2 * ITU H.263 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
33 #include "libavutil/attributes.h"
34 #include "libavutil/imgutils.h"
35 #include "libavutil/internal.h"
36 #include "libavutil/mathematics.h"
38 #include "mpegvideo.h"
43 #include "mpegutils.h"
47 #include "mpeg4video.h"
48 #include "mpegvideodata.h"
50 // The defines below define the number of bits that are read at once for
51 // reading vlc values. Changing these may improve speed and data cache needs
52 // be aware though that decreasing them may need the number of stages that is
53 // passed to get_vlc* to be increased.
55 #define H263_MBTYPE_B_VLC_BITS 6
56 #define CBPC_B_VLC_BITS 3
58 static const int h263_mb_type_b_map[15]= {
59 MB_TYPE_DIRECT2 | MB_TYPE_L0L1,
60 MB_TYPE_DIRECT2 | MB_TYPE_L0L1 | MB_TYPE_CBP,
61 MB_TYPE_DIRECT2 | MB_TYPE_L0L1 | MB_TYPE_CBP | MB_TYPE_QUANT,
62 MB_TYPE_L0 | MB_TYPE_16x16,
63 MB_TYPE_L0 | MB_TYPE_CBP | MB_TYPE_16x16,
64 MB_TYPE_L0 | MB_TYPE_CBP | MB_TYPE_QUANT | MB_TYPE_16x16,
65 MB_TYPE_L1 | MB_TYPE_16x16,
66 MB_TYPE_L1 | MB_TYPE_CBP | MB_TYPE_16x16,
67 MB_TYPE_L1 | MB_TYPE_CBP | MB_TYPE_QUANT | MB_TYPE_16x16,
68 MB_TYPE_L0L1 | MB_TYPE_16x16,
69 MB_TYPE_L0L1 | MB_TYPE_CBP | MB_TYPE_16x16,
70 MB_TYPE_L0L1 | MB_TYPE_CBP | MB_TYPE_QUANT | MB_TYPE_16x16,
72 MB_TYPE_INTRA4x4 | MB_TYPE_CBP,
73 MB_TYPE_INTRA4x4 | MB_TYPE_CBP | MB_TYPE_QUANT,
76 void ff_h263_show_pict_info(MpegEncContext *s){
77 if(s->avctx->debug&FF_DEBUG_PICT_INFO){
78 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",
79 s->qscale, av_get_picture_type_char(s->pict_type),
80 s->gb.size_in_bits, 1-s->no_rounding,
82 s->umvplus ? " UMV" : "",
83 s->h263_long_vectors ? " LONG" : "",
84 s->h263_plus ? " +" : "",
85 s->h263_aic ? " AIC" : "",
86 s->alt_inter_vlc ? " AIV" : "",
87 s->modified_quant ? " MQ" : "",
88 s->loop_filter ? " LOOP" : "",
89 s->h263_slice_structured ? " SS" : "",
90 s->avctx->framerate.num, s->avctx->framerate.den
95 /***********************************************/
98 VLC ff_h263_intra_MCBPC_vlc;
99 VLC ff_h263_inter_MCBPC_vlc;
100 VLC ff_h263_cbpy_vlc;
102 static VLC h263_mbtype_b_vlc;
103 static VLC cbpc_b_vlc;
107 /* XXX: find a better solution to handle static init */
108 av_cold void ff_h263_decode_init_vlc(void)
110 static volatile int done = 0;
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,
123 &ff_mvtab[0][1], 2, 1,
124 &ff_mvtab[0][0], 2, 1, 538);
125 ff_rl_init(&ff_h263_rl_inter, ff_h263_static_rl_table_store[0]);
126 ff_rl_init(&ff_rl_intra_aic, ff_h263_static_rl_table_store[1]);
127 INIT_VLC_RL(ff_h263_rl_inter, 554);
128 INIT_VLC_RL(ff_rl_intra_aic, 554);
129 INIT_VLC_STATIC(&h263_mbtype_b_vlc, H263_MBTYPE_B_VLC_BITS, 15,
130 &ff_h263_mbtype_b_tab[0][1], 2, 1,
131 &ff_h263_mbtype_b_tab[0][0], 2, 1, 80);
132 INIT_VLC_STATIC(&cbpc_b_vlc, CBPC_B_VLC_BITS, 4,
133 &ff_cbpc_b_tab[0][1], 2, 1,
134 &ff_cbpc_b_tab[0][0], 2, 1, 8);
139 int ff_h263_decode_mba(MpegEncContext *s)
143 for (i = 0; i < 6; i++)
144 if (s->mb_num - 1 <= ff_mba_max[i])
146 mb_pos = get_bits(&s->gb, ff_mba_length[i]);
147 s->mb_x = mb_pos % s->mb_width;
148 s->mb_y = mb_pos / s->mb_width;
154 * Decode the group of blocks header or slice header.
