hvirtual/quicktime/libavcodec/dv.c

   1 /*
   2  * DV decoder
   3  * Copyright (c) 2002 Fabrice Bellard.
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General Public
  16  * License along with this library; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18  */
  19 #include "avcodec.h"
  20 #include "dsputil.h"
  21 #include "mpegvideo.h"
  22 #include "simple_idct.h"
  23
  24 #define NTSC_FRAME_SIZE 120000
  25 #define PAL_FRAME_SIZE  144000
  26
  27 #define TEX_VLC_BITS 9
  28
  29 typedef struct DVVideoDecodeContext {
  30     AVCodecContext *avctx;
  31     GetBitContext gb;
  32     VLC *vlc;
  33     int sampling_411; /* 0 = 420, 1 = 411 */
  34     int width, height;
  35     UINT8 *current_picture[3]; /* picture structure */
  36     AVFrame picture;
  37     int linesize[3];
  38     DCTELEM block[5*6][64] __align8;
  39     UINT8 dv_zigzag[2][64];
  40     UINT8 idct_permutation[64];
  41     /* XXX: move it to static storage ? */
  42     UINT8 dv_shift[2][22][64];
  43     void (*idct_put[2])(UINT8 *dest, int line_size, DCTELEM *block);
  44 } DVVideoDecodeContext;
  45
  46 #include "dvdata.h"
  47
  48 static VLC dv_vlc;
  49 /* XXX: also include quantization */
  50 static RL_VLC_ELEM *dv_rl_vlc[1];
  51
  52 static void dv_build_unquantize_tables(DVVideoDecodeContext *s)
  53 {
  54     int i, q, j;
  55
  56     /* NOTE: max left shift is 6 */
  57     for(q = 0; q < 22; q++) {
  58         /* 88 unquant */
  59         for(i = 1; i < 64; i++) {
  60             /* 88 table */
  61             j = s->idct_permutation[i];
  62             s->dv_shift[0][q][j] =
  63                 dv_quant_shifts[q][dv_88_areas[i]] + 1;
  64         }
  65
  66         /* 248 unquant */
  67         for(i = 1; i < 64; i++) {
  68             /* 248 table */
  69             s->dv_shift[1][q][i] =
  70                     dv_quant_shifts[q][dv_248_areas[i]] + 1;
  71         }
  72     }
  73 }
  74
  75 static int dvvideo_decode_init(AVCodecContext *avctx)
  76 {
  77     DVVideoDecodeContext *s = avctx->priv_data;
  78     MpegEncContext s2;
  79     static int done;
  80
  81     if (!done) {
  82         int i;
  83
  84         done = 1;
  85
  86         /* NOTE: as a trick, we use the fact the no codes are unused
  87            to accelerate the parsing of partial codes */
  88         init_vlc(&dv_vlc, TEX_VLC_BITS, NB_DV_VLC,
  89                  dv_vlc_len, 1, 1, dv_vlc_bits, 2, 2);
  90
  91         dv_rl_vlc[0] = av_malloc(dv_vlc.table_size * sizeof(RL_VLC_ELEM));
  92         for(i = 0; i < dv_vlc.table_size; i++){
  93             int code= dv_vlc.table[i][0];
  94             int len = dv_vlc.table[i][1];
  95             int level, run;
  96
  97             if(len<0){ //more bits needed
  98                 run= 0;
  99                 level= code;
 100             } else if (code == (NB_DV_VLC - 1)) {
 101                 /* EOB */
 102                 run = 0;
 103                 level = 256;
 104             } else {
 105                 run=   dv_vlc_run[code] + 1;
 106                 level= dv_vlc_level[code];
 107             }
 108             dv_rl_vlc[0][i].len = len;
 109             dv_rl_vlc[0][i].level = level;
 110             dv_rl_vlc[0][i].run = run;
 111         }
 112     }
 113
 114     /* ugly way to get the idct & scantable */
 115     /* XXX: fix it */
 116     memset(&s2, 0, sizeof(MpegEncContext));
 117     s2.avctx = avctx;
 118     dsputil_init(&s2.dsp, avctx->dsp_mask);
 119     if (DCT_common_init(&s2) < 0)
 120        return -1;
 121
 122     s->idct_put[0] = s2.idct_put;
 123     memcpy(s->idct_permutation, s2.idct_permutation, 64);
 124     memcpy(s->dv_zigzag[0], s2.intra_scantable.permutated, 64);
 125
 126     /* XXX: use MMX also for idct248 */
 127     s->idct_put[1] = simple_idct248_put;
 128     memcpy(s->dv_zigzag[1], dv_248_zigzag, 64);
