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"
48 // The defines below define the number of bits that are read at once for
49 // reading vlc values. Changing these may improve speed and data cache needs
50 // be aware though that decreasing them may need the number of stages that is
51 // passed to get_vlc* to be increased.
53 #define H263_MBTYPE_B_VLC_BITS 6
54 #define CBPC_B_VLC_BITS 3
56 static const int h263_mb_type_b_map[15]= {
57 MB_TYPE_DIRECT2 | MB_TYPE_L0L1,
58 MB_TYPE_DIRECT2 | MB_TYPE_L0L1 | MB_TYPE_CBP,
59 MB_TYPE_DIRECT2 | MB_TYPE_L0L1 | MB_TYPE_CBP | MB_TYPE_QUANT,
60 MB_TYPE_L0 | MB_TYPE_16x16,
61 MB_TYPE_L0 | MB_TYPE_CBP | MB_TYPE_16x16,
62 MB_TYPE_L0 | MB_TYPE_CBP | MB_TYPE_QUANT | MB_TYPE_16x16,
63 MB_TYPE_L1 | MB_TYPE_16x16,
64 MB_TYPE_L1 | MB_TYPE_CBP | MB_TYPE_16x16,
65 MB_TYPE_L1 | MB_TYPE_CBP | MB_TYPE_QUANT | MB_TYPE_16x16,
66 MB_TYPE_L0L1 | MB_TYPE_16x16,
67 MB_TYPE_L0L1 | MB_TYPE_CBP | MB_TYPE_16x16,
68 MB_TYPE_L0L1 | MB_TYPE_CBP | MB_TYPE_QUANT | MB_TYPE_16x16,
70 MB_TYPE_INTRA4x4 | MB_TYPE_CBP,
71 MB_TYPE_INTRA4x4 | MB_TYPE_CBP | MB_TYPE_QUANT,
74 void ff_h263_show_pict_info(MpegEncContext *s){
75 if(s->avctx->debug&FF_DEBUG_PICT_INFO){
76 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",
77 s->qscale, av_get_picture_type_char(s->pict_type),
78 s->gb.size_in_bits, 1-s->no_rounding,
80 s->umvplus ? " UMV" : "",
81 s->h263_long_vectors ? " LONG" : "",
82 s->h263_plus ? " +" : "",
83 s->h263_aic ? " AIC" : "",
84 s->alt_inter_vlc ? " AIV" : "",
85 s->modified_quant ? " MQ" : "",
86 s->loop_filter ? " LOOP" : "",
87 s->h263_slice_structured ? " SS" : "",
88 s->avctx->time_base.den, s->avctx->time_base.num
93 /***********************************************/
96 VLC ff_h263_intra_MCBPC_vlc;
97 VLC ff_h263_inter_MCBPC_vlc;
100 static VLC h263_mbtype_b_vlc;
101 static VLC cbpc_b_vlc;
105 /* XXX: find a better solution to handle static init */
106 void h263_decode_init_vlc(MpegEncContext *s)
113 INIT_VLC_STATIC(&ff_h263_intra_MCBPC_vlc, INTRA_MCBPC_VLC_BITS, 9,
114 ff_h263_intra_MCBPC_bits, 1, 1,
115 ff_h263_intra_MCBPC_code, 1, 1, 72);
116 INIT_VLC_STATIC(&ff_h263_inter_MCBPC_vlc, INTER_MCBPC_VLC_BITS, 28,
117 ff_h263_inter_MCBPC_bits, 1, 1,
118 ff_h263_inter_MCBPC_code, 1, 1, 198);
119 INIT_VLC_STATIC(&ff_h263_cbpy_vlc, CBPY_VLC_BITS, 16,
120 &ff_h263_cbpy_tab[0][1], 2, 1,
121 &ff_h263_cbpy_tab[0][0], 2, 1, 64);
122 INIT_VLC_STATIC(&mv_vlc, MV_VLC_BITS, 33,
124 &mvtab[0][0], 2, 1, 538);
125 init_rl(&ff_h263_rl_inter, ff_h263_static_rl_table_store[0]);
126 init_rl(&rl_intra_aic, ff_h263_static_rl_table_store[1]);
127 INIT_VLC_RL(ff_h263_rl_inter, 554);
128 INIT_VLC_RL(rl_intra_aic, 554);
129 INIT_VLC_STATIC(&h263_mbtype_b_vlc, H263_MBTYPE_B_VLC_BITS, 15,
130 &h263_mbtype_b_tab[0][1], 2, 1,
131 &h263_mbtype_b_tab[0][0], 2, 1, 80);
132 INIT_VLC_STATIC(&cbpc_b_vlc, CBPC_B_VLC_BITS, 4,
133 &cbpc_b_tab[0][1], 2, 1,
134 &cbpc_b_tab[0][0], 2, 1, 8);
138 int ff_h263_decode_mba(MpegEncContext *s)
143 if(s->mb_num-1 <= ff_mba_max[i]) break;
145 mb_pos= get_bits(&s->gb, ff_mba_length[i]);
146 s->mb_x= mb_pos % s->mb_width;
147 s->mb_y= mb_pos / s->mb_width;
153 * Decode the group of blocks header or slice header.