155 * @return <0 if an error occurred
157 static int h263_decode_gob_header(MpegEncContext *s)
159 unsigned int val, gob_number;
162 /* Check for GOB Start Code */
163 val = show_bits(&s->gb, 16);
167 /* We have a GBSC probably with GSTUFF */
168 skip_bits(&s->gb, 16); /* Drop the zeros */
169 left= get_bits_left(&s->gb);
170 left = FFMIN(left, 32);
171 //MN: we must check the bits left or we might end in an infinite loop (or segfault)
172 for(;left>13; left--){
173 if(get_bits1(&s->gb)) break; /* Seek the '1' bit */
178 if(s->h263_slice_structured){
179 if(check_marker(s->avctx, &s->gb, "before MBA")==0)
182 ff_h263_decode_mba(s);
185 if(check_marker(s->avctx, &s->gb, "after MBA")==0)
188 s->qscale = get_bits(&s->gb, 5); /* SQUANT */
189 if(check_marker(s->avctx, &s->gb, "after SQUANT")==0)
191 skip_bits(&s->gb, 2); /* GFID */
193 gob_number = get_bits(&s->gb, 5); /* GN */
195 s->mb_y= s->gob_index* gob_number;
196 skip_bits(&s->gb, 2); /* GFID */
197 s->qscale = get_bits(&s->gb, 5); /* GQUANT */
200 if(s->mb_y >= s->mb_height)
210 * Decode the group of blocks / video packet header.
211 * @return bit position of the resync_marker, or <0 if none was found
213 int ff_h263_resync(MpegEncContext *s){
216 if(s->codec_id==AV_CODEC_ID_MPEG4){
218 align_get_bits(&s->gb);
221 if(show_bits(&s->gb, 16)==0){
222 pos= get_bits_count(&s->gb);
223 if(CONFIG_MPEG4_DECODER && s->codec_id==AV_CODEC_ID_MPEG4)
224 ret= ff_mpeg4_decode_video_packet_header(s->avctx->priv_data);
226 ret= h263_decode_gob_header(s);
230 //OK, it's not where it is supposed to be ...