 129
 130     /* XXX: do it only for constant case */
 131     dv_build_unquantize_tables(s);
 132
 133     return 0;
 134 }
 135
 136 //#define VLC_DEBUG
 137
 138 typedef struct BlockInfo {
 139     const UINT8 *shift_table;
 140     const UINT8 *scan_table;
 141     UINT8 pos; /* position in block */
 142     UINT8 eob_reached; /* true if EOB has been reached */
 143     UINT8 dct_mode;
 144     UINT8 partial_bit_count;
 145     UINT16 partial_bit_buffer;
 146     int shift_offset;
 147 } BlockInfo;
 148
 149 /* block size in bits */
 150 static const UINT16 block_sizes[6] = {
 151     112, 112, 112, 112, 80, 80
 152 };
 153
 154 #ifndef ALT_BITSTREAM_READER
 155 #error only works with ALT_BITSTREAM_READER
 156 #endif
 157
 158 /* decode ac coefs */
 159 static void dv_decode_ac(DVVideoDecodeContext *s,
 160                          BlockInfo *mb, INT16 *block, int last_index)
 161 {
 162     int last_re_index;
 163     int shift_offset = mb->shift_offset;
 164     const UINT8 *scan_table = mb->scan_table;
 165     const UINT8 *shift_table = mb->shift_table;
 166     int pos = mb->pos;
 167     int level, pos1, sign, run;
 168     int partial_bit_count;
 169
 170     OPEN_READER(re, &s->gb);
 171
 172 #ifdef VLC_DEBUG
 173     printf("start\n");
 174 #endif
 175
 176     /* if we must parse a partial vlc, we do it here */
 177     partial_bit_count = mb->partial_bit_count;
 178     if (partial_bit_count > 0) {
 179         UINT8 buf[4];
 180         UINT32 v;
 181         int l, l1;
 182         GetBitContext gb1;
 183
 184         /* build the dummy bit buffer */
 185         l = 16 - partial_bit_count;
 186         UPDATE_CACHE(re, &s->gb);
 187 #ifdef VLC_DEBUG
 188         printf("show=%04x\n", SHOW_UBITS(re, &s->gb, 16));
 189 #endif
 190         v = (mb->partial_bit_buffer << l) | SHOW_UBITS(re, &s->gb, l);
 191         buf[0] = v >> 8;
 192         buf[1] = v;
 193 #ifdef VLC_DEBUG
 194         printf("v=%04x cnt=%d %04x\n",
 195                v, partial_bit_count, (mb->partial_bit_buffer << l));
 196 #endif
 197         /* try to read the codeword */
 198         init_get_bits(&gb1, buf, 4);
 199         {
 200             OPEN_READER(re1, &gb1);
 201             UPDATE_CACHE(re1, &gb1);
 202             GET_RL_VLC(level, run, re1, &gb1, dv_rl_vlc[0],
 203                        TEX_VLC_BITS, 2);
 204             l = re1_index;
 205             CLOSE_READER(re1, &gb1);
 206         }
 207 #ifdef VLC_DEBUG
 208         printf("****run=%d level=%d size=%d\n", run, level, l);
 209 #endif
 210         /* compute codeword length */
 211         l1 = (level != 256 && level != 0);
 212         /* if too long, we cannot parse */
 213         l -= partial_bit_count;
 214         if ((re_index + l + l1) > last_index)
 215             return;
 216         /* skip read bits */
 217         last_re_index = 0; /* avoid warning */
 218         re_index += l;
 219         /* by definition, if we can read the vlc, all partial bits
 220            will be read (otherwise we could have read the vlc before) */
 221         mb->partial_bit_count = 0;
 222         UPDATE_CACHE(re, &s->gb);
 223         goto handle_vlc;
 224     }
 225
 226     /* get the AC coefficients until last_index is reached */
 227     for(;;) {
 228         UPDATE_CACHE(re, &s->gb);
 229 #ifdef VLC_DEBUG
 230         printf("%2d: bits=%04x index=%d\n",
 231                pos, SHOW_UBITS(re, &s->gb, 16), re_index);
 232 #endif
 233         last_re_index = re_index;
 234         GET_RL_VLC(level, run, re, &s->gb, dv_rl_vlc[0],
 235                    TEX_VLC_BITS, 2);
 236     handle_vlc:
 237 #ifdef VLC_DEBUG
 238         printf("run=%d level=%d\n", run, level);
 239 #endif
 240         if (level == 256) {
 241             if (re_index > last_index) {
 242             cannot_read:
 243                 /* put position before read code */