154 * @return <0 if an error occurred
156 static int h263_decode_gob_header(MpegEncContext *s)
158 unsigned int val, gob_number;
161 /* Check for GOB Start Code */
162 val = show_bits(&s->gb, 16);
166 /* We have a GBSC probably with GSTUFF */
167 skip_bits(&s->gb, 16); /* Drop the zeros */
168 left= get_bits_left(&s->gb);
169 //MN: we must check the bits left or we might end in a infinite loop (or segfault)
170 for(;left>13; left--){
171 if(get_bits1(&s->gb)) break; /* Seek the '1' bit */
176 if(s->h263_slice_structured){
177 if(get_bits1(&s->gb)==0)
180 ff_h263_decode_mba(s);
183 if(get_bits1(&s->gb)==0)
186 s->qscale = get_bits(&s->gb, 5); /* SQUANT */
187 if(get_bits1(&s->gb)==0)
189 skip_bits(&s->gb, 2); /* GFID */
191 gob_number = get_bits(&s->gb, 5); /* GN */
193 s->mb_y= s->gob_index* gob_number;
194 skip_bits(&s->gb, 2); /* GFID */
195 s->qscale = get_bits(&s->gb, 5); /* GQUANT */
198 if(s->mb_y >= s->mb_height)
208 * Find the next resync_marker.
209 * @param p pointer to buffer to scan
210 * @param end pointer to the end of the buffer
211 * @return pointer to the next resync_marker, or end if none was found
213 const uint8_t *ff_h263_find_resync_marker(const uint8_t *restrict p, const uint8_t * restrict end)
221 if (!p[-1] && p[1]) return p - 1;
222 else if(!p[ 1] && p[2]) return p;
229 * Decode the group of blocks / video packet header.
230 * @return bit position of the resync_marker, or <0 if none was found
232 int ff_h263_resync(MpegEncContext *s){
235 if(s->codec_id==CODEC_ID_MPEG4){
237 align_get_bits(&s->gb);
240 if(show_bits(&s->gb, 16)==0){
241 pos= get_bits_count(&s->gb);
242 if(CONFIG_MPEG4_DECODER && s->codec_id==CODEC_ID_MPEG4)
243 ret= mpeg4_decode_video_packet_header(s);
245 ret= h263_decode_gob_header(s);
249 //OK, it's not where it is supposed to be ...
