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 Libav.
10 * Libav 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 * Libav 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 Libav; if not, write to the Free Software
22 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
32 #include "libavutil/attributes.h"
33 #include "libavutil/internal.h"
34 #include "libavutil/mathematics.h"
36 #include "mpegvideo.h"
41 #include "mpeg4video.h"
43 // The defines below define the number of bits that are read at once for
44 // reading vlc values. Changing these may improve speed and data cache needs
45 // be aware though that decreasing them may need the number of stages that is
46 // passed to get_vlc* to be increased.
48 #define H263_MBTYPE_B_VLC_BITS 6
49 #define CBPC_B_VLC_BITS 3
51 static const int h263_mb_type_b_map[15]= {
52 MB_TYPE_DIRECT2 | MB_TYPE_L0L1,
53 MB_TYPE_DIRECT2 | MB_TYPE_L0L1 | MB_TYPE_CBP,
54 MB_TYPE_DIRECT2 | MB_TYPE_L0L1 | MB_TYPE_CBP | MB_TYPE_QUANT,
55 MB_TYPE_L0 | MB_TYPE_16x16,
56 MB_TYPE_L0 | MB_TYPE_CBP | MB_TYPE_16x16,
57 MB_TYPE_L0 | MB_TYPE_CBP | MB_TYPE_QUANT | MB_TYPE_16x16,
58 MB_TYPE_L1 | MB_TYPE_16x16,
59 MB_TYPE_L1 | MB_TYPE_CBP | MB_TYPE_16x16,
60 MB_TYPE_L1 | MB_TYPE_CBP | MB_TYPE_QUANT | MB_TYPE_16x16,
61 MB_TYPE_L0L1 | MB_TYPE_16x16,
62 MB_TYPE_L0L1 | MB_TYPE_CBP | MB_TYPE_16x16,
63 MB_TYPE_L0L1 | MB_TYPE_CBP | MB_TYPE_QUANT | MB_TYPE_16x16,
65 MB_TYPE_INTRA4x4 | MB_TYPE_CBP,
66 MB_TYPE_INTRA4x4 | MB_TYPE_CBP | MB_TYPE_QUANT,
69 void ff_h263_show_pict_info(MpegEncContext *s){
70 if(s->avctx->debug&FF_DEBUG_PICT_INFO){
71 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",
72 s->qscale, av_get_picture_type_char(s->pict_type),
73 s->gb.size_in_bits, 1-s->no_rounding,
75 s->umvplus ? " UMV" : "",
76 s->h263_long_vectors ? " LONG" : "",
77 s->h263_plus ? " +" : "",
78 s->h263_aic ? " AIC" : "",
79 s->alt_inter_vlc ? " AIV" : "",
80 s->modified_quant ? " MQ" : "",
81 s->loop_filter ? " LOOP" : "",
82 s->h263_slice_structured ? " SS" : "",
83 s->avctx->time_base.den, s->avctx->time_base.num
88 /***********************************************/
91 VLC ff_h263_intra_MCBPC_vlc;
92 VLC ff_h263_inter_MCBPC_vlc;
95 static VLC h263_mbtype_b_vlc;
96 static VLC cbpc_b_vlc;
100 /* XXX: find a better solution to handle static init */
101 av_cold void ff_h263_decode_init_vlc(void)
108 INIT_VLC_STATIC(&ff_h263_intra_MCBPC_vlc, INTRA_MCBPC_VLC_BITS, 9,
109 ff_h263_intra_MCBPC_bits, 1, 1,
110 ff_h263_intra_MCBPC_code, 1, 1, 72);
111 INIT_VLC_STATIC(&ff_h263_inter_MCBPC_vlc, INTER_MCBPC_VLC_BITS, 28,
112 ff_h263_inter_MCBPC_bits, 1, 1,
113 ff_h263_inter_MCBPC_code, 1, 1, 198);
114 INIT_VLC_STATIC(&ff_h263_cbpy_vlc, CBPY_VLC_BITS, 16,
115 &ff_h263_cbpy_tab[0][1], 2, 1,