 244                 re_index = last_re_index;
 245                 mb->eob_reached = 0;
 246                 break;
 247             }
 248             /* EOB */
 249             mb->eob_reached = 1;
 250             break;
 251         } else if (level != 0) {
 252             if ((re_index + 1) > last_index)
 253                 goto cannot_read;
 254             sign = SHOW_SBITS(re, &s->gb, 1);
 255             level = (level ^ sign) - sign;
 256             LAST_SKIP_BITS(re, &s->gb, 1);
 257             pos += run;
 258             /* error */
 259             if (pos >= 64) {
 260                 goto read_error;
 261             }
 262             pos1 = scan_table[pos];
 263             level = level << (shift_table[pos1] + shift_offset);
 264             block[pos1] = level;
 265             //            printf("run=%d level=%d shift=%d\n", run, level, shift_table[pos1]);
 266         } else {
 267             if (re_index > last_index)
 268                 goto cannot_read;
 269             /* level is zero: means run without coding. No
 270                sign is coded */
 271             pos += run;
 272             /* error */
 273             if (pos >= 64) {
 274             read_error:
 275 #if defined(VLC_DEBUG) || 1
 276                 printf("error pos=%d\n", pos);
 277 #endif
 278                 /* for errors, we consider the eob is reached */
 279                 mb->eob_reached = 1;
 280                 break;
 281             }
 282         }
 283     }
 284     CLOSE_READER(re, &s->gb);
 285     mb->pos = pos;
 286 }
 287
 288 static inline void bit_copy(PutBitContext *pb, GetBitContext *gb, int bits_left)
 289 {
 290     while (bits_left >= 16) {
 291         put_bits(pb, 16, get_bits(gb, 16));
 292         bits_left -= 16;
 293     }
 294     if (bits_left > 0) {
 295         put_bits(pb, bits_left, get_bits(gb, bits_left));
 296     }
 297 }
 298
 299 /* mb_x and mb_y are in units of 8 pixels */
 300 static inline void dv_decode_video_segment(DVVideoDecodeContext *s,
 301                                            UINT8 *buf_ptr1,
 302                                            const UINT16 *mb_pos_ptr)
 303 {
 304     int quant, dc, dct_mode, class1, j;
 305     int mb_index, mb_x, mb_y, v, last_index;
 306     DCTELEM *block, *block1;
 307     int c_offset, bits_left;
 308     UINT8 *y_ptr;
 309     BlockInfo mb_data[5 * 6], *mb, *mb1;
 310     void (*idct_put)(UINT8 *dest, int line_size, DCTELEM *block);
 311     UINT8 *buf_ptr;
 312     PutBitContext pb, vs_pb;
 313     UINT8 mb_bit_buffer[80 + 4]; /* allow some slack */
 314     int mb_bit_count;
 315     UINT8 vs_bit_buffer[5 * 80 + 4]; /* allow some slack */
 316     int vs_bit_count;
 317
 318     memset(s->block, 0, sizeof(s->block));
 319
 320     /* pass 1 : read DC and AC coefficients in blocks */
 321     buf_ptr = buf_ptr1;
 322     block1 = &s->block[0][0];
 323     mb1 = mb_data;
 324     init_put_bits(&vs_pb, vs_bit_buffer, 5 * 80, NULL, NULL);
 325     vs_bit_count = 0;
 326     for(mb_index = 0; mb_index < 5; mb_index++) {
 327         /* skip header */
 328         quant = buf_ptr[3] & 0x0f;
 329         buf_ptr += 4;
 330         init_put_bits(&pb, mb_bit_buffer, 80, NULL, NULL);
 331         mb_bit_count = 0;
 332         mb = mb1;
 333         block = block1;
 334         for(j = 0;j < 6; j++) {
 335             /* NOTE: size is not important here */
 336             init_get_bits(&s->gb, buf_ptr, 14);
 337
 338             /* get the dc */
 339             dc = get_bits(&s->gb, 9);
 340             dc = (dc << (32 - 9)) >> (32 - 9);
 341             dct_mode = get_bits1(&s->gb);
 342             mb->dct_mode = dct_mode;
 343             mb->scan_table = s->dv_zigzag[dct_mode];
 344             class1 = get_bits(&s->gb, 2);
 345             mb->shift_offset = (class1 == 3);