250 s->gb= s->last_resync_gb;
251 align_get_bits(&s->gb);
252 left= get_bits_left(&s->gb);
254 for(;left>16+1+5+5; left-=8){
255 if(show_bits(&s->gb, 16)==0){
256 GetBitContext bak= s->gb;
258 pos= get_bits_count(&s->gb);
259 if(CONFIG_MPEG4_DECODER && s->codec_id==CODEC_ID_MPEG4)
260 ret= mpeg4_decode_video_packet_header(s);
262 ret= h263_decode_gob_header(s);
268 skip_bits(&s->gb, 8);
274 int h263_decode_motion(MpegEncContext * s, int pred, int f_code)
276 int code, val, sign, shift;
277 code = get_vlc2(&s->gb, mv_vlc.table, MV_VLC_BITS, 2);
284 sign = get_bits1(&s->gb);
288 val = (val - 1) << shift;
289 val |= get_bits(&s->gb, shift);
296 /* modulo decoding */
297 if (!s->h263_long_vectors) {
298 val = sign_extend(val, 5 + f_code);
300 /* horrible h263 long vector mode */
301 if (pred < -31 && val < -63)
303 if (pred > 32 && val > 63)
311 /* Decode RVLC of H.263+ UMV */
312 static int h263p_decode_umotion(MpegEncContext * s, int pred)
316 if (get_bits1(&s->gb)) /* Motion difference = 0 */
319 code = 2 + get_bits1(&s->gb);
321 while (get_bits1(&s->gb))
324 code += get_bits1(&s->gb);
329 code = (sign) ? (pred - code) : (pred + code);
330 av_dlog(s->avctx,"H.263+ UMV Motion = %d\n", code);
336 * read the next MVs for OBMC. yes this is a ugly hack, feel free to send a patch :)
338 static void preview_obmc(MpegEncContext *s){
339 GetBitContext gb= s->gb;
341 int cbpc, i, pred_x, pred_y, mx, my;
343 const int xy= s->mb_x + 1 + s->mb_y * s->mb_stride;
344 const int stride= s->b8_stride*2;
347 s->block_index[i]+= 2;
349 s->block_index[i]+= 1;
352 assert(s->pict_type == AV_PICTURE_TYPE_P);
355 if (get_bits1(&s->gb)) {
357 mot_val = s->current_picture.f.motion_val[0][s->block_index[0]];
358 mot_val[0 ]= mot_val[2 ]=
359 mot_val[0+stride]= mot_val[2+stride]= 0;
360 mot_val[1 ]= mot_val[3 ]=
361 mot_val[1+stride]= mot_val[3+stride]= 0;
363 s->current_picture.f.mb_type[xy] = MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
366 cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
370 s->current_picture.f.mb_type[xy] = MB_TYPE_INTRA;
372 get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
374 if(s->modified_quant){
375 if(get_bits1(&s->gb)) skip_bits(&s->gb, 1);
376 else skip_bits(&s->gb, 5);
378 skip_bits(&s->gb, 2);
381 if ((cbpc & 16) == 0) {
382 s->current_picture.f.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
383 /* 16x16 motion prediction */
384 mot_val= h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
386 mx = h263p_decode_umotion(s, pred_x);
388 mx = h263_decode_motion(s, pred_x, 1);
391 my = h263p_decode_umotion(s, pred_y);
393 my = h263_decode_motion(s, pred_y, 1);
395 mot_val[0 ]= mot_val[2 ]=
396 mot_val[0+stride]= mot_val[2+stride]= mx;
397 mot_val[1 ]= mot_val[3 ]=
398 mot_val[1+stride]= mot_val[3+stride]= my;
400 s->current_picture.f.mb_type[xy] = MB_TYPE_8x8 | MB_TYPE_L0;
402 mot_val = h263_pred_motion(s, i, 0, &pred_x, &pred_y);
404 mx = h263p_decode_umotion(s, pred_x);
406 mx = h263_decode_motion(s, pred_x, 1);
409 my = h263p_decode_umotion(s, pred_y);
411 my = h263_decode_motion(s, pred_y, 1);
412 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