116 &ff_h263_cbpy_tab[0][0], 2, 1, 64);
117 INIT_VLC_STATIC(&mv_vlc, MV_VLC_BITS, 33,
118 &ff_mvtab[0][1], 2, 1,
119 &ff_mvtab[0][0], 2, 1, 538);
120 ff_init_rl(&ff_h263_rl_inter, ff_h263_static_rl_table_store[0]);
121 ff_init_rl(&ff_rl_intra_aic, ff_h263_static_rl_table_store[1]);
122 INIT_VLC_RL(ff_h263_rl_inter, 554);
123 INIT_VLC_RL(ff_rl_intra_aic, 554);
124 INIT_VLC_STATIC(&h263_mbtype_b_vlc, H263_MBTYPE_B_VLC_BITS, 15,
125 &ff_h263_mbtype_b_tab[0][1], 2, 1,
126 &ff_h263_mbtype_b_tab[0][0], 2, 1, 80);
127 INIT_VLC_STATIC(&cbpc_b_vlc, CBPC_B_VLC_BITS, 4,
128 &ff_cbpc_b_tab[0][1], 2, 1,
129 &ff_cbpc_b_tab[0][0], 2, 1, 8);
133 int ff_h263_decode_mba(MpegEncContext *s)
138 if(s->mb_num-1 <= ff_mba_max[i]) break;
140 mb_pos= get_bits(&s->gb, ff_mba_length[i]);
141 s->mb_x= mb_pos % s->mb_width;
142 s->mb_y= mb_pos / s->mb_width;
148 * Decode the group of blocks header or slice header.
149 * @return <0 if an error occurred
151 static int h263_decode_gob_header(MpegEncContext *s)
153 unsigned int val, gob_number;
156 /* Check for GOB Start Code */
157 val = show_bits(&s->gb, 16);
161 /* We have a GBSC probably with GSTUFF */
162 skip_bits(&s->gb, 16); /* Drop the zeros */
163 left= get_bits_left(&s->gb);
164 //MN: we must check the bits left or we might end in a infinite loop (or segfault)
165 for(;left>13; left--){
166 if(get_bits1(&s->gb)) break; /* Seek the '1' bit */
171 if(s->h263_slice_structured){
172 if(get_bits1(&s->gb)==0)
175 ff_h263_decode_mba(s);
178 if(get_bits1(&s->gb)==0)
181 s->qscale = get_bits(&s->gb, 5); /* SQUANT */
182 if(get_bits1(&s->gb)==0)
184 skip_bits(&s->gb, 2); /* GFID */
186 gob_number = get_bits(&s->gb, 5); /* GN */
188 s->mb_y= s->gob_index* gob_number;
189 skip_bits(&s->gb, 2); /* GFID */
190 s->qscale = get_bits(&s->gb, 5); /* GQUANT */
193 if(s->mb_y >= s->mb_height)
203 * Find the next resync_marker.
204 * @param p pointer to buffer to scan
205 * @param end pointer to the end of the buffer
206 * @return pointer to the next resync_marker, or end if none was found
208 const uint8_t *ff_h263_find_resync_marker(const uint8_t *restrict p, const uint8_t * restrict end)
216 if (!p[-1] && p[1]) return p - 1;
217 else if(!p[ 1] && p[2]) return p;
224 * Decode the group of blocks / video packet header.
225 * @return bit position of the resync_marker, or <0 if none was found
227 int ff_h263_resync(MpegEncContext *s){
230 if(s->codec_id==AV_CODEC_ID_MPEG4){
232 align_get_bits(&s->gb);
235 if(show_bits(&s->gb, 16)==0){
236 pos= get_bits_count(&s->gb);
237 if(CONFIG_MPEG4_DECODER && s->codec_id==AV_CODEC_ID_MPEG4)
238 ret= ff_mpeg4_decode_video_packet_header(s);
240 ret= h263_decode_gob_header(s);
244 //OK, it's not where it is supposed to be ...