 346             mb->shift_table = s->dv_shift[dct_mode]
 347                 [quant + dv_quant_offset[class1]];
 348             dc = dc << 2;
 349             /* convert to unsigned because 128 is not added in the
 350                standard IDCT */
 351             dc += 1024;
 352             block[0] = dc;
 353             last_index = block_sizes[j];
 354             buf_ptr += last_index >> 3;
 355             mb->pos = 0;
 356             mb->partial_bit_count = 0;
 357
 358             dv_decode_ac(s, mb, block, last_index);
 359
 360             /* write the remaining bits  in a new buffer only if the
 361                block is finished */
 362             bits_left = last_index - s->gb.index;
 363             if (mb->eob_reached) {
 364                 mb->partial_bit_count = 0;
 365                 mb_bit_count += bits_left;
 366                 bit_copy(&pb, &s->gb, bits_left);
 367             } else {
 368                 /* should be < 16 bits otherwise a codeword could have
 369                    been parsed */
 370                 mb->partial_bit_count = bits_left;
 371                 mb->partial_bit_buffer = get_bits(&s->gb, bits_left);
 372             }
 373             block += 64;
 374             mb++;
 375         }
 376
 377         flush_put_bits(&pb);
 378
 379         /* pass 2 : we can do it just after */
 380 #ifdef VLC_DEBUG
 381         printf("***pass 2 size=%d\n", mb_bit_count);
 382 #endif
 383         block = block1;
 384         mb = mb1;
 385         init_get_bits(&s->gb, mb_bit_buffer, 80);
 386         for(j = 0;j < 6; j++) {
 387             if (!mb->eob_reached && s->gb.index < mb_bit_count) {
 388                 dv_decode_ac(s, mb, block, mb_bit_count);
 389                 /* if still not finished, no need to parse other blocks */
 390                 if (!mb->eob_reached) {
 391                     /* we could not parse the current AC coefficient,
 392                        so we add the remaining bytes */
 393                     bits_left = mb_bit_count - s->gb.index;
 394                     if (bits_left > 0) {
 395                         mb->partial_bit_count += bits_left;
 396                         mb->partial_bit_buffer =
 397                             (mb->partial_bit_buffer << bits_left) |
 398                             get_bits(&s->gb, bits_left);
 399                     }
 400                     goto next_mb;
 401                 }
 402             }
 403             block += 64;
 404             mb++;
 405         }
 406         /* all blocks are finished, so the extra bytes can be used at
 407            the video segment level */
 408         bits_left = mb_bit_count - s->gb.index;
 409         vs_bit_count += bits_left;
 410         bit_copy(&vs_pb, &s->gb, bits_left);
 411     next_mb:
 412         mb1 += 6;
 413         block1 += 6 * 64;
 414     }
 415
 416     /* we need a pass other the whole video segment */
 417     flush_put_bits(&vs_pb);
 418
 419 #ifdef VLC_DEBUG
 420     printf("***pass 3 size=%d\n", vs_bit_count);
 421 #endif
 422     block = &s->block[0][0];
 423     mb = mb_data;
 424     init_get_bits(&s->gb, vs_bit_buffer, 5 * 80);
 425     for(mb_index = 0; mb_index < 5; mb_index++) {
 426         for(j = 0;j < 6; j++) {
 427             if (!mb->eob_reached) {
 428 #ifdef VLC_DEBUG
 429                 printf("start %d:%d\n", mb_index, j);
 430 #endif
 431                 dv_decode_ac(s, mb, block, vs_bit_count);
 432             }
 433             block += 64;
 434             mb++;
 435         }
 436     }
 437
 438     /* compute idct and place blocks */
 439     block = &s->block[0][0];
 440     mb = mb_data;
 441     for(mb_index = 0; mb_index < 5; mb_index++) {
 442         v = *mb_pos_ptr++;
 443         mb_x = v & 0xff;
 444         mb_y = v >> 8;
 445         y_ptr = s->current_picture[0] + (mb_y * s->linesize[0] * 8) + (mb_x * 8);
