TYPE_I;
      avctx->pix_fmt      = s->sys->pix_fmt;
      avctx->framerate    = av_inv_q(s->sys->time_base);
  
      ret = ff_set_dimensions(avctx, s->sys->width, s->sys->height);
      if (ret < 0)
          return ret;
  
      /* Determine the codec's sample_aspect ratio from the packet */
      vsc_pack = buf + 80 * 5 + 48 + 5;
      if (*vsc_pack == dv_video_control) {
          apt    = buf[4] & 0x07;
          is16_9 = (vsc_pack[2] & 0x07) == 0x02 ||
                   (!apt && (vsc_pack[2] & 0x07) == 0x07);
          ff_set_sar(avctx, s->sys->sar[is16_9]);
      }
  
      if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
          return ret;
      frame->interlaced_frame = 1;
      frame->top_field_first  = 0;
  
      /* Determine the codec's field order from the packet */
      if ( *vsc_pack == dv_video_control ) {
          frame->top_field_first = !(vsc_pack[3] & 0x40);
      }
  
      s->buf = buf;
      avctx->execute(avctx, dv_decode_video_segment, s->work_chunks, NULL,
                     dv_work_pool_size(s->sys), sizeof(DVwork_chunk));
  
      emms_c();
  
      /* return image */
      *got_frame = 1;
  
      return s->sys->frame_size;
  }
  
  AVCodec ff_dvvideo_decoder = {
      .name           = "dvvideo",
      .long_name      = NULL_IF_CONFIG_SMALL("DV (Digital Video)"),
      .type           = AVMEDIA_TYPE_VIDEO,
      .id             = AV_CODEC_ID_DVVIDEO,
      .priv_data_size = sizeof(DVVideoContext),
      .init           = dvvideo_decode_init,
      .decode         = dvvideo_decode_frame,
      .capabilities   = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_SLICE_THREADS,
      .max_lowres     = 3,
  };
  