231 s->gb= s->last_resync_gb;
232 align_get_bits(&s->gb);
233 left= get_bits_left(&s->gb);
235 for(;left>16+1+5+5; left-=8){
236 if(show_bits(&s->gb, 16)==0){
237 GetBitContext bak= s->gb;
239 pos= get_bits_count(&s->gb);
240 if(CONFIG_MPEG4_DECODER && s->codec_id==AV_CODEC_ID_MPEG4)
241 ret= ff_mpeg4_decode_video_packet_header(s->avctx->priv_data);
243 ret= h263_decode_gob_header(s);
249 skip_bits(&s->gb, 8);
255 int ff_h263_decode_motion(MpegEncContext * s, int pred, int f_code)
257 int code, val, sign, shift;
258 code = get_vlc2(&s->gb, mv_vlc.table, MV_VLC_BITS, 2);
265 sign = get_bits1(&s->gb);
269 val = (val - 1) << shift;
270 val |= get_bits(&s->gb, shift);
277 /* modulo decoding */
278 if (!s->h263_long_vectors) {
279 val = sign_extend(val, 5 + f_code);
281 /* horrible H.263 long vector mode */
282 if (pred < -31 && val < -63)
284 if (pred > 32 && val > 63)
292 /* Decode RVLC of H.263+ UMV */
293 static int h263p_decode_umotion(MpegEncContext * s, int pred)
297 if (get_bits1(&s->gb)) /* Motion difference = 0 */
300 code = 2 + get_bits1(&s->gb);
302 while (get_bits1(&s->gb))
305 code += get_bits1(&s->gb);
310 code = (sign) ? (pred - code) : (pred + code);
311 ff_tlog(s->avctx,"H.263+ UMV Motion = %d\n", code);
317 * read the next MVs for OBMC. yes this is an ugly hack, feel free to send a patch :)
319 static void preview_obmc(MpegEncContext *s){
320 GetBitContext gb= s->gb;
322 int cbpc, i, pred_x, pred_y, mx, my;
324 const int xy= s->mb_x + 1 + s->mb_y * s->mb_stride;
325 const int stride= s->b8_stride*2;
328 s->block_index[i]+= 2;
330 s->block_index[i]+= 1;
333 av_assert2(s->pict_type == AV_PICTURE_TYPE_P);
336 if (get_bits1(&s->gb)) {
338 mot_val = s->current_picture.motion_val[0][s->block_index[0]];
339 mot_val[0 ]= mot_val[2 ]=
340 mot_val[0+stride]= mot_val[2+stride]= 0;
341 mot_val[1 ]= mot_val[3 ]=
342 mot_val[1+stride]= mot_val[3+stride]= 0;
344 s->current_picture.mb_type[xy] = MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
347 cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
351 s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
353 get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
355 if(s->modified_quant){
356 if(get_bits1(&s->gb)) skip_bits(&s->gb, 1);
357 else skip_bits(&s->gb, 5);
359 skip_bits(&s->gb, 2);
362 if ((cbpc & 16) == 0) {
363 s->current_picture.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
364 /* 16x16 motion prediction */
365 mot_val= ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
367 mx = h263p_decode_umotion(s, pred_x);
369 mx = ff_h263_decode_motion(s, pred_x, 1);
372 my = h263p_decode_umotion(s, pred_y);
374 my = ff_h263_decode_motion(s, pred_y, 1);
376 mot_val[0 ]= mot_val[2 ]=
377 mot_val[0+stride]= mot_val[2+stride]= mx;
378 mot_val[1 ]= mot_val[3 ]=
379 mot_val[1+stride]= mot_val[3+stride]= my;
381 s->current_picture.mb_type[xy] = MB_TYPE_8x8 | MB_TYPE_L0;
383 mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
385 mx = h263p_decode_umotion(s, pred_x);
387 mx = ff_h263_decode_motion(s, pred_x, 1);
390 my = h263p_decode_umotion(s, pred_y);
392 my = ff_h263_decode_motion(s, pred_y, 1);
393 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
394 skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
