/*
  * 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, ptrdiff_t stride, 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=%04"PRIx32" index=%u\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 * 4;

             /* 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,

 };