413 skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
422 s->block_index[i]-= 2;
424 s->block_index[i]-= 1;
430 static void h263_decode_dquant(MpegEncContext *s){
431 static const int8_t quant_tab[4] = { -1, -2, 1, 2 };
433 if(s->modified_quant){
434 if(get_bits1(&s->gb))
435 s->qscale= modified_quant_tab[get_bits1(&s->gb)][ s->qscale ];
437 s->qscale= get_bits(&s->gb, 5);
439 s->qscale += quant_tab[get_bits(&s->gb, 2)];
440 ff_set_qscale(s, s->qscale);
443 static int h263_decode_block(MpegEncContext * s, DCTELEM * block,
446 int code, level, i, j, last, run;
447 RLTable *rl = &ff_h263_rl_inter;
448 const uint8_t *scan_table;
449 GetBitContext gb= s->gb;
451 scan_table = s->intra_scantable.permutated;
452 if (s->h263_aic && s->mb_intra) {
457 scan_table = s->intra_v_scantable.permutated; /* left */
459 scan_table = s->intra_h_scantable.permutated; /* top */
461 } else if (s->mb_intra) {
463 if(s->codec_id == CODEC_ID_RV10){
464 #if CONFIG_RV10_DECODER
465 if (s->rv10_version == 3 && s->pict_type == AV_PICTURE_TYPE_I) {
467 component = (n <= 3 ? 0 : n - 4 + 1);
468 level = s->last_dc[component];
469 if (s->rv10_first_dc_coded[component]) {
470 diff = rv_decode_dc(s, n);
474 level = level & 0xff; /* handle wrap round */
475 s->last_dc[component] = level;
477 s->rv10_first_dc_coded[component] = 1;
480 level = get_bits(&s->gb, 8);
486 level = get_bits(&s->gb, 8);
487 if((level&0x7F) == 0){
488 av_log(s->avctx, AV_LOG_ERROR, "illegal dc %d at %d %d\n", level, s->mb_x, s->mb_y);
489 if(s->err_recognition & (AV_EF_BITSTREAM|AV_EF_COMPLIANT))
501 if (s->mb_intra && s->h263_aic)
503 s->block_last_index[n] = i - 1;
508 code = get_vlc2(&s->gb, rl->vlc.table, TEX_VLC_BITS, 2);
510 av_log(s->avctx, AV_LOG_ERROR, "illegal ac vlc code at %dx%d\n", s->mb_x, s->mb_y);
515 if (CONFIG_FLV_DECODER && s->h263_flv > 1) {
516 ff_flv2_decode_ac_esc(&s->gb, &level, &run, &last);
518 last = get_bits1(&s->gb);
519 run = get_bits(&s->gb, 6);
520 level = (int8_t)get_bits(&s->gb, 8);
522 if (s->codec_id == CODEC_ID_RV10) {
523 /* XXX: should patch encoder too */
524 level = get_sbits(&s->gb, 12);
526 level = get_bits(&s->gb, 5);
527 level |= get_sbits(&s->gb, 6)<<5;
532 run = rl->table_run[code];
533 level = rl->table_level[code];
534 last = code >= rl->last;
535 if (get_bits1(&s->gb))
540 if(s->alt_inter_vlc && rl == &ff_h263_rl_inter && !s->mb_intra){
541 //Looks like a hack but no, it's the way it is supposed to work ...
545 s->dsp.clear_block(block);
548 av_log(s->avctx, AV_LOG_ERROR, "run overflow at %dx%d i:%d\n", s->mb_x, s->mb_y, s->mb_intra);
558 if (s->mb_intra && s->h263_aic) {
559 h263_pred_acdc(s, block, n);
562 s->block_last_index[n] = i;
566 static int h263_skip_b_part(MpegEncContext *s, int cbp)
568 LOCAL_ALIGNED_16(DCTELEM, dblock, [64]);
571 /* we have to set s->mb_intra to zero to decode B-part of PB-frame correctly
572 * but real value should be restored in order to be used later (in OBMC condition)
576 for (i = 0; i < 6; i++) {
577 if (h263_decode_block(s, dblock, i, cbp&32) < 0)
585 static int h263_get_modb(GetBitContext *gb, int pb_frame, int *cbpb)
589 if (pb_frame < 3) { // h.263 Annex G and i263 PB-frame