 446         if (s->sampling_411)
 447             c_offset = (mb_y * s->linesize[1] * 8) + ((mb_x >> 2) * 8);
 448         else
 449             c_offset = ((mb_y >> 1) * s->linesize[1] * 8) + ((mb_x >> 1) * 8);
 450         for(j = 0;j < 6; j++) {
 451             idct_put = s->idct_put[mb->dct_mode];
 452             if (j < 4) {
 453                 if (s->sampling_411 && mb_x < (704 / 8)) {
 454                     /* NOTE: at end of line, the macroblock is handled as 420 */
 455                     idct_put(y_ptr + (j * 8), s->linesize[0], block);
 456                 } else {
 457                     idct_put(y_ptr + ((j & 1) * 8) + ((j >> 1) * 8 * s->linesize[0]),
 458                              s->linesize[0], block);
 459                 }
 460             } else {
 461                 if (s->sampling_411 && mb_x >= (704 / 8)) {
 462                     uint8_t pixels[64], *c_ptr, *c_ptr1, *ptr;
 463                     int y, linesize;
 464                     /* NOTE: at end of line, the macroblock is handled as 420 */
 465                     idct_put(pixels, 8, block);
 466                     linesize = s->linesize[6 - j];
 467                     c_ptr = s->current_picture[6 - j] + c_offset;
 468                     ptr = pixels;
 469                     for(y = 0;y < 8; y++) {
 470                         /* convert to 411P */
 471                         c_ptr1 = c_ptr + linesize;
 472                         c_ptr1[0] = c_ptr[0] = (ptr[0] + ptr[1]) >> 1;
 473                         c_ptr1[1] = c_ptr[1] = (ptr[2] + ptr[3]) >> 1;
 474                         c_ptr1[2] = c_ptr[2] = (ptr[4] + ptr[5]) >> 1;
 475                         c_ptr1[3] = c_ptr[3] = (ptr[6] + ptr[7]) >> 1;
 476                         c_ptr += linesize * 2;
 477                         ptr += 8;
 478                     }
 479                 } else {
 480                     /* don't ask me why they inverted Cb and Cr ! */
 481                     idct_put(s->current_picture[6 - j] + c_offset,
 482                              s->linesize[6 - j], block);
 483                 }
 484             }
 485             block += 64;
 486             mb++;
 487         }
 488     }
 489 }
 490
 491
 492 /* NOTE: exactly one frame must be given (120000 bytes for NTSC,
 493    144000 bytes for PAL) */
 494 static int dvvideo_decode_frame(AVCodecContext *avctx,
 495                                  void *data, int *data_size,
 496                                  UINT8 *buf, int buf_size)
 497 {
 498     DVVideoDecodeContext *s = avctx->priv_data;
 499     int sct, dsf, apt, ds, nb_dif_segs, vs, width, height, i, packet_size;
 500     unsigned size;
 501     UINT8 *buf_ptr;
 502     const UINT16 *mb_pos_ptr;
 503
 504     /* parse id */
 505     init_get_bits(&s->gb, buf, buf_size);
 506     sct = get_bits(&s->gb, 3);
 507     if (sct != 0)
 508         return -1;
 509     skip_bits(&s->gb, 5);
 510     get_bits(&s->gb, 4); /* dsn (sequence number */
 511     get_bits(&s->gb, 1); /* fsc (channel number) */
 512     skip_bits(&s->gb, 3);
 513     get_bits(&s->gb, 8); /* dbn (diff block number 0-134) */
 514
 515     dsf = get_bits(&s->gb, 1); /* 0 = NTSC 1 = PAL */
 516     if (get_bits(&s->gb, 1) != 0)
 517         return -1;
 518     skip_bits(&s->gb, 11);
 519     apt = get_bits(&s->gb, 3); /* apt */
 520
 521     get_bits(&s->gb, 1); /* tf1 */
 522     skip_bits(&s->gb, 4);
 523     get_bits(&s->gb, 3); /* ap1 */
 524
 525     get_bits(&s->gb, 1); /* tf2 */
 526     skip_bits(&s->gb, 4);
 527     get_bits(&s->gb, 3); /* ap2 */
 528
 529     get_bits(&s->gb, 1); /* tf3 */
 530     skip_bits(&s->gb, 4);
 531     get_bits(&s->gb, 3); /* ap3 */
 532
 533     /* init size */
 534     width = 720;
 535     if (dsf) {
 536         avctx->frame_rate = 25 * FRAME_RATE_BASE;
 537         packet_size = PAL_FRAME_SIZE;