403 s->block_index[i]-= 2;
405 s->block_index[i]-= 1;
411 static void h263_decode_dquant(MpegEncContext *s){
412 static const int8_t quant_tab[4] = { -1, -2, 1, 2 };
414 if(s->modified_quant){
415 if(get_bits1(&s->gb))
416 s->qscale= ff_modified_quant_tab[get_bits1(&s->gb)][ s->qscale ];
418 s->qscale= get_bits(&s->gb, 5);
420 s->qscale += quant_tab[get_bits(&s->gb, 2)];
421 ff_set_qscale(s, s->qscale);
424 static int h263_decode_block(MpegEncContext * s, int16_t * block,
427 int level, i, j, run;
428 RLTable *rl = &ff_h263_rl_inter;
429 const uint8_t *scan_table;
430 GetBitContext gb= s->gb;
432 scan_table = s->intra_scantable.permutated;
433 if (s->h263_aic && s->mb_intra) {
434 rl = &ff_rl_intra_aic;
438 scan_table = s->intra_v_scantable.permutated; /* left */
440 scan_table = s->intra_h_scantable.permutated; /* top */
442 } else if (s->mb_intra) {
444 if (CONFIG_RV10_DECODER && s->codec_id == AV_CODEC_ID_RV10) {
445 if (s->rv10_version == 3 && s->pict_type == AV_PICTURE_TYPE_I) {
447 component = (n <= 3 ? 0 : n - 4 + 1);
448 level = s->last_dc[component];
449 if (s->rv10_first_dc_coded[component]) {
450 diff = ff_rv_decode_dc(s, n);
454 level = level & 0xff; /* handle wrap round */
455 s->last_dc[component] = level;
457 s->rv10_first_dc_coded[component] = 1;
460 level = get_bits(&s->gb, 8);
465 level = get_bits(&s->gb, 8);
466 if((level&0x7F) == 0){
467 av_log(s->avctx, AV_LOG_ERROR, "illegal dc %d at %d %d\n", level, s->mb_x, s->mb_y);
468 if (s->avctx->err_recognition & (AV_EF_BITSTREAM|AV_EF_COMPLIANT))
480 if (s->mb_intra && s->h263_aic)
482 s->block_last_index[n] = i - 1;
487 OPEN_READER(re, &s->gb);
488 i--; // offset by -1 to allow direct indexing of scan_table
490 UPDATE_CACHE(re, &s->gb);
491 GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);
494 CLOSE_READER(re, &s->gb);
495 av_log(s->avctx, AV_LOG_ERROR, "illegal ac vlc code at %dx%d\n", s->mb_x, s->mb_y);
499 if (CONFIG_FLV_DECODER && s->h263_flv > 1) {
500 int is11 = SHOW_UBITS(re, &s->gb, 1);
501 SKIP_CACHE(re, &s->gb, 1);
502 run = SHOW_UBITS(re, &s->gb, 7) + 1;
504 SKIP_COUNTER(re, &s->gb, 1 + 7);
505 UPDATE_CACHE(re, &s->gb);
506 level = SHOW_SBITS(re, &s->gb, 11);
507 SKIP_COUNTER(re, &s->gb, 11);
509 SKIP_CACHE(re, &s->gb, 7);
510 level = SHOW_SBITS(re, &s->gb, 7);
511 SKIP_COUNTER(re, &s->gb, 1 + 7 + 7);
514 run = SHOW_UBITS(re, &s->gb, 7) + 1;
515 SKIP_CACHE(re, &s->gb, 7);
516 level = (int8_t)SHOW_UBITS(re, &s->gb, 8);
517 SKIP_COUNTER(re, &s->gb, 7 + 8);
519 UPDATE_CACHE(re, &s->gb);
520 if (s->codec_id == AV_CODEC_ID_RV10) {
521 /* XXX: should patch encoder too */
522 level = SHOW_SBITS(re, &s->gb, 12);
523 SKIP_COUNTER(re, &s->gb, 12);
525 level = SHOW_UBITS(re, &s->gb, 5);
526 SKIP_CACHE(re, &s->gb, 5);
527 level |= SHOW_SBITS(re, &s->gb, 6)<<5;
528 SKIP_COUNTER(re, &s->gb, 5 + 6);
533 if (SHOW_UBITS(re, &s->gb, 1))
535 SKIP_COUNTER(re, &s->gb, 1);
539 CLOSE_READER(re, &s->gb);
540 // redo update without last flag, revert -1 offset
541 i = i - run + ((run-1)&63) + 1;
543 // only last marker, no overrun
544 block[scan_table[i]] = level;
547 if(s->alt_inter_vlc && rl == &ff_h263_rl_inter && !s->mb_intra){
548 //Looks like a hack but no, it's the way it is supposed to work ...