591 if (pb_frame == 2 && c)
593 } else { // h.263 Annex M improved PB-frame
594 mv = get_unary(gb, 0, 4) + 1;
599 *cbpb = get_bits(gb, 6);
603 int ff_h263_decode_mb(MpegEncContext *s,
604 DCTELEM block[6][64])
606 int cbpc, cbpy, i, cbp, pred_x, pred_y, mx, my, dquant;
608 const int xy= s->mb_x + s->mb_y * s->mb_stride;
609 int cbpb = 0, pb_mv_count = 0;
611 assert(!s->h263_pred);
613 if (s->pict_type == AV_PICTURE_TYPE_P) {
615 if (get_bits1(&s->gb)) {
619 s->block_last_index[i] = -1;
620 s->mv_dir = MV_DIR_FORWARD;
621 s->mv_type = MV_TYPE_16X16;
622 s->current_picture.f.mb_type[xy] = MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
625 s->mb_skipped = !(s->obmc | s->loop_filter);
628 cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
630 av_log(s->avctx, AV_LOG_ERROR, "cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
635 s->dsp.clear_blocks(s->block[0]);
638 s->mb_intra = ((cbpc & 4) != 0);
639 if (s->mb_intra) goto intra;
641 if(s->pb_frame && get_bits1(&s->gb))
642 pb_mv_count = h263_get_modb(&s->gb, s->pb_frame, &cbpb);
643 cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
645 if(s->alt_inter_vlc==0 || (cbpc & 3)!=3)
648 cbp = (cbpc & 3) | (cbpy << 2);
650 h263_decode_dquant(s);
653 s->mv_dir = MV_DIR_FORWARD;
654 if ((cbpc & 16) == 0) {
655 s->current_picture.f.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
656 /* 16x16 motion prediction */
657 s->mv_type = MV_TYPE_16X16;
658 h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
660 mx = h263p_decode_umotion(s, pred_x);
662 mx = h263_decode_motion(s, pred_x, 1);
668 my = h263p_decode_umotion(s, pred_y);
670 my = h263_decode_motion(s, pred_y, 1);
677 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
678 skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
680 s->current_picture.f.mb_type[xy] = MB_TYPE_8x8 | MB_TYPE_L0;
681 s->mv_type = MV_TYPE_8X8;
683 mot_val = h263_pred_motion(s, i, 0, &pred_x, &pred_y);
685 mx = h263p_decode_umotion(s, pred_x);
687 mx = h263_decode_motion(s, pred_x, 1);
692 my = h263p_decode_umotion(s, pred_y);
694 my = h263_decode_motion(s, pred_y, 1);
699 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
700 skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
705 } else if(s->pict_type==AV_PICTURE_TYPE_B) {
707 const int stride= s->b8_stride;
708 int16_t *mot_val0 = s->current_picture.f.motion_val[0][2 * (s->mb_x + s->mb_y * stride)];
709 int16_t *mot_val1 = s->current_picture.f.motion_val[1][2 * (s->mb_x + s->mb_y * stride)];
710 // const int mv_xy= s->mb_x + 1 + s->mb_y * s->mb_stride;
713 mot_val0[0 ]= mot_val0[2 ]= mot_val0[0+2*stride]= mot_val0[2+2*stride]=
714 mot_val0[1 ]= mot_val0[3 ]= mot_val0[1+2*stride]= mot_val0[3+2*stride]=
715 mot_val1[0 ]= mot_val1[2 ]= mot_val1[0+2*stride]= mot_val1[2+2*stride]=
716 mot_val1[1 ]= mot_val1[3 ]= mot_val1[1+2*stride]= mot_val1[3+2*stride]= 0;
719 mb_type= get_vlc2(&s->gb, h263_mbtype_b_vlc.table, H263_MBTYPE_B_VLC_BITS, 2);
721 av_log(s->avctx, AV_LOG_ERROR, "b mb_type damaged at %d %d\n", s->mb_x, s->mb_y);
725 mb_type= h263_mb_type_b_map[ mb_type ];
728 s->mb_intra = IS_INTRA(mb_type);
729 if(HAS_CBP(mb_type)){
730 s->dsp.clear_blocks(s->block[0]);
731 cbpc = get_vlc2(&s->gb, cbpc_b_vlc.table, CBPC_B_VLC_BITS, 1);
733 dquant = IS_QUANT(mb_type);
737 cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
740 av_log(s->avctx, AV_LOG_ERROR, "b cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
744 if(s->alt_inter_vlc==0 || (cbpc & 3)!=3)
747 cbp = (cbpc & 3) | (cbpy << 2);
751 assert(!s->mb_intra);
753 if(IS_QUANT(mb_type)){
754 h263_decode_dquant(s);
757 if(IS_DIRECT(mb_type)){
758 s->mv_dir = MV_DIR_FORWARD | MV_DIR_BACKWARD | MV_DIRECT;
759 mb_type |= ff_mpeg4_set_direct_mv(s, 0, 0);
762 s->mv_type= MV_TYPE_16X16;
765 if(USES_LIST(mb_type, 0)){
766 int16_t *mot_val= h263_pred_motion(s, 0, 0, &mx, &my);
767 s->mv_dir = MV_DIR_FORWARD;
769 mx = h263_decode_motion(s, mx, 1);
770 my = h263_decode_motion(s, my, 1);
774 mot_val[0 ]= mot_val[2 ]= mot_val[0+2*stride]= mot_val[2+2*stride]= mx;
775 mot_val[1 ]= mot_val[3 ]= mot_val[1+2*stride]= mot_val[3+2*stride]= my;
778 if(USES_LIST(mb_type, 1)){
779 int16_t *mot_val= h263_pred_motion(s, 0, 1, &mx, &my);
780 s->mv_dir |= MV_DIR_BACKWARD;
782 mx = h263_decode_motion(s, mx, 1);
783 my = h263_decode_motion(s, my, 1);
787 mot_val[0 ]= mot_val[2 ]= mot_val[0+2*stride]= mot_val[2+2*stride]= mx;
788 mot_val[1 ]= mot_val[3 ]= mot_val[1+2*stride]= mot_val[3+2*stride]= my;
792 s->current_picture.f.mb_type[xy] = mb_type;
793 } else { /* I-Frame */
795 cbpc = get_vlc2(&s->gb, ff_h263_intra_MCBPC_vlc.table, INTRA_MCBPC_VLC_BITS, 2);
797 av_log(s->avctx, AV_LOG_ERROR, "I cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
802 s->dsp.clear_blocks(s->block[0]);
807 s->current_picture.f.mb_type[xy] = MB_TYPE_INTRA;
809 s->ac_pred = get_bits1(&s->gb);
811 s->current_picture.f.mb_type[xy] = MB_TYPE_INTRA | MB_TYPE_ACPRED;
813 s->h263_aic_dir = get_bits1(&s->gb);
818 if(s->pb_frame && get_bits1(&s->gb))
819 pb_mv_count = h263_get_modb(&s->gb, s->pb_frame, &cbpb);
820 cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
822 av_log(s->avctx, AV_LOG_ERROR, "I cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
825 cbp = (cbpc & 3) | (cbpy << 2);
827 h263_decode_dquant(s);
830 pb_mv_count += !!s->pb_frame;
833 while(pb_mv_count--){
834 h263_decode_motion(s, 0, 1);
835 h263_decode_motion(s, 0, 1);
838 /* decode each block */
839 for (i = 0; i < 6; i++) {
840 if (h263_decode_block(s, block[i], i, cbp&32) < 0)
845 if(s->pb_frame && h263_skip_b_part(s, cbpb) < 0)
847 if(s->obmc && !s->mb_intra){
848 if(s->pict_type == AV_PICTURE_TYPE_P && s->mb_x+1<s->mb_width && s->mb_num_left != 1)
853 /* per-MB end of slice check */
855 int v= show_bits(&s->gb, 16);
857 if(get_bits_count(&s->gb) + 16 > s->gb.size_in_bits){
858 v>>= get_bits_count(&s->gb) + 16 - s->gb.size_in_bits;
868 /* most is hardcoded. should extend to handle all h263 streams */
869 int h263_decode_picture_header(MpegEncContext *s)
871 int format, width, height, i;
874 align_get_bits(&s->gb);
876 startcode= get_bits(&s->gb, 22-8);
878 for(i= get_bits_left(&s->gb); i>24; i-=8) {
879 startcode = ((startcode << 8) | get_bits(&s->gb, 8)) & 0x003FFFFF;
881 if(startcode == 0x20)
885 if (startcode != 0x20) {
886 av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
889 /* temporal reference */
890 i = get_bits(&s->gb, 8); /* picture timestamp */
891 if( (s->picture_number&~0xFF)+i < s->picture_number)
893 s->current_picture_ptr->f.pts =
894 s->picture_number= (s->picture_number&~0xFF) + i;
896 /* PTYPE starts here */
897 if (get_bits1(&s->gb) != 1) {
899 av_log(s->avctx, AV_LOG_ERROR, "Bad marker\n");
902 if (get_bits1(&s->gb) != 0) {
903 av_log(s->avctx, AV_LOG_ERROR, "Bad H263 id\n");
904 return -1; /* h263 id */
906 skip_bits1(&s->gb); /* split screen off */
907 skip_bits1(&s->gb); /* camera off */
908 skip_bits1(&s->gb); /* freeze picture release off */
910 format = get_bits(&s->gb, 3);
915 7 extended PTYPE (PLUSPTYPE)
918 if (format != 7 && format != 6) {
921 width = h263_format[format][0];
922 height = h263_format[format][1];
926 s->pict_type = AV_PICTURE_TYPE_I + get_bits1(&s->gb);
928 s->h263_long_vectors = get_bits1(&s->gb);
930 if (get_bits1(&s->gb) != 0) {
931 av_log(s->avctx, AV_LOG_ERROR, "H263 SAC not supported\n");
932 return -1; /* SAC: off */
934 s->obmc= get_bits1(&s->gb); /* Advanced prediction mode */
935 s->unrestricted_mv = s->h263_long_vectors || s->obmc;
937 s->pb_frame = get_bits1(&s->gb);
938 s->chroma_qscale= s->qscale = get_bits(&s->gb, 5);
939 skip_bits1(&s->gb); /* Continuous Presence Multipoint mode: off */
943 s->avctx->sample_aspect_ratio= (AVRational){12,11};
944 s->avctx->time_base= (AVRational){1001, 30000};
950 ufep = get_bits(&s->gb, 3); /* Update Full Extended PTYPE */
952 /* ufep other than 0 and 1 are reserved */
955 format = get_bits(&s->gb, 3);
956 av_dlog(s->avctx, "ufep=1, format: %d\n", format);
957 s->custom_pcf= get_bits1(&s->gb);
958 s->umvplus = get_bits1(&s->gb); /* Unrestricted Motion Vector */
959 if (get_bits1(&s->gb) != 0) {
960 av_log(s->avctx, AV_LOG_ERROR, "Syntax-based Arithmetic Coding (SAC) not supported\n");
962 s->obmc= get_bits1(&s->gb); /* Advanced prediction mode */
963 s->h263_aic = get_bits1(&s->gb); /* Advanced Intra Coding (AIC) */
964 s->loop_filter= get_bits1(&s->gb);
965 s->unrestricted_mv = s->umvplus || s->obmc || s->loop_filter;
967 s->h263_slice_structured= get_bits1(&s->gb);
968 if (get_bits1(&s->gb) != 0) {
969 av_log(s->avctx, AV_LOG_ERROR, "Reference Picture Selection not supported\n");
971 if (get_bits1(&s->gb) != 0) {
972 av_log(s->avctx, AV_LOG_ERROR, "Independent Segment Decoding not supported\n");
974 s->alt_inter_vlc= get_bits1(&s->gb);
975 s->modified_quant= get_bits1(&s->gb);
976 if(s->modified_quant)
977 s->chroma_qscale_table= ff_h263_chroma_qscale_table;
979 skip_bits(&s->gb, 1); /* Prevent start code emulation */
981 skip_bits(&s->gb, 3); /* Reserved */
982 } else if (ufep != 0) {
983 av_log(s->avctx, AV_LOG_ERROR, "Bad UFEP type (%d)\n", ufep);
988 s->pict_type = get_bits(&s->gb, 3);
989 switch(s->pict_type){
990 case 0: s->pict_type= AV_PICTURE_TYPE_I;break;
991 case 1: s->pict_type= AV_PICTURE_TYPE_P;break;
992 case 2: s->pict_type= AV_PICTURE_TYPE_P;s->pb_frame = 3;break;
993 case 3: s->pict_type= AV_PICTURE_TYPE_B;break;
994 case 7: s->pict_type= AV_PICTURE_TYPE_I;break; //ZYGO
998 skip_bits(&s->gb, 2);