245 s->gb= s->last_resync_gb;
246 align_get_bits(&s->gb);
247 left= get_bits_left(&s->gb);
249 for(;left>16+1+5+5; left-=8){
250 if(show_bits(&s->gb, 16)==0){
251 GetBitContext bak= s->gb;
253 pos= get_bits_count(&s->gb);
254 if(CONFIG_MPEG4_DECODER && s->codec_id==AV_CODEC_ID_MPEG4)
255 ret= ff_mpeg4_decode_video_packet_header(s);
257 ret= h263_decode_gob_header(s);
263 skip_bits(&s->gb, 8);
269 int ff_h263_decode_motion(MpegEncContext * s, int pred, int f_code)
271 int code, val, sign, shift;
272 code = get_vlc2(&s->gb, mv_vlc.table, MV_VLC_BITS, 2);
279 sign = get_bits1(&s->gb);
283 val = (val - 1) << shift;
284 val |= get_bits(&s->gb, shift);
291 /* modulo decoding */
292 if (!s->h263_long_vectors) {
293 val = sign_extend(val, 5 + f_code);
295 /* horrible h263 long vector mode */
296 if (pred < -31 && val < -63)
298 if (pred > 32 && val > 63)
306 /* Decode RVLC of H.263+ UMV */
307 static int h263p_decode_umotion(MpegEncContext * s, int pred)
311 if (get_bits1(&s->gb)) /* Motion difference = 0 */
314 code = 2 + get_bits1(&s->gb);
316 while (get_bits1(&s->gb))
319 code += get_bits1(&s->gb);
324 code = (sign) ? (pred - code) : (pred + code);
325 av_dlog(s->avctx,"H.263+ UMV Motion = %d\n", code);
331 * read the next MVs for OBMC. yes this is a ugly hack, feel free to send a patch :)
333 static void preview_obmc(MpegEncContext *s){
334 GetBitContext gb= s->gb;
336 int cbpc, i, pred_x, pred_y, mx, my;
338 const int xy= s->mb_x + 1 + s->mb_y * s->mb_stride;
339 const int stride= s->b8_stride*2;
342 s->block_index[i]+= 2;
344 s->block_index[i]+= 1;
347 assert(s->pict_type == AV_PICTURE_TYPE_P);
350 if (get_bits1(&s->gb)) {
352 mot_val = s->current_picture.motion_val[0][s->block_index[0]];
353 mot_val[0 ]= mot_val[2 ]=
354 mot_val[0+stride]= mot_val[2+stride]= 0;
355 mot_val[1 ]= mot_val[3 ]=
356 mot_val[1+stride]= mot_val[3+stride]= 0;
358 s->current_picture.mb_type[xy] = MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
361 cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
365 s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
367 get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
369 if(s->modified_quant){
370 if(get_bits1(&s->gb)) skip_bits(&s->gb, 1);
371 else skip_bits(&s->gb, 5);
373 skip_bits(&s->gb, 2);
376 if ((cbpc & 16) == 0) {
377 s->current_picture.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
378 /* 16x16 motion prediction */
379 mot_val= ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
381 mx = h263p_decode_umotion(s, pred_x);
383 mx = ff_h263_decode_motion(s, pred_x, 1);
386 my = h263p_decode_umotion(s, pred_y);
388 my = ff_h263_decode_motion(s, pred_y, 1);
390 mot_val[0 ]= mot_val[2 ]=
391 mot_val[0+stride]= mot_val[2+stride]= mx;
392 mot_val[1 ]= mot_val[3 ]=
393 mot_val[1+stride]= mot_val[3+stride]= my;
395 s->current_picture.mb_type[xy] = MB_TYPE_8x8 | MB_TYPE_L0;
397 mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
399 mx = h263p_decode_umotion(s, pred_x);
401 mx = ff_h263_decode_motion(s, pred_x, 1);
404 my = h263p_decode_umotion(s, pred_y);
406 my = ff_h263_decode_motion(s, pred_y, 1);
407 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
408 skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