549 rl = &ff_rl_intra_aic;
552 s->bdsp.clear_block(block);
555 av_log(s->avctx, AV_LOG_ERROR, "run overflow at %dx%d i:%d\n", s->mb_x, s->mb_y, s->mb_intra);
563 if (s->mb_intra && s->h263_aic) {
564 ff_h263_pred_acdc(s, block, n);
567 s->block_last_index[n] = i;
571 static int h263_skip_b_part(MpegEncContext *s, int cbp)
573 LOCAL_ALIGNED_16(int16_t, dblock, [64]);
577 /* we have to set s->mb_intra to zero to decode B-part of PB-frame correctly
578 * but real value should be restored in order to be used later (in OBMC condition)
581 memcpy(bli, s->block_last_index, sizeof(bli));
583 for (i = 0; i < 6; i++) {
584 if (h263_decode_block(s, dblock, i, cbp&32) < 0)
589 memcpy(s->block_last_index, bli, sizeof(bli));
593 static int h263_get_modb(GetBitContext *gb, int pb_frame, int *cbpb)
597 if (pb_frame < 3) { // h.263 Annex G and i263 PB-frame
599 if (pb_frame == 2 && c)
601 } else { // h.263 Annex M improved PB-frame
602 mv = get_unary(gb, 0, 4) + 1;
607 *cbpb = get_bits(gb, 6);
611 #define tab_size ((signed)FF_ARRAY_ELEMS(s->direct_scale_mv[0]))
612 #define tab_bias (tab_size / 2)
613 static inline void set_one_direct_mv(MpegEncContext *s, Picture *p, int i)
615 int xy = s->block_index[i];
616 uint16_t time_pp = s->pp_time;
617 uint16_t time_pb = s->pb_time;
620 p_mx = p->motion_val[0][xy][0];
621 if ((unsigned)(p_mx + tab_bias) < tab_size) {
622 s->mv[0][i][0] = s->direct_scale_mv[0][p_mx + tab_bias];
623 s->mv[1][i][0] = s->direct_scale_mv[1][p_mx + tab_bias];
625 s->mv[0][i][0] = p_mx * time_pb / time_pp;
626 s->mv[1][i][0] = p_mx * (time_pb - time_pp) / time_pp;
628 p_my = p->motion_val[0][xy][1];
629 if ((unsigned)(p_my + tab_bias) < tab_size) {
630 s->mv[0][i][1] = s->direct_scale_mv[0][p_my + tab_bias];
631 s->mv[1][i][1] = s->direct_scale_mv[1][p_my + tab_bias];
633 s->mv[0][i][1] = p_my * time_pb / time_pp;
634 s->mv[1][i][1] = p_my * (time_pb - time_pp) / time_pp;
639 * @return the mb_type
641 static int set_direct_mv(MpegEncContext *s)
643 const int mb_index = s->mb_x + s->mb_y * s->mb_stride;
644 Picture *p = &s->next_picture;
645 int colocated_mb_type = p->mb_type[mb_index];
648 if (s->codec_tag == AV_RL32("U263") && p->f->pict_type == AV_PICTURE_TYPE_I) {
649 p = &s->last_picture;
650 colocated_mb_type = p->mb_type[mb_index];
653 if (IS_8X8(colocated_mb_type)) {
654 s->mv_type = MV_TYPE_8X8;
655 for (i = 0; i < 4; i++)
656 set_one_direct_mv(s, p, i);
657 return MB_TYPE_DIRECT2 | MB_TYPE_8x8 | MB_TYPE_L0L1;
659 set_one_direct_mv(s, p, 0);
662 s->mv[0][3][0] = s->mv[0][0][0];
665 s->mv[0][3][1] = s->mv[0][0][1];
668 s->mv[1][3][0] = s->mv[1][0][0];
671 s->mv[1][3][1] = s->mv[1][0][1];
672 s->mv_type = MV_TYPE_8X8;
673 // Note see prev line
674 return MB_TYPE_DIRECT2 | MB_TYPE_16x16 | MB_TYPE_L0L1;
678 int ff_h263_decode_mb(MpegEncContext *s,
679 int16_t block[6][64])
681 int cbpc, cbpy, i, cbp, pred_x, pred_y, mx, my, dquant;
683 const int xy= s->mb_x + s->mb_y * s->mb_stride;
684 int cbpb = 0, pb_mv_count = 0;
686 av_assert2(!s->h263_pred);
688 if (s->pict_type == AV_PICTURE_TYPE_P) {
690 if (get_bits1(&s->gb)) {
694 s->block_last_index[i] = -1;