999 s->no_rounding = get_bits1(&s->gb);
1000 skip_bits(&s->gb, 4);
1002 /* Get the picture dimensions */
1005 /* Custom Picture Format (CPFMT) */
1006 s->aspect_ratio_info = get_bits(&s->gb, 4);
1007 av_dlog(s->avctx, "aspect: %d\n", s->aspect_ratio_info);
1012 3 - 10:11 (525-type 4:3)
1013 4 - 16:11 (CIF 16:9)
1014 5 - 40:33 (525-type 16:9)
1017 width = (get_bits(&s->gb, 9) + 1) * 4;
1019 height = get_bits(&s->gb, 9) * 4;
1020 av_dlog(s->avctx, "\nH.263+ Custom picture: %dx%d\n",width,height);
1021 if (s->aspect_ratio_info == FF_ASPECT_EXTENDED) {
1022 /* aspected dimensions */
1023 s->avctx->sample_aspect_ratio.num= get_bits(&s->gb, 8);
1024 s->avctx->sample_aspect_ratio.den= get_bits(&s->gb, 8);
1026 s->avctx->sample_aspect_ratio= ff_h263_pixel_aspect[s->aspect_ratio_info];
1029 width = h263_format[format][0];
1030 height = h263_format[format][1];
1031 s->avctx->sample_aspect_ratio= (AVRational){12,11};
1033 if ((width == 0) || (height == 0))
1040 s->avctx->time_base.den= 1800000;
1041 s->avctx->time_base.num= 1000 + get_bits1(&s->gb);
1042 s->avctx->time_base.num*= get_bits(&s->gb, 7);
1043 if(s->avctx->time_base.num == 0){
1044 av_log(s, AV_LOG_ERROR, "zero framerate\n");
1047 gcd= av_gcd(s->avctx->time_base.den, s->avctx->time_base.num);
1048 s->avctx->time_base.den /= gcd;
1049 s->avctx->time_base.num /= gcd;
1051 s->avctx->time_base= (AVRational){1001, 30000};
1056 skip_bits(&s->gb, 2); //extended Temporal reference
1061 if(get_bits1(&s->gb)==0) /* Unlimited Unrestricted Motion Vectors Indicator (UUI) */
1064 if(s->h263_slice_structured){
1065 if (get_bits1(&s->gb) != 0) {
1066 av_log(s->avctx, AV_LOG_ERROR, "rectangular slices not supported\n");
1068 if (get_bits1(&s->gb) != 0) {
1069 av_log(s->avctx, AV_LOG_ERROR, "unordered slices not supported\n");
1074 s->qscale = get_bits(&s->gb, 5);
1077 s->mb_width = (s->width + 15) / 16;
1078 s->mb_height = (s->height + 15) / 16;
1079 s->mb_num = s->mb_width * s->mb_height;
1082 skip_bits(&s->gb, 3); /* Temporal reference for B-pictures */
1084 skip_bits(&s->gb, 2); //extended Temporal reference
1085 skip_bits(&s->gb, 2); /* Quantization information for B-pictures */
1089 while (get_bits1(&s->gb) != 0) {
1090 skip_bits(&s->gb, 8);
1093 if(s->h263_slice_structured){
1094 if (get_bits1(&s->gb) != 1) {
1095 av_log(s->avctx, AV_LOG_ERROR, "SEPB1 marker missing\n");
1099 ff_h263_decode_mba(s);
1101 if (get_bits1(&s->gb) != 1) {
1102 av_log(s->avctx, AV_LOG_ERROR, "SEPB2 marker missing\n");
1109 s->y_dc_scale_table=
1110 s->c_dc_scale_table= ff_aic_dc_scale_table;
1112 s->y_dc_scale_table=
1113 s->c_dc_scale_table= ff_mpeg1_dc_scale_table;
1116 ff_h263_show_pict_info(s);
1117 if (s->pict_type == AV_PICTURE_TYPE_I && s->codec_tag == AV_RL32("ZYGO")){
1119 for(i=0; i<85; i++) av_log(s->avctx, AV_LOG_DEBUG, "%d", get_bits1(&s->gb));
1120 av_log(s->avctx, AV_LOG_DEBUG, "\n");
1121 for(i=0; i<13; i++){
1123 int v= get_bits(&s->gb, 8);
1124 v |= get_sbits(&s->gb, 8)<<8;
1125 av_log(s->avctx, AV_LOG_DEBUG, " %5d", v);
1127 av_log(s->avctx, AV_LOG_DEBUG, "\n");
1129 for(i=0; i<50; i++) av_log(s->avctx, AV_LOG_DEBUG, "%d", get_bits1(&s->gb));