417 s->block_index[i]-= 2;
419 s->block_index[i]-= 1;
425 static void h263_decode_dquant(MpegEncContext *s){
426 static const int8_t quant_tab[4] = { -1, -2, 1, 2 };
428 if(s->modified_quant){
429 if(get_bits1(&s->gb))
430 s->qscale= ff_modified_quant_tab[get_bits1(&s->gb)][ s->qscale ];
432 s->qscale= get_bits(&s->gb, 5);
434 s->qscale += quant_tab[get_bits(&s->gb, 2)];
435 ff_set_qscale(s, s->qscale);
438 static int h263_decode_block(MpegEncContext * s, int16_t * block,
441 int code, level, i, j, last, run;
442 RLTable *rl = &ff_h263_rl_inter;
443 const uint8_t *scan_table;
444 GetBitContext gb= s->gb;
446 scan_table = s->intra_scantable.permutated;
447 if (s->h263_aic && s->mb_intra) {
448 rl = &ff_rl_intra_aic;
452 scan_table = s->intra_v_scantable.permutated; /* left */
454 scan_table = s->intra_h_scantable.permutated; /* top */
456 } else if (s->mb_intra) {
458 if(s->codec_id == AV_CODEC_ID_RV10){
459 #if CONFIG_RV10_DECODER
460 if (s->rv10_version == 3 && s->pict_type == AV_PICTURE_TYPE_I) {
462 component = (n <= 3 ? 0 : n - 4 + 1);
463 level = s->last_dc[component];
464 if (s->rv10_first_dc_coded[component]) {
465 diff = ff_rv_decode_dc(s, n);
469 level = level & 0xff; /* handle wrap round */
470 s->last_dc[component] = level;
472 s->rv10_first_dc_coded[component] = 1;
475 level = get_bits(&s->gb, 8);
481 level = get_bits(&s->gb, 8);
482 if((level&0x7F) == 0){
483 av_log(s->avctx, AV_LOG_ERROR, "illegal dc %d at %d %d\n", level, s->mb_x, s->mb_y);
484 if(s->err_recognition & AV_EF_BITSTREAM)
496 if (s->mb_intra && s->h263_aic)
498 s->block_last_index[n] = i - 1;
503 code = get_vlc2(&s->gb, rl->vlc.table, TEX_VLC_BITS, 2);
505 av_log(s->avctx, AV_LOG_ERROR, "illegal ac vlc code at %dx%d\n", s->mb_x, s->mb_y);
510 if (CONFIG_FLV_DECODER && s->h263_flv > 1) {
511 ff_flv2_decode_ac_esc(&s->gb, &level, &run, &last);
513 last = get_bits1(&s->gb);
514 run = get_bits(&s->gb, 6);
515 level = (int8_t)get_bits(&s->gb, 8);
517 if (s->codec_id == AV_CODEC_ID_RV10) {
518 /* XXX: should patch encoder too */
519 level = get_sbits(&s->gb, 12);
521 level = get_bits(&s->gb, 5);
522 level |= get_sbits(&s->gb, 6)<<5;
527 run = rl->table_run[code];
528 level = rl->table_level[code];
529 last = code >= rl->last;
530 if (get_bits1(&s->gb))
535 if(s->alt_inter_vlc && rl == &ff_h263_rl_inter && !s->mb_intra){
536 //Looks like a hack but no, it's the way it is supposed to work ...
537 rl = &ff_rl_intra_aic;
540 s->dsp.clear_block(block);
543 av_log(s->avctx, AV_LOG_ERROR, "run overflow at %dx%d i:%d\n", s->mb_x, s->mb_y, s->mb_intra);
553 if (s->mb_intra && s->h263_aic) {
554 ff_h263_pred_acdc(s, block, n);
557 s->block_last_index[n] = i;
561 static int h263_skip_b_part(MpegEncContext *s, int cbp)
563 LOCAL_ALIGNED_16(int16_t, dblock, [64]);
566 /* we have to set s->mb_intra to zero to decode B-part of PB-frame correctly
567 * but real value should be restored in order to be used later (in OBMC condition)
571 for (i = 0; i < 6; i++) {
572 if (h263_decode_block(s, dblock, i, cbp&32) < 0)
580 static int h263_get_modb(GetBitContext *gb, int pb_frame, int *cbpb)
584 if (pb_frame < 3) { // h.263 Annex G and i263 PB-frame
586 if (pb_frame == 2 && c)
588 } else { // h.263 Annex M improved PB-frame