695 s->mv_dir = MV_DIR_FORWARD;
696 s->mv_type = MV_TYPE_16X16;
697 s->current_picture.mb_type[xy] = MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
700 s->mb_skipped = !(s->obmc | s->loop_filter);
703 cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
705 av_log(s->avctx, AV_LOG_ERROR, "cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
710 s->bdsp.clear_blocks(s->block[0]);
713 s->mb_intra = ((cbpc & 4) != 0);
714 if (s->mb_intra) goto intra;
716 if(s->pb_frame && get_bits1(&s->gb))
717 pb_mv_count = h263_get_modb(&s->gb, s->pb_frame, &cbpb);
718 cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
720 if(s->alt_inter_vlc==0 || (cbpc & 3)!=3)
723 cbp = (cbpc & 3) | (cbpy << 2);
725 h263_decode_dquant(s);
728 s->mv_dir = MV_DIR_FORWARD;
729 if ((cbpc & 16) == 0) {
730 s->current_picture.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
731 /* 16x16 motion prediction */
732 s->mv_type = MV_TYPE_16X16;
733 ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
735 mx = h263p_decode_umotion(s, pred_x);
737 mx = ff_h263_decode_motion(s, pred_x, 1);
743 my = h263p_decode_umotion(s, pred_y);
745 my = ff_h263_decode_motion(s, pred_y, 1);
752 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
753 skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
755 s->current_picture.mb_type[xy] = MB_TYPE_8x8 | MB_TYPE_L0;
756 s->mv_type = MV_TYPE_8X8;
758 mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
760 mx = h263p_decode_umotion(s, pred_x);
762 mx = ff_h263_decode_motion(s, pred_x, 1);
767 my = h263p_decode_umotion(s, pred_y);
769 my = ff_h263_decode_motion(s, pred_y, 1);
774 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
775 skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
780 } else if(s->pict_type==AV_PICTURE_TYPE_B) {
782 const int stride= s->b8_stride;
783 int16_t *mot_val0 = s->current_picture.motion_val[0][2 * (s->mb_x + s->mb_y * stride)];
784 int16_t *mot_val1 = s->current_picture.motion_val[1][2 * (s->mb_x + s->mb_y * stride)];
785 // const int mv_xy= s->mb_x + 1 + s->mb_y * s->mb_stride;
788 mot_val0[0 ]= mot_val0[2 ]= mot_val0[0+2*stride]= mot_val0[2+2*stride]=
789 mot_val0[1 ]= mot_val0[3 ]= mot_val0[1+2*stride]= mot_val0[3+2*stride]=
790 mot_val1[0 ]= mot_val1[2 ]= mot_val1[0+2*stride]= mot_val1[2+2*stride]=
791 mot_val1[1 ]= mot_val1[3 ]= mot_val1[1+2*stride]= mot_val1[3+2*stride]= 0;
794 mb_type= get_vlc2(&s->gb, h263_mbtype_b_vlc.table, H263_MBTYPE_B_VLC_BITS, 2);
796 av_log(s->avctx, AV_LOG_ERROR, "b mb_type damaged at %d %d\n", s->mb_x, s->mb_y);
800 mb_type= h263_mb_type_b_map[ mb_type ];
803 s->mb_intra = IS_INTRA(mb_type);
804 if(HAS_CBP(mb_type)){
805 s->bdsp.clear_blocks(s->block[0]);
806 cbpc = get_vlc2(&s->gb, cbpc_b_vlc.table, CBPC_B_VLC_BITS, 1);
808 dquant = IS_QUANT(mb_type);
812 cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
815 av_log(s->avctx, AV_LOG_ERROR, "b cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
819 if(s->alt_inter_vlc==0 || (cbpc & 3)!=3)
822 cbp = (cbpc & 3) | (cbpy << 2);
826 av_assert2(!s->mb_intra);
828 if(IS_QUANT(mb_type)){
829 h263_decode_dquant(s);
832 if(IS_DIRECT(mb_type)){
833 s->mv_dir = MV_DIR_FORWARD | MV_DIR_BACKWARD | MV_DIRECT;
834 mb_type |= set_direct_mv(s);
837 s->mv_type= MV_TYPE_16X16;
840 if(USES_LIST(mb_type, 0)){
841 int16_t *mot_val= ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
842 s->mv_dir = MV_DIR_FORWARD;
845 mx = h263p_decode_umotion(s, pred_x);
847 mx = ff_h263_decode_motion(s, pred_x, 1);
852 my = h263p_decode_umotion(s, pred_y);
854 my = ff_h263_decode_motion(s, pred_y, 1);
858 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
859 skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
863 mot_val[0 ]= mot_val[2 ]= mot_val[0+2*stride]= mot_val[2+2*stride]= mx;
864 mot_val[1 ]= mot_val[3 ]= mot_val[1+2*stride]= mot_val[3+2*stride]= my;
867 if(USES_LIST(mb_type, 1)){
868 int16_t *mot_val= ff_h263_pred_motion(s, 0, 1, &pred_x, &pred_y);
869 s->mv_dir |= MV_DIR_BACKWARD;
872 mx = h263p_decode_umotion(s, pred_x);
874 mx = ff_h263_decode_motion(s, pred_x, 1);
879 my = h263p_decode_umotion(s, pred_y);
881 my = ff_h263_decode_motion(s, pred_y, 1);
885 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
886 skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
890 mot_val[0 ]= mot_val[2 ]= mot_val[0+2*stride]= mot_val[2+2*stride]= mx;
891 mot_val[1 ]= mot_val[3 ]= mot_val[1+2*stride]= mot_val[3+2*stride]= my;
895 s->current_picture.mb_type[xy] = mb_type;
896 } else { /* I-Frame */
898 cbpc = get_vlc2(&s->gb, ff_h263_intra_MCBPC_vlc.table, INTRA_MCBPC_VLC_BITS, 2);
900 av_log(s->avctx, AV_LOG_ERROR, "I cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
905 s->bdsp.clear_blocks(s->block[0]);
910 s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
912 s->ac_pred = get_bits1(&s->gb);
914 s->current_picture.mb_type[xy] = MB_TYPE_INTRA | MB_TYPE_ACPRED;
916 s->h263_aic_dir = get_bits1(&s->gb);
921 if(s->pb_frame && get_bits1(&s->gb))
922 pb_mv_count = h263_get_modb(&s->gb, s->pb_frame, &cbpb);
923 cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
925 av_log(s->avctx, AV_LOG_ERROR, "I cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
928 cbp = (cbpc & 3) | (cbpy << 2);
930 h263_decode_dquant(s);
933 pb_mv_count += !!s->pb_frame;
936 while(pb_mv_count--){
937 ff_h263_decode_motion(s, 0, 1);
938 ff_h263_decode_motion(s, 0, 1);
941 /* decode each block */
942 for (i = 0; i < 6; i++) {
943 if (h263_decode_block(s, block[i], i, cbp&32) < 0)
948 if(s->pb_frame && h263_skip_b_part(s, cbpb) < 0)
950 if(s->obmc && !s->mb_intra){
951 if(s->pict_type == AV_PICTURE_TYPE_P && s->mb_x+1<s->mb_width && s->mb_num_left != 1)
956 /* per-MB end of slice check */
958 int v= show_bits(&s->gb, 16);
960 if (get_bits_left(&s->gb) < 16) {
961 v >>= 16 - get_bits_left(&s->gb);
971 /* Most is hardcoded; should extend to handle all H.263 streams. */
972 int ff_h263_decode_picture_header(MpegEncContext *s)
974 int format, width, height, i, ret;
977 align_get_bits(&s->gb);
979 if (show_bits(&s->gb, 2) == 2 && s->avctx->frame_number == 0) {
980 av_log(s->avctx, AV_LOG_WARNING, "Header looks like RTP instead of H.263\n");
983 startcode= get_bits(&s->gb, 22-8);
985 for(i= get_bits_left(&s->gb); i>24; i-=8) {
986 startcode = ((startcode << 8) | get_bits(&s->gb, 8)) & 0x003FFFFF;
988 if(startcode == 0x20)
992 if (startcode != 0x20) {
993 av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
996 /* temporal reference */
997 i = get_bits(&s->gb, 8); /* picture timestamp */
999 i -= (i - (s->picture_number & 0xFF) + 128) & ~0xFF;
1001 s->picture_number= (s->picture_number&~0xFF) + i;
1003 /* PTYPE starts here */
1004 if (check_marker(s->avctx, &s->gb, "in PTYPE") != 1) {
1007 if (get_bits1(&s->gb) != 0) {
1008 av_log(s->avctx, AV_LOG_ERROR, "Bad H.263 id\n");
1009 return -1; /* H.263 id */
1011 skip_bits1(&s->gb); /* split screen off */
1012 skip_bits1(&s->gb); /* camera off */
1013 skip_bits1(&s->gb); /* freeze picture release off */
1015 format = get_bits(&s->gb, 3);
1020 7 extended PTYPE (PLUSPTYPE)
1023 if (format != 7 && format != 6) {
1026 width = ff_h263_format[format][0];
1027 height = ff_h263_format[format][1];
1031 s->pict_type = AV_PICTURE_TYPE_I + get_bits1(&s->gb);
1033 s->h263_long_vectors = get_bits1(&s->gb);
1035 if (get_bits1(&s->gb) != 0) {
1036 av_log(s->avctx, AV_LOG_ERROR, "H.263 SAC not supported\n");
1037 return -1; /* SAC: off */
1039 s->obmc= get_bits1(&s->gb); /* Advanced prediction mode */
1040 s->unrestricted_mv = s->h263_long_vectors || s->obmc;
1042 s->pb_frame = get_bits1(&s->gb);
1043 s->chroma_qscale= s->qscale = get_bits(&s->gb, 5);
1044 skip_bits1(&s->gb); /* Continuous Presence Multipoint mode: off */
1048 s->avctx->sample_aspect_ratio= (AVRational){12,11};
1049 s->avctx->framerate = (AVRational){ 30000, 1001 };
1055 ufep = get_bits(&s->gb, 3); /* Update Full Extended PTYPE */
1057 /* ufep other than 0 and 1 are reserved */
1060 format = get_bits(&s->gb, 3);
1061 ff_dlog(s->avctx, "ufep=1, format: %d\n", format);
1062 s->custom_pcf= get_bits1(&s->gb);
1063 s->umvplus = get_bits1(&s->gb); /* Unrestricted Motion Vector */
1064 if (get_bits1(&s->gb) != 0) {
1065 av_log(s->avctx, AV_LOG_ERROR, "Syntax-based Arithmetic Coding (SAC) not supported\n");
1067 s->obmc= get_bits1(&s->gb); /* Advanced prediction mode */
1068 s->h263_aic = get_bits1(&s->gb); /* Advanced Intra Coding (AIC) */
1069 s->loop_filter= get_bits1(&s->gb);
1070 s->unrestricted_mv = s->umvplus || s->obmc || s->loop_filter;
1071 if(s->avctx->lowres)
1074 s->h263_slice_structured= get_bits1(&s->gb);
1075 if (get_bits1(&s->gb) != 0) {
1076 av_log(s->avctx, AV_LOG_ERROR, "Reference Picture Selection not supported\n");
1078 if (get_bits1(&s->gb) != 0) {
1079 av_log(s->avctx, AV_LOG_ERROR, "Independent Segment Decoding not supported\n");
1081 s->alt_inter_vlc= get_bits1(&s->gb);
1082 s->modified_quant= get_bits1(&s->gb);
1083 if(s->modified_quant)
1084 s->chroma_qscale_table= ff_h263_chroma_qscale_table;
1086 skip_bits(&s->gb, 1); /* Prevent start code emulation */
1088 skip_bits(&s->gb, 3); /* Reserved */
1089 } else if (ufep != 0) {
1090 av_log(s->avctx, AV_LOG_ERROR, "Bad UFEP type (%d)\n", ufep);
1095 s->pict_type = get_bits(&s->gb, 3);
1096 switch(s->pict_type){
1097 case 0: s->pict_type= AV_PICTURE_TