2 * ITU H263 bitstream decoder
3 * Copyright (c) 2000,2001 Fabrice Bellard
5 * Copyright (c) 2001 Juan J. Sierralta P
6 * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
8 * This file is part of FFmpeg.
10 * FFmpeg is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU Lesser General Public
12 * License as published by the Free Software Foundation; either
13 * version 2.1 of the License, or (at your option) any later version.
15 * FFmpeg is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * Lesser General Public License for more details.
20 * You should have received a copy of the GNU Lesser General Public
21 * License along with FFmpeg; if not, write to the Free Software
22 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
30 #define UNCHECKED_BITSTREAM_READER 1
35 #include "libavutil/mathematics.h"
38 #include "mpegvideo.h"
43 #include "mpeg4video.h"
45 // The defines below define the number of bits that are read at once for
46 // reading vlc values. Changing these may improve speed and data cache needs
47 // be aware though that decreasing them may need the number of stages that is
48 // passed to get_vlc* to be increased.
50 #define H263_MBTYPE_B_VLC_BITS 6
51 #define CBPC_B_VLC_BITS 3
53 static const int h263_mb_type_b_map[15]= {
54 MB_TYPE_DIRECT2 | MB_TYPE_L0L1,
55 MB_TYPE_DIRECT2 | MB_TYPE_L0L1 | MB_TYPE_CBP,
56 MB_TYPE_DIRECT2 | MB_TYPE_L0L1 | MB_TYPE_CBP | MB_TYPE_QUANT,
57 MB_TYPE_L0 | MB_TYPE_16x16,
58 MB_TYPE_L0 | MB_TYPE_CBP | MB_TYPE_16x16,
59 MB_TYPE_L0 | MB_TYPE_CBP | MB_TYPE_QUANT | MB_TYPE_16x16,
60 MB_TYPE_L1 | MB_TYPE_16x16,
61 MB_TYPE_L1 | MB_TYPE_CBP | MB_TYPE_16x16,
62 MB_TYPE_L1 | MB_TYPE_CBP | MB_TYPE_QUANT | MB_TYPE_16x16,
63 MB_TYPE_L0L1 | MB_TYPE_16x16,
64 MB_TYPE_L0L1 | MB_TYPE_CBP | MB_TYPE_16x16,
65 MB_TYPE_L0L1 | MB_TYPE_CBP | MB_TYPE_QUANT | MB_TYPE_16x16,
67 MB_TYPE_INTRA4x4 | MB_TYPE_CBP,
68 MB_TYPE_INTRA4x4 | MB_TYPE_CBP | MB_TYPE_QUANT,
71 void ff_h263_show_pict_info(MpegEncContext *s){
72 if(s->avctx->debug&FF_DEBUG_PICT_INFO){
73 av_log(s->avctx, AV_LOG_DEBUG, "qp:%d %c size:%d rnd:%d%s%s%s%s%s%s%s%s%s %d/%d\n",
74 s->qscale, av_get_picture_type_char(s->pict_type),
75 s->gb.size_in_bits, 1-s->no_rounding,
77 s->umvplus ? " UMV" : "",
78 s->h263_long_vectors ? " LONG" : "",
79 s->h263_plus ? " +" : "",
80 s->h263_aic ? " AIC" : "",
81 s->alt_inter_vlc ? " AIV" : "",
82 s->modified_quant ? " MQ" : "",
83 s->loop_filter ? " LOOP" : "",
84 s->h263_slice_structured ? " SS" : "",
85 s->avctx->time_base.den, s->avctx->time_base.num
90 /***********************************************/
93 VLC ff_h263_intra_MCBPC_vlc;
94 VLC ff_h263_inter_MCBPC_vlc;
97 static VLC h263_mbtype_b_vlc;
98 static VLC cbpc_b_vlc;
102 /* XXX: find a better solution to handle static init */
103 void ff_h263_decode_init_vlc(MpegEncContext *s)
110 INIT_VLC_STATIC(&ff_h263_intra_MCBPC_vlc, INTRA_MCBPC_VLC_BITS, 9,
111 ff_h263_intra_MCBPC_bits, 1, 1,
112 ff_h263_intra_MCBPC_code, 1, 1, 72);