589 mv = get_unary(gb, 0, 4) + 1;
594 *cbpb = get_bits(gb, 6);
598 int ff_h263_decode_mb(MpegEncContext *s,
599 int16_t block[6][64])
601 int cbpc, cbpy, i, cbp, pred_x, pred_y, mx, my, dquant;
603 const int xy= s->mb_x + s->mb_y * s->mb_stride;
604 int cbpb = 0, pb_mv_count = 0;
606 assert(!s->h263_pred);
608 if (s->pict_type == AV_PICTURE_TYPE_P) {
610 if (get_bits1(&s->gb)) {
614 s->block_last_index[i] = -1;
615 s->mv_dir = MV_DIR_FORWARD;
616 s->mv_type = MV_TYPE_16X16;
617 s->current_picture.mb_type[xy] = MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
620 s->mb_skipped = !(s->obmc | s->loop_filter);
623 cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
625 av_log(s->avctx, AV_LOG_ERROR, "cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
630 s->dsp.clear_blocks(s->block[0]);
633 s->mb_intra = ((cbpc & 4) != 0);
634 if (s->mb_intra) goto intra;
636 if(s->pb_frame && get_bits1(&s->gb))
637 pb_mv_count = h263_get_modb(&s->gb, s->pb_frame, &cbpb);
638 cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
640 if(s->alt_inter_vlc==0 || (cbpc & 3)!=3)
643 cbp = (cbpc & 3) | (cbpy << 2);
645 h263_decode_dquant(s);
648 s->mv_dir = MV_DIR_FORWARD;
649 if ((cbpc & 16) == 0) {
650 s->current_picture.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
651 /* 16x16 motion prediction */
652 s->mv_type = MV_TYPE_16X16;
653 ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
655 mx = h263p_decode_umotion(s, pred_x);
657 mx = ff_h263_decode_motion(s, pred_x, 1);
663 my = h263p_decode_umotion(s, pred_y);
665 my = ff_h263_decode_motion(s, pred_y, 1);
672 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
673 skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
675 s->current_picture.mb_type[xy] = MB_TYPE_8x8 | MB_TYPE_L0;
676 s->mv_type = MV_TYPE_8X8;
678 mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
680 mx = h263p_decode_umotion(s, pred_x);
682 mx = ff_h263_decode_motion(s, pred_x, 1);
687 my = h263p_decode_umotion(s, pred_y);
689 my = ff_h263_decode_motion(s, pred_y, 1);
694 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
695 skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
700 } else if(s->pict_type==AV_PICTURE_TYPE_B) {
702 const int stride= s->b8_stride;
703 int16_t *mot_val0 = s->current_picture.motion_val[0][2 * (s->mb_x + s->mb_y * stride)];
704 int16_t *mot_val1 = s->current_picture.motion_val[1][2 * (s->mb_x + s->mb_y * stride)];
705 // const int mv_xy= s->mb_x + 1 + s->mb_y * s->mb_stride;
708 mot_val0[0 ]= mot_val0[2 ]= mot_val0[0+2*stride]= mot_val0[2+2*stride]=
709 mot_val0[1 ]= mot_val0[3 ]= mot_val0[1+2*stride]= mot_val0[3+2*stride]=
710 mot_val1[0 ]= mot_val1[2 ]= mot_val1[0+2*stride]= mot_val1[2+2*stride]=
711 mot_val1[1 ]= mot_val1[3 ]= mot_val1[1+2*stride]= mot_val1[3+2*stride]= 0;
714 mb_type= get_vlc2(&s->gb, h263_mbtype_b_vlc.table, H263_MBTYPE_B_VLC_BITS, 2);
716 av_log(s->avctx, AV_LOG_ERROR, "b mb_type damaged at %d %d\n", s->mb_x, s->mb_y);
720 mb_type= h263_mb_type_b_map[ mb_type ];
723 s->mb_intra = IS_INTRA(mb_type);
724 if(HAS_CBP(mb_type)){
725 s->dsp.clear_blocks(s->block[0]);
726 cbpc = get_vlc2(&s->gb, cbpc_b_vlc.table, CBPC_B_VLC_BITS, 1);
728 dquant = IS_QUANT(mb_type);
732 cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
735 av_log(s->avctx, AV_LOG_ERROR, "b cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
739 if(s->alt_inter_vlc==0 || (cbpc & 3)!=3)
742 cbp = (cbpc & 3) | (cbpy << 2);
746 assert(!s->mb_intra);
748 if(IS_QUANT(mb_type)){
749 h263_decode_dquant(s);
752 if(IS_DIRECT(mb_type)){
753 s->mv_dir = MV_DIR_FORWARD | MV_DIR_BACKWARD | MV_DIRECT;
754 mb_type |= ff_mpeg4_set_direct_mv(s, 0, 0);
757 s->mv_type= MV_TYPE_16X16;
760 if(USES_LIST(mb_type, 0)){
761 int16_t *mot_val= ff_h263_pred_motion(s, 0, 0, &mx, &my);
762 s->mv_dir = MV_DIR_FORWARD;
764 mx = ff_h263_decode_motion(s, mx, 1);
765 my = ff_h263_decode_motion(s, my, 1);
769 mot_val[0 ]= mot_val[2 ]= mot_val[0+2*stride]= mot_val[2+2*stride]= mx;
770 mot_val[1 ]= mot_val[3 ]= mot_val[1+2*stride]= mot_val[3+2*stride]= my;
773 if(USES_LIST(mb_type, 1)){
774 int16_t *mot_val= ff_h263_pred_motion(s, 0, 1, &mx, &my);
775 s->mv_dir |= MV_DIR_BACKWARD;
777 mx = ff_h263_decode_motion(s, mx, 1);
778 my = ff_h263_decode_motion(s, my, 1);
782 mot_val[0 ]= mot_val[2 ]= mot_val[0+2*stride]= mot_val[2+2*stride]= mx;
783 mot_val[1 ]= mot_val[3 ]= mot_val[1+2*stride]= mot_val[3+2*stride]= my;
787 s->current_picture.mb_type[xy] = mb_type;
788 } else { /* I-Frame */
790 cbpc = get_vlc2(&s->gb, ff_h263_intra_MCBPC_vlc.table, INTRA_MCBPC_VLC_BITS, 2);
792 av_log(s->avctx, AV_LOG_ERROR, "I cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
797 s->dsp.clear_blocks(s->block[0]);
802 s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
804 s->ac_pred = get_bits1(&s->gb);
806 s->current_picture.mb_type[xy] = MB_TYPE_INTRA | MB_TYPE_ACPRED;
808 s->h263_aic_dir = get_bits1(&s->gb);
813 if(s->pb_frame && get_bits1(&s->gb))
814 pb_mv_count = h263_get_modb(&s->gb, s->pb_frame, &cbpb);
815 cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
817 av_log(s->avctx, AV_LOG_ERROR, "I cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
820 cbp = (cbpc & 3) | (cbpy << 2);
822 h263_decode_dquant(s);
825 pb_mv_count += !!s->pb_frame;
828 while(pb_mv_count--){
829 ff_h263_decode_motion(s, 0, 1);
830 ff_h263_decode_motion(s, 0, 1);
833 /* decode each block */
834 for (i = 0; i < 6; i++) {
835 if (h263_decode_block(s, block[i], i, cbp&32) < 0)
840 if(s->pb_frame && h263_skip_b_part(s, cbpb) < 0)
842 if(s->obmc && !s->mb_intra){
843 if(s->pict_type == AV_PICTURE_TYPE_P && s->mb_x+1<s->mb_width && s->mb_num_left != 1)
848 /* per-MB end of slice check */
850 int v= show_bits(&s->gb, 16);
852 if (get_bits_left(&s->gb) < 16) {
853 v >>= 16 - get_bits_left(&s->gb);
863 /* most is hardcoded. should extend to handle all h263 streams */
864 int ff_h263_decode_picture_header(MpegEncContext *s)
866 int format, width, height, i;
869 align_get_bits(&s->gb);
871 startcode= get_bits(&s->gb, 22-8);
873 for(i= get_bits_left(&s->gb); i>24; i-=8) {
874 startcode = ((startcode << 8) | get_bits(&s->gb, 8)) & 0x003FFFFF;
876 if(startcode == 0x20)
880 if (startcode != 0x20) {
881 av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
884 /* temporal reference */
885 i = get_bits(&s->gb, 8); /* picture timestamp */
886 if( (s->picture_number&~0xFF)+i < s->picture_number)
888 s->current_picture_ptr->f.pts =
889 s->picture_number= (s->picture_number&~0xFF) + i;
891 /* PTYPE starts here */
892 if (get_bits1(&s->gb) != 1) {
894 av_log(s->avctx, AV_LOG_ERROR, "Bad marker\n");
897 if (get_bits1(&s->gb) != 0) {
898 av_log(s->avctx, AV_LOG_ERROR, "Bad H263 id\n");
899 return -1; /* h263 id */
901 skip_bits1(&s->gb); /* split screen off */
902 skip_bits1(&s->gb); /* camera off */
903 skip_bits1(&s->gb); /* freeze picture release off */
905 format = get_bits(&s->gb, 3);
910 7 extended PTYPE (PLUSPTYPE)
913 if (format != 7 && format != 6) {
916 width = ff_h263_format[format][0];
917 height = ff_h263_format[format][1];
921 s->pict_type = AV_PICTURE_TYPE_I + get_bits1(&s->gb);
923 s->h263_long_vectors = get_bits1(&s->gb);
925 if (get_bits1(&s->gb) != 0) {
926 av_log(s->avctx, AV_LOG_ERROR, "H263 SAC not supported\n");
927 return -1; /* SAC: off */
929 s->obmc= get_bits1(&s->gb); /* Advanced prediction mode */
930 s->unrestricted_mv = s->h263_long_vectors || s->obmc;
932 s->pb_frame = get_bits1(&s->gb);
933 s->chroma_qscale= s->qscale = get_bits(&s->gb, 5);
934 skip_bits1(&s->gb); /* Continuous Presence Multipoint mode: off */
938 s->avctx->sample_aspect_ratio= (AVRational){12,11};
939 s->avctx->time_base= (AVRational){1001, 30000};
945 ufep = get_bits(&s->gb, 3); /* Update Full Extended PTYPE */
947 /* ufep other than 0 and 1 are reserved */
950 format = get_bits(&s->gb, 3);
951 av_dlog(s->avctx, "ufep=1, format: %d\n", format);
952 s->custom_pcf= get_bits1(&s->gb);
953 s->umvplus = get_bits1(&s->gb); /* Unrestricted Motion Vector */
954 if (get_bits1(&s->gb) != 0) {
955 av_log(s->avctx, AV_LOG_ERROR, "Syntax-based Arithmetic Coding (SAC) not supported\n");
957 s->obmc= get_bits1(&s->gb); /* Advanced prediction mode */
958 s->h263_aic = get_bits1(&s->gb); /* Advanced Intra Coding (AIC) */
959 s->loop_filter= get_bits1(&s->gb);
960 s->unrestricted_mv = s->umvplus || s->obmc || s->loop_filter;
962 s->h263_slice_structured= get_bits1(&s->gb);
963 if (get_bits1(&s->gb) != 0) {
964 av_log(s->avctx, AV_LOG_ERROR, "Reference Picture Selection not supported\n");
966 if (get_bits1(&s->gb) != 0) {
967 av_log(s->avctx, AV_LOG_ERROR, "Independent Segment Decoding not supported\n");
969 s->alt_inter_vlc= get_bits1(&s->gb);
970 s->modified_quant= get_bits1(&s->gb);
971 if(s->modified_quant)
972 s->chroma_qscale_table= ff_h263_chroma_qscale_table;
974 skip_bits(&s->gb, 1); /* Prevent start code emulation */
976 skip_bits(&s->gb, 3); /* Reserved */
977 } else if (ufep != 0) {
978 av_log(s->avctx, AV_LOG_ERROR, "Bad UFEP type (%d)\n", ufep);
983 s->pict_type = get_bits(&s->gb, 3);
984 switch(s->pict_type){
985 case 0: s->pict_type= AV_PICTURE_TYPE_I;break;
986 case 1: s->pict_type= AV_PICTURE_TYPE_P;break;
987 case 2: s->pict_type= AV_PICTURE_TYPE_P;s->pb_frame = 3;break;
988 case 3: s->pict_type= AV_PICTURE_TYPE_B;break;
989 case 7: s->pict_type= AV_PICTURE_TYPE_I;break; //ZYGO
993 skip_bits(&s->gb, 2);
994 s->no_rounding = get_bits1(&s->gb);
995 skip_bits(&s->gb, 4);
997 /* Get the picture dimensions */
1000 /* Custom Picture Format (CPFMT) */
1001 s->aspect_ratio_info = get_bits(&s->gb, 4);
1002 av_dlog(s->avctx, "aspect: %d\n", s->aspect_ratio_info);
1007 3 - 10:11 (525-type 4:3)
1008 4 - 16:11 (CIF 16:9)
1009 5 - 40:33 (525-type 16:9)
1012 width = (get_bits(&s->gb, 9) + 1) * 4;
1014 height = get_bits(&s->gb, 9) * 4;
1015 av_dlog(s->avctx, "\nH.263+ Custom picture: %dx%d\n",width,height);
1016 if (s->aspect_ratio_info == FF_ASPECT_EXTENDED) {
1017 /* aspected dimensions */
1018 s->avctx->sample_aspect_ratio.num= get_bits(&s->gb, 8);
1019 s->avctx->sample_aspect_ratio.den= get_bits(&s->gb, 8);
1021 s->avctx->sample_aspect_ratio= ff_h263_pixel_aspect[s->aspect_ratio_info];
1024 width = ff_h263_format[format][0];
1025 height = ff_h263_format[format][1];
1026 s->avctx->sample_aspect_ratio= (AVRational){12,11};
1028 if ((width == 0) || (height == 0))
1035 s->avctx->time_base.den= 1800000;
1036 s->avctx->time_base.num= 1000 + get_bits1(&s->gb);
1037 s->avctx->time_base.num*= get_bits(&s->gb, 7);
1038 if(s->avctx->time_base.num == 0){
1039 av_log(s, AV_LOG_ERROR, "zero framerate\n");
1042 gcd= av_gcd(s->avctx->time_base.den, s->avctx->time_base.num);
1043 s->avctx->time_base.den /= gcd;
1044 s->avctx->time_base.num /= gcd;
1046 s->avctx->time_base= (AVRational){1001, 30000};
1051 skip_bits(&s->gb, 2); //extended Temporal reference
1056 if(get_bits1(&s->gb)==0) /* Unlimited Unrestricted Motion Vectors Indicator (UUI) */
1059 if(s->h263_slice_structured){
1060 if (get_bits1(&s->gb) != 0) {
1061 av_log(s->avctx, AV_LOG_ERROR, "rectangular slices not supported\n");
1063 if (get_bits1(&s->gb) != 0) {
1064 av_log(s->avctx, AV_LOG_ERROR, "unordered slices not supported\n");
1069 s->qscale = get_bits(&s->gb, 5);
1072 s->mb_width = (s->width + 15) / 16;
1073 s->mb_height = (s->height + 15) / 16;
1074 s->mb_num = s->mb_width * s->mb_height;
1077 skip_bits(&s->gb, 3); /* Temporal reference for B-pictures */
1079 skip_bits(&s->gb, 2); //extended Temporal reference
1080 skip_bits(&s->gb, 2); /* Quantization information for B-pictures */
1083 if (s->pict_type!=AV_PICTURE_TYPE_B) {
1084 s->time = s->picture_number;
1085 s->pp_time = s->time - s->last_non_b_time;
1086 s->last_non_b_time = s->time;
1088 s->time = s->picture_number;
1089 s->pb_time = s->pp_time - (s->last_non_b_time - s->time);
1090 if (s->pp_time <=s->pb_time ||
1091 s->pp_time <= s->pp_time - s->pb_time ||
1096 ff_mpeg4_init_direct_mv(s);
1100 while (get_bits1(&s->gb) != 0) {
1101 skip_bits(&s->gb, 8);
1104 if(s->h263_slice_structured){
1105 if (get_bits1(&s->gb) != 1) {
1106 av_log(s->avctx, AV_LOG_ERROR, "SEPB1 marker missing\n");
1110 ff_h263_decode_mba(s);
1112 if (get_bits1(&s->gb) != 1) {
1113 av_log(s->avctx, AV_LOG_ERROR, "SEPB2 marker missing\n");
1120 s->y_dc_scale_table=
1121 s->c_dc_scale_table= ff_aic_dc_scale_table;
1123 s->y_dc_scale_table=
1124 s->c_dc_scale_table= ff_mpeg1_dc_scale_table;
1127 ff_h263_show_pict_info(s);
1128 if (s->pict_type == AV_PICTURE_TYPE_I && s->codec_tag == AV_RL32("ZYGO")){
1130 for(i=0; i<85; i++) av_log(s->avctx, AV_LOG_DEBUG, "%d", get_bits1(&s->gb));
1131 av_log(s->avctx, AV_LOG_DEBUG, "\n");
1132 for(i=0; i<13; i++){
1134 int v= get_bits(&s->gb, 8);
1135 v |= get_sbits(&s->gb, 8)<<8;
1136 av_log(s->avctx, AV_LOG_DEBUG, " %5d", v);
1138 av_log(s->avctx, AV_LOG_DEBUG, "\n");
1140 for(i=0; i<50; i++) av_log(s->avctx, AV_LOG_DEBUG, "%d", get_bits1(&s->gb));