 538         height = 576;
 539         nb_dif_segs = 12;
 540     } else {
 541         avctx->frame_rate = 30 * FRAME_RATE_BASE;
 542         packet_size = NTSC_FRAME_SIZE;
 543         height = 480;
 544         nb_dif_segs = 10;
 545     }
 546     /* NOTE: we only accept several full frames */
 547     if (buf_size < packet_size)
 548         return -1;
 549
 550     /* XXX: is it correct to assume that 420 is always used in PAL
 551        mode ? */
 552     s->sampling_411 = !dsf;
 553     if (s->sampling_411) {
 554         mb_pos_ptr = dv_place_411;
 555         avctx->pix_fmt = PIX_FMT_YUV411P;
 556     } else {
 557         mb_pos_ptr = dv_place_420;
 558         avctx->pix_fmt = PIX_FMT_YUV420P;
 559     }
 560
 561     avctx->width = width;
 562     avctx->height = height;
 563
 564     s->picture.reference= 0;
 565     if(avctx->get_buffer(avctx, &s->picture) < 0) {
 566         fprintf(stderr, "get_buffer() failed\n");
 567         return -1;
 568     }
 569
 570     for(i=0;i<3;i++) {
 571         s->current_picture[i] = s->picture.data[i];
 572         s->linesize[i] = s->picture.linesize[i];
 573         if (!s->current_picture[i])
 574             return -1;
 575     }
 576     s->width = width;
 577     s->height = height;
 578
 579     /* for each DIF segment */
 580     buf_ptr = buf;
 581     for (ds = 0; ds < nb_dif_segs; ds++) {
 582         buf_ptr += 6 * 80; /* skip DIF segment header */
 583
 584         for(vs = 0; vs < 27; vs++) {
 585             if ((vs % 3) == 0) {
 586                 /* skip audio block */
 587                 buf_ptr += 80;
 588             }
 589             dv_decode_video_segment(s, buf_ptr, mb_pos_ptr);
 590             buf_ptr += 5 * 80;
 591             mb_pos_ptr += 5;
 592         }
 593     }
 594
 595     emms_c();
 596
 597     /* return image */
 598     *data_size = sizeof(AVFrame);
 599     *(AVFrame*)data= s->picture;
 600
 601     avctx->release_buffer(avctx, &s->picture);
 602
 603     return packet_size;
 604 }
 605
 606 static int dvvideo_decode_end(AVCodecContext *avctx)
 607 {
 608     DVVideoDecodeContext *s = avctx->priv_data;
 609     int i;
 610
 611     if(avctx->get_buffer == avcodec_default_get_buffer){
 612         for(i=0; i<4; i++){
 613             av_freep(&s->picture.base[i]);
 614             s->picture.data[i]= NULL;
 615         }
 616         av_freep(&s->picture.opaque);
 617     }
 618
 619     return 0;
 620 }
 621
 622 AVCodec dvvideo_decoder = {
 623     "dvvideo",
 624     CODEC_TYPE_VIDEO,
 625     CODEC_ID_DVVIDEO,
 626     sizeof(DVVideoDecodeContext),
 627     dvvideo_decode_init,
 628     NULL,
 629     dvvideo_decode_end,
 630     dvvideo_decode_frame,
 631     CODEC_CAP_DR1,
 632     NULL
 633 };
 634
 635 typedef struct DVAudioDecodeContext {
 636     AVCodecContext *avctx;
 637     GetBitContext gb;
 638
 639 } DVAudioDecodeContext;
 640
 641 static int dvaudio_decode_init(AVCodecContext *avctx)
 642 {
 643     //    DVAudioDecodeContext *s = avctx->priv_data;
 644     return 0;
 645 }
 646
 647 /* NOTE: exactly one frame must be given (120000 bytes for NTSC,
 648    144000 bytes for PAL) */
 649 static int dvaudio_decode_frame(AVCodecContext *avctx,
 650                                  void *data, int *data_size,
 651                                  UINT8 *buf, int buf_size)
 652 {
 653     //    DVAudioDecodeContext *s = avctx->priv_data;
 654     return buf_size;
 655 }
 656
 657 static int dvaudio_decode_end(AVCodecContext *avctx)
 658 {
 659     //    DVAudioDecodeContext *s = avctx->priv_data;
 660     return 0;
 661 }
 662
 663 AVCodec dvaudio_decoder = {
 664     "dvaudio",
 665     CODEC_TYPE_AUDIO,
 666     CODEC_ID_DVAUDIO,
 667     sizeof(DVAudioDecodeContext),
 668     dvaudio_decode_init,
 669     NULL,
 670     dvaudio_decode_end,
 671     dvaudio_decode_frame,
 672     0,
 673     NULL
 674 };