113 INIT_VLC_STATIC(&ff_h263_inter_MCBPC_vlc, INTER_MCBPC_VLC_BITS, 28,
114 ff_h263_inter_MCBPC_bits, 1, 1,
115 ff_h263_inter_MCBPC_code, 1, 1, 198);
116 INIT_VLC_STATIC(&ff_h263_cbpy_vlc, CBPY_VLC_BITS, 16,
117 &ff_h263_cbpy_tab[0][1], 2, 1,
118 &ff_h263_cbpy_tab[0][0], 2, 1, 64);
119 INIT_VLC_STATIC(&mv_vlc, MV_VLC_BITS, 33,
120 &ff_mvtab[0][1], 2, 1,
121 &ff_mvtab[0][0], 2, 1, 538);
122 ff_init_rl(&ff_h263_rl_inter, ff_h263_static_rl_table_store[0]);
123 ff_init_rl(&ff_rl_intra_aic, ff_h263_static_rl_table_store[1]);
124 INIT_VLC_RL(ff_h263_rl_inter, 554);
125 INIT_VLC_RL(ff_rl_intra_aic, 554);
126 INIT_VLC_STATIC(&h263_mbtype_b_vlc, H263_MBTYPE_B_VLC_BITS, 15,
127 &ff_h263_mbtype_b_tab[0][1], 2, 1,
128 &ff_h263_mbtype_b_tab[0][0], 2, 1, 80);
129 INIT_VLC_STATIC(&cbpc_b_vlc, CBPC_B_VLC_BITS, 4,
130 &ff_cbpc_b_tab[0][1], 2, 1,
131 &ff_cbpc_b_tab[0][0], 2, 1, 8);
135 int ff_h263_decode_mba(MpegEncContext *s)
140 if(s->mb_num-1 <= ff_mba_max[i]) break;
142 mb_pos= get_bits(&s->gb, ff_mba_length[i]);
143 s->mb_x= mb_pos % s->mb_width;
144 s->mb_y= mb_pos / s->mb_width;
150 * Decode the group of blocks header or slice header.
151 * @return <0 if an error occurred
153 static int h263_decode_gob_header(MpegEncContext *s)
155 unsigned int val, gob_number;
158 /* Check for GOB Start Code */
159 val = show_bits(&s->gb, 16);
163 /* We have a GBSC probably with GSTUFF */
164 skip_bits(&s->gb, 16); /* Drop the zeros */
165 left= get_bits_left(&s->gb);
166 //MN: we must check the bits left or we might end in a infinite loop (or segfault)
167 for(;left>13; left--){
168 if(get_bits1(&s->gb)) break; /* Seek the '1' bit */
173 if(s->h263_slice_structured){
174 if(get_bits1(&s->gb)==0)
177 ff_h263_decode_mba(s);
180 if(get_bits1(&s->gb)==0)
183 s->qscale = get_bits(&s->gb, 5); /* SQUANT */
184 if(get_bits1(&s->gb)==0)
186 skip_bits(&s->gb, 2); /* GFID */
188 gob_number = get_bits(&s->gb, 5); /* GN */
190 s->mb_y= s->gob_index* gob_number;
191 skip_bits(&s->gb, 2); /* GFID */
192 s->qscale = get_bits(&s->gb, 5); /* GQUANT */
195 if(s->mb_y >= s->mb_height)
205 * Find the next resync_marker.
206 * @param p pointer to buffer to scan
207 * @param end pointer to the end of the buffer
208 * @return pointer to the next resync_marker, or end if none was found
210 const uint8_t *ff_h263_find_resync_marker(const uint8_t *av_restrict p, const uint8_t *av_restrict end)
218 if (!p[-1] && p[1]) return p - 1;
219 else if(!p[ 1] && p[2]) return p;
226 * Decode the group of blocks / video packet header.
227 * @return bit position of the resync_marker, or <0 if none was found
229 int ff_h263_resync(MpegEncContext *s){
232 if(s->codec_id==AV_CODEC_ID_MPEG4){
234 align_get_bits(&s->gb);
237 if(show_bits(&s->gb, 16)==0){
238 pos= get_bits_count(&s->gb);
239 if(CONFIG_MPEG4_DECODER && s->codec_id==AV_CODEC_ID_MPEG4)
240 ret= ff_mpeg4_decode_video_packet_header(s);
242 ret= h263_decode_gob_header(s);
246 //OK, it's not where it is supposed to be ...
247 s->gb= s->last_resync_gb;
248 align_get_bits(&s->gb);
249 left= get_bits_left(&s->gb);
251 for(;left>16+1+5+5; left-=8){
252 if(show_bits(&s->gb, 16)==0){
253 GetBitContext bak= s->gb;
255 pos= get_bits_count(&s->gb);
256 if(CONFIG_MPEG4_DECODER && s->codec_id==AV_CODEC_ID_MPEG4)
257 ret= ff_mpeg4_decode_video_packet_header(s);
259 ret= h263_decode_gob_header(s);
265 skip_bits(&s->gb, 8);
271 int ff_h263_decode_motion(MpegEncContext * s, int pred, int f_code)
273 int code, val, sign, shift;
274 code = get_vlc2(&s->gb, mv_vlc.table, MV_VLC_BITS, 2);
281 sign = get_bits1(&s->gb);
285 val = (val - 1) << shift;
286 val |= get_bits(&s->gb, shift);
293 /* modulo decoding */
294 if (!s->h263_long_vectors) {
295 val = sign_extend(val, 5 + f_code);
297 /* horrible h263 long vector mode */
298 if (pred < -31 && val < -63)
300 if (pred > 32 && val > 63)
308 /* Decode RVLC of H.263+ UMV */
309 static int h263p_decode_umotion(MpegEncContext * s, int pred)
313 if (get_bits1(&s->gb)) /* Motion difference = 0 */
316 code = 2 + get_bits1(&s->gb);
318 while (get_bits1(&s->gb))
321 code += get_bits1(&s->gb);
326 code = (sign) ? (pred - code) : (pred + code);
327 av_dlog(s->avctx,"H.263+ UMV Motion = %d\n", code);
333 * read the next MVs for OBMC. yes this is a ugly hack, feel free to send a patch :)
335 static void preview_obmc(MpegEncContext *s){
336 GetBitContext gb= s->gb;
338 int cbpc, i, pred_x, pred_y, mx, my;
340 const int xy= s->mb_x + 1 + s->mb_y * s->mb_stride;
341 const int stride= s->b8_stride*2;
344 s->block_index[i]+= 2;
346 s->block_index[i]+= 1;
349 av_assert2(s->pict_type == AV_PICTURE_TYPE_P);
352 if (get_bits1(&s->gb)) {
354 mot_val = s->current_picture.f.motion_val[0][s->block_index[0]];
355 mot_val[0 ]= mot_val[2 ]=
356 mot_val[0+stride]= mot_val[2+stride]= 0;
357 mot_val[1 ]= mot_val[3 ]=
358 mot_val[1+stride]= mot_val[3+stride]= 0;
360 s->current_picture.f.mb_type[xy] = MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
363 cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
367 s->current_picture.f.mb_type[xy] = MB_TYPE_INTRA;
369 get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
371 if(s->modified_quant){
372 if(get_bits1(&s->gb)) skip_bits(&s->gb, 1);
373 else skip_bits(&s->gb, 5);
375 skip_bits(&s->gb, 2);
378 if ((cbpc & 16) == 0) {
379 s->current_picture.f.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
380 /* 16x16 motion prediction */
381 mot_val= ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
383 mx = h263p_decode_umotion(s, pred_x);
385 mx = ff_h263_decode_motion(s, pred_x, 1);
388 my = h263p_decode_umotion(s, pred_y);
390 my = ff_h263_decode_motion(s, pred_y, 1);
392 mot_val[0 ]= mot_val[2 ]=
393 mot_val[0+stride]= mot_val[2+stride]= mx;
394 mot_val[1 ]= mot_val[3 ]=
395 mot_val[1+stride]= mot_val[3+stride]= my;
397 s->current_picture.f.mb_type[xy] = MB_TYPE_8x8 | MB_TYPE_L0;
399 mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
401 mx = h263p_decode_umotion(s, pred_x);
403 mx = ff_h263_decode_motion(s, pred_x, 1);
406 my = h263p_decode_umotion(s, pred_y);
408 my = ff_h263_decode_motion(s, pred_y, 1);
409 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
410 skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
419 s->block_index[i]-= 2;
421 s->block_index[i]-= 1;
427 static void h263_decode_dquant(MpegEncContext *s){
428 static const int8_t quant_tab[4] = { -1, -2, 1, 2 };
430 if(s->modified_quant){
431 if(get_bits1(&s->gb))
432 s->qscale= ff_modified_quant_tab[get_bits1(&s->gb)][ s->qscale ];
434 s->qscale= get_bits(&s->gb, 5);
436 s->qscale += quant_tab[get_bits(&s->gb, 2)];
437 ff_set_qscale(s, s->qscale);
440 static int h263_decode_block(MpegEncContext * s, DCTELEM * block,
443 int code, level, i, j, last, run;
444 RLTable *rl = &ff_h263_rl_inter;
445 const uint8_t *scan_table;
446 GetBitContext gb= s->gb;
448 scan_table = s->intra_scantable.permutated;
449 if (s->h263_aic && s->mb_intra) {
450 rl = &ff_rl_intra_aic;
454 scan_table = s->intra_v_scantable.permutated; /* left */
456 scan_table = s->intra_h_scantable.permutated; /* top */
458 } else if (s->mb_intra) {
460 if(s->codec_id == AV_CODEC_ID_RV10){
461 #if CONFIG_RV10_DECODER
462 if (s->rv10_version == 3 && s->pict_type == AV_PICTURE_TYPE_I) {
464 component = (n <= 3 ? 0 : n - 4 + 1);
465 level = s->last_dc[component];
466 if (s->rv10_first_dc_coded[component]) {
467 diff = ff_rv_decode_dc(s, n);
471 level = level & 0xff; /* handle wrap round */
472 s->last_dc[component] = level;
474 s->rv10_first_dc_coded[component] = 1;
477 level = get_bits(&s->gb, 8);
483 level = get_bits(&s->gb, 8);
484 if((level&0x7F) == 0){
485 av_log(s->avctx, AV_LOG_ERROR, "illegal dc %d at %d %d\n", level, s->mb_x, s->mb_y);
486 if(s->err_recognition & (AV_EF_BITSTREAM|AV_EF_COMPLIANT))
498 if (s->mb_intra && s->h263_aic)
500 s->block_last_index[n] = i - 1;
505 code = get_vlc2(&s->gb, rl->vlc.table, TEX_VLC_BITS, 2);
507 av_log(s->avctx, AV_LOG_ERROR, "illegal ac vlc code at %dx%d\n", s->mb_x, s->mb_y);
512 if (CONFIG_FLV_DECODER && s->h263_flv > 1) {
513 ff_flv2_decode_ac_esc(&s->gb, &level, &run, &last);
515 last = get_bits1(&s->gb);
516 run = get_bits(&s->gb, 6);
517 level = (int8_t)get_bits(&s->gb, 8);
519 if (s->codec_id == AV_CODEC_ID_RV10) {
520 /* XXX: should patch encoder too */
521 level = get_sbits(&s->gb, 12);
523 level = get_bits(&s->gb, 5);
524 level |= get_sbits(&s->gb, 6)<<5;
529 run = rl->table_run[code];
530 level = rl->table_level[code];
531 last = code >= rl->last;
532 if (get_bits1(&s->gb))
537 if(s->alt_inter_vlc && rl == &ff_h263_rl_inter && !s->mb_intra){
538 //Looks like a hack but no, it's the way it is supposed to work ...
539 rl = &ff_rl_intra_aic;
542 s->dsp.clear_block(block);
545 av_log(s->avctx, AV_LOG_ERROR, "run overflow at %dx%d i:%d\n", s->mb_x, s->mb_y, s->mb_intra);
555 if (s->mb_intra && s->h263_aic) {
556 ff_h263_pred_acdc(s, block, n);
559 s->block_last_index[n] = i;
563 static int h263_skip_b_part(MpegEncContext *s, int cbp)
565 LOCAL_ALIGNED_16(DCTELEM, dblock, [64]);
568 /* we have to set s->mb_intra to zero to decode B-part of PB-frame correctly
569 * but real value should be restored in order to be used later (in OBMC condition)
573 for (i = 0; i < 6; i++) {
574 if (h263_decode_block(s, dblock, i, cbp&32) < 0)
582 static int h263_get_modb(GetBitContext *gb, int pb_frame, int *cbpb)
586 if (pb_frame < 3) { // h.263 Annex G and i263 PB-frame
588 if (pb_frame == 2 && c)
590 } else { // h.263 Annex M improved PB-frame
591 mv = get_unary(gb, 0, 4) + 1;
596 *cbpb = get_bits(gb, 6);
600 int ff_h263_decode_mb(MpegEncContext *s,
601 DCTELEM block[6][64])
603 int cbpc, cbpy, i, cbp, pred_x, pred_y, mx, my, dquant;
605 const int xy= s->mb_x + s->mb_y * s->mb_stride;
606 int cbpb = 0, pb_mv_count = 0;
608 av_assert2(!s->h263_pred);
610 if (s->pict_type == AV_PICTURE_TYPE_P) {
612 if (get_bits1(&s->gb)) {
616 s->block_last_index[i] = -1;
617 s->mv_dir = MV_DIR_FORWARD;
618 s->mv_type = MV_TYPE_16X16;
619 s->current_picture.f.mb_type[xy] = MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
622 s->mb_skipped = !(s->obmc | s->loop_filter);
625 cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
627 av_log(s->avctx, AV_LOG_ERROR, "cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
632 s->dsp.clear_blocks(s->block[0]);
635 s->mb_intra = ((cbpc & 4) != 0);
636 if (s->mb_intra) goto intra;
638 if(s->pb_frame && get_bits1(&s->gb))
639 pb_mv_count = h263_get_modb(&s->gb, s->pb_frame, &cbpb);
640 cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
642 if(s->alt_inter_vlc==0 || (cbpc & 3)!=3)
645 cbp = (cbpc & 3) | (cbpy << 2);
647 h263_decode_dquant(s);
650 s->mv_dir = MV_DIR_FORWARD;
651 if ((cbpc & 16) == 0) {
652 s->current_picture.f.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
653 /* 16x16 motion prediction */
654 s->mv_type = MV_TYPE_16X16;
655 ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
657 mx = h263p_decode_umotion(s, pred_x);
659 mx = ff_h263_decode_motion(s, pred_x, 1);
665 my = h263p_decode_umotion(s, pred_y);
667 my = ff_h263_decode_motion(s, pred_y, 1);
674 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
675 skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
677 s->current_picture.f.mb_type[xy] = MB_TYPE_8x8 | MB_TYPE_L0;
678 s->mv_type = MV_TYPE_8X8;
680 mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
682 mx = h263p_decode_umotion(s, pred_x);
684 mx = ff_h263_decode_motion(s, pred_x, 1);
689 my = h263p_decode_umotion(s, pred_y);
691 my = ff_h263_decode_motion(s, pred_y, 1);
696 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
697 skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
702 } else if(s->pict_type==AV_PICTURE_TYPE_B) {
704 const int stride= s->b8_stride;
705 int16_t *mot_val0 = s->current_picture.f.motion_val[0][2 * (s->mb_x + s->mb_y * stride)];
706 int16_t *mot_val1 = s->current_picture.f.motion_val[1][2 * (s->mb_x + s->mb_y * stride)];
707 // const int mv_xy= s->mb_x + 1 + s->mb_y * s->mb_stride;
710 mot_val0[0 ]= mot_val0[2 ]= mot_val0[0+2*stride]= mot_val0[2+2*stride]=
711 mot_val0[1 ]= mot_val0[3 ]= mot_val0[1+2*stride]= mot_val0[3+2*stride]=
712 mot_val1[0 ]= mot_val1[2 ]= mot_val1[0+2*stride]= mot_val1[2+2*stride]=
713 mot_val1[1 ]= mot_val1[3 ]= mot_val1[1+2*stride]= mot_val1[3+2*stride]= 0;
716 mb_type= get_vlc2(&s->gb, h263_mbtype_b_vlc.table, H263_MBTYPE_B_VLC_BITS, 2);
718 av_log(s->avctx, AV_LOG_ERROR, "b mb_type damaged at %d %d\n", s->mb_x, s->mb_y);
722 mb_type= h263_mb_type_b_map[ mb_type ];
725 s->mb_intra = IS_INTRA(mb_type);
726 if(HAS_CBP(mb_type)){
727 s->dsp.clear_blocks(s->block[0]);
728 cbpc = get_vlc2(&s->gb, cbpc_b_vlc.table, CBPC_B_VLC_BITS, 1);
730 dquant = IS_QUANT(mb_type);
734 cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
737 av_log(s->avctx, AV_LOG_ERROR, "b cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
741 if(s->alt_inter_vlc==0 || (cbpc & 3)!=3)
744 cbp = (cbpc & 3) | (cbpy << 2);
748 av_assert2(!s->mb_intra);
750 if(IS_QUANT(mb_type)){
751 h263_decode_dquant(s);
754 if(IS_DIRECT(mb_type)){
755 s->mv_dir = MV_DIR_FORWARD | MV_DIR_BACKWARD | MV_DIRECT;
756 mb_type |= ff_mpeg4_set_direct_mv(s, 0, 0);
759 s->mv_type= MV_TYPE_16X16;
762 if(USES_LIST(mb_type, 0)){
763 int16_t *mot_val= ff_h263_pred_motion(s, 0, 0, &mx, &my);
764 s->mv_dir = MV_DIR_FORWARD;
766 mx = ff_h263_decode_motion(s, mx, 1);
767 my = ff_h263_decode_motion(s, my, 1);
771 mot_val[0 ]= mot_val[2 ]= mot_val[0+2*stride]= mot_val[2+2*stride]= mx;
772 mot_val[1 ]= mot_val[3 ]= mot_val[1+2*stride]= mot_val[3+2*stride]= my;
775 if(USES_LIST(mb_type, 1)){
776 int16_t *mot_val= ff_h263_pred_motion(s, 0, 1, &mx, &my);
777 s->mv_dir |= MV_DIR_BACKWARD;
779 mx = ff_h263_decode_motion(s, mx, 1);
780 my = ff_h263_decode_motion(s, my, 1);
784 mot_val[0 ]= mot_val[2 ]= mot_val[0+2*stride]= mot_val[2+2*stride]= mx;
785 mot_val[1 ]= mot_val[3 ]= mot_val[1+2*stride]= mot_val[3+2*stride]= my;
789 s->current_picture.f.mb_type[xy] = mb_type;
790 } else { /* I-Frame */
792 cbpc = get_vlc2(&s->gb, ff_h263_intra_MCBPC_vlc.table, INTRA_MCBPC_VLC_BITS, 2);
794 av_log(s->avctx, AV_LOG_ERROR, "I cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
799 s->dsp.clear_blocks(s->block[0]);
804 s->current_picture.f.mb_type[xy] = MB_TYPE_INTRA;
806 s->ac_pred = get_bits1(&s->gb);
808 s->current_picture.f.mb_type[xy] = MB_TYPE_INTRA | MB_TYPE_ACPRED;
810 s->h263_aic_dir = get_bits1(&s->gb);
815 if(s->pb_frame && get_bits1(&s->gb))
816 pb_mv_count = h263_get_modb(&s->gb, s->pb_frame, &cbpb);
817 cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
819 av_log(s->avctx, AV_LOG_ERROR, "I cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
822 cbp = (cbpc & 3) | (cbpy << 2);
824 h263_decode_dquant(s);
827 pb_mv_count += !!s->pb_frame;
830 while(pb_mv_count--){
831 ff_h263_decode_motion(s, 0, 1);
832 ff_h263_decode_motion(s, 0, 1);
835 /* decode each block */
836 for (i = 0; i < 6; i++) {
837 if (h263_decode_block(s, block[i], i, cbp&32) < 0)
842 if(s->pb_frame && h263_skip_b_part(s, cbpb) < 0)
844 if(s->obmc && !s->mb_intra){
845 if(s->pict_type == AV_PICTURE_TYPE_P && s->mb_x+1<s->mb_width && s->mb_num_left != 1)
850 /* per-MB end of slice check */
852 int v= show_bits(&s->gb, 16);
854 if (get_bits_left(&s->gb) < 16) {
855 v >>= 16 - get_bits_left(&s->gb);
865 /* most is hardcoded. should extend to handle all h263 streams */
866 int ff_h263_decode_picture_header(MpegEncContext *s)
868 int format, width, height, i;
871 align_get_bits(&s->gb);
873 startcode= get_bits(&s->gb, 22-8);
875 for(i= get_bits_left(&s->gb); i>24; i-=8) {
876 startcode = ((startcode << 8) | get_bits(&s->gb, 8)) & 0x003FFFFF;
878 if(startcode == 0x20)
882 if (startcode != 0x20) {
883 av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
886 /* temporal reference */
887 i = get_bits(&s->gb, 8); /* picture timestamp */
888 if( (s->picture_number&~0xFF)+i < s->picture_number)
890 s->current_picture_ptr->f.pts =
891 s->picture_number= (s->picture_number&~0xFF) + i;
893 /* PTYPE starts here */
894 if (get_bits1(&s->gb) != 1) {
896 av_log(s->avctx, AV_LOG_ERROR, "Bad marker\n");
899 if (get_bits1(&s->gb) != 0) {
900 av_log(s->avctx, AV_LOG_ERROR, "Bad H263 id\n");
901 return -1; /* h263 id */
903 skip_bits1(&s->gb); /* split screen off */
904 skip_bits1(&s->gb); /* camera off */
905 skip_bits1(&s->gb); /* freeze picture release off */
907 format = get_bits(&s->gb, 3);
912 7 extended PTYPE (PLUSPTYPE)
915 if (format != 7 && format != 6) {
918 width = ff_h263_format[format][0];
919 height = ff_h263_format[format][1];
923 s->pict_type = AV_PICTURE_TYPE_I + get_bits1(&s->gb);
925 s->h263_long_vectors = get_bits1(&s->gb);
927 if (get_bits1(&s->gb) != 0) {
928 av_log(s->avctx, AV_LOG_ERROR, "H263 SAC not supported\n");
929 return -1; /* SAC: off */
931 s->obmc= get_bits1(&s->gb); /* Advanced prediction mode */
932 s->unrestricted_mv = s->h263_long_vectors || s->obmc;
934 s->pb_frame = get_bits1(&s->gb);
935 s->chroma_qscale= s->qscale = get_bits(&s->gb, 5);
936 skip_bits1(&s->gb); /* Continuous Presence Multipoint mode: off */
940 s->avctx->sample_aspect_ratio= (AVRational){12,11};
941 s->avctx->time_base= (AVRational){1001, 30000};
947 ufep = get_bits(&s->gb, 3); /* Update Full Extended PTYPE */
949 /* ufep other than 0 and 1 are reserved */
952 format = get_bits(&s->gb, 3);
953 av_dlog(s->avctx, "ufep=1, format: %d\n", format);
954 s->custom_pcf= get_bits1(&s->gb);
955 s->umvplus = get_bits1(&s->gb); /* Unrestricted Motion Vector */
956 if (get_bits1(&s->gb) != 0) {
957 av_log(s->avctx, AV_LOG_ERROR, "Syntax-based Arithmetic Coding (SAC) not supported\n");
959 s->obmc= get_bits1(&s->gb); /* Advanced prediction mode */
960 s->h263_aic = get_bits1(&s->gb); /* Advanced Intra Coding (AIC) */
961 s->loop_filter= get_bits1(&s->gb);
962 s->unrestricted_mv = s->umvplus || s->obmc || s->loop_filter;
966 s->h263_slice_structured= get_bits1(&s->gb);
967 if (get_bits1(&s->gb) != 0) {
968 av_log(s->avctx, AV_LOG_ERROR, "Reference Picture Selection not supported\n");
970 if (get_bits1(&s->gb) != 0) {
971 av_log(s->avctx, AV_LOG_ERROR, "Independent Segment Decoding not supported\n");
973 s->alt_inter_vlc= get_bits1(&s->gb);
974 s->modified_quant= get_bits1(&s->gb);
975 if(s->modified_quant)
976 s->chroma_qscale_table= ff_h263_chroma_qscale_table;
978 skip_bits(&s->gb, 1); /* Prevent start code emulation */
980 skip_bits(&s->gb, 3); /* Reserved */
981 } else if (ufep != 0) {
982 av_log(s->avctx, AV_LOG_ERROR, "Bad UFEP type (%d)\n", ufep);
987 s->pict_type = get_bits(&s->gb, 3);
988 switch(s->pict_type){
989 case 0: s->pict_type= AV_PICTURE_TYPE_I;break;
990 case 1: s->pict_type= AV_PICTURE_TYPE_P;break;
991 case 2: s->pict_type= AV_PICTURE_TYPE_P;s->pb_frame = 3;break;
992 case 3: s->pict_type= AV_PICTURE_TYPE_B;break;
993 case 7: s->pict_type= AV_PICTURE_TYPE_I;break; //ZYGO
997 skip_bits(&s->gb, 2);
998 s->no_rounding = get_bits1(&s->gb);
999 skip_bits(&s->gb, 4);
1001 /* Get the picture dimensions */
1004 /* Custom Picture Format (CPFMT) */
1005 s->aspect_ratio_info = get_bits(&s->gb, 4);
1006 av_dlog(s->avctx, "aspect: %d\n", s->aspect_ratio_info);
1011 3 - 10:11 (525-type 4:3)
1012 4 - 16:11 (CIF 16:9)
1013 5 - 40:33 (525-type 16:9)
1016 width = (get_bits(&s->gb, 9) + 1) * 4;
1018 height = get_bits(&s->gb, 9) * 4;
1019 av_dlog(s->avctx, "\nH.263+ Custom picture: %dx%d\n",width,height);
1020 if (s->aspect_ratio_info == FF_ASPECT_EXTENDED) {
1021 /* aspected dimensions */
1022 s->avctx->sample_aspect_ratio.num= get_bits(&s->gb, 8);
1023 s->avctx->sample_aspect_ratio.den= get_bits(&s->gb, 8);
1025 s->avctx->sample_aspect_ratio= ff_h263_pixel_aspect[s->aspect_ratio_info];
1028 width = ff_h263_format[format][0];
1029 height = ff_h263_format[format][1];
1030 s->avctx->sample_aspect_ratio= (AVRational){12,11};
1032 if ((width == 0) || (height == 0))
1039 s->avctx->time_base.den= 1800000;
1040 s->avctx->time_base.num= 1000 + get_bits1(&s->gb);
1041 s->avctx->time_base.num*= get_bits(&s->gb, 7);
1042 if(s->avctx->time_base.num == 0){
1043 av_log(s, AV_LOG_ERROR, "zero framerate\n");
1046 gcd= av_gcd(s->avctx->time_base.den, s->avctx->time_base.num);
1047 s->avctx->time_base.den /= gcd;
1048 s->avctx->time_base.num /= gcd;
1050 s->avctx->time_base= (AVRational){1001, 30000};
1055 skip_bits(&s->gb, 2); //extended Temporal reference
1060 if(get_bits1(&s->gb)==0) /* Unlimited Unrestricted Motion Vectors Indicator (UUI) */
1063 if(s->h263_slice_structured){
1064 if (get_bits1(&s->gb) != 0) {
1065 av_log(s->avctx, AV_LOG_ERROR, "rectangular slices not supported\n");
1067 if (get_bits1(&s->gb) != 0) {
1068 av_log(s->avctx, AV_LOG_ERROR, "unordered slices not supported\n");
1073 s->qscale = get_bits(&s->gb, 5);
1076 s->mb_width = (s->width + 15) / 16;
1077 s->mb_height = (s->height + 15) / 16;
1078 s->mb_num = s->mb_width * s->mb_height;
1081 skip_bits(&s->gb, 3); /* Temporal reference for B-pictures */
1083 skip_bits(&s->gb, 2); //extended Temporal reference
1084 skip_bits(&s->gb, 2); /* Quantization information for B-pictures */
1087 if (s->pict_type!=AV_PICTURE_TYPE_B) {
1088 s->time = s->picture_number;
1089 s->pp_time = s->time - s->last_non_b_time;
1090 s->last_non_b_time = s->time;
1092 s->time = s->picture_number;
1093 s->pb_time = s->pp_time - (s->last_non_b_time - s->time);
1094 if (s->pp_time <=s->pb_time ||
1095 s->pp_time <= s->pp_time - s->pb_time ||
1100 ff_mpeg4_init_direct_mv(s);
1104 while (get_bits1(&s->gb) != 0) {
1105 skip_bits(&s->gb, 8);
1108 if(s->h263_slice_structured){
1109 if (get_bits1(&s->gb) != 1) {
1110 av_log(s->avctx, AV_LOG_ERROR, "SEPB1 marker missing\n");
1114 ff_h263_decode_mba(s);
1116 if (get_bits1(&s->gb) != 1) {
1117 av_log(s->avctx, AV_LOG_ERROR, "SEPB2 marker missing\n");
1124 s->y_dc_scale_table=
1125 s->c_dc_scale_table= ff_aic_dc_scale_table;
1127 s->y_dc_scale_table=
1128 s->c_dc_scale_table= ff_mpeg1_dc_scale_table;
1131 ff_h263_show_pict_info(s);
1132 if (s->pict_type == AV_PICTURE_TYPE_I && s->codec_tag == AV_RL32("ZYGO") && get_bits_left(&s->gb) >= 85 + 13*3*16 + 50){
1134 for(i=0; i<85; i++) av_log(s->avctx, AV_LOG_DEBUG, "%d", get_bits1(&s->gb));
1135 av_log(s->avctx, AV_LOG_DEBUG, "\n");
1136 for(i=0; i<13; i++){
1138 int v= get_bits(&s->gb, 8);
1139 v |= get_sbits(&s->gb, 8)<<8;
1140 av_log(s->avctx, AV_LOG_DEBUG, " %5d", v);
1142 av_log(s->avctx, AV_LOG_DEBUG, "\n");
1144 for(i=0; i<50; i++) av_log(s->avctx, AV_LOG_DEBUG, "%d", get_bits1(&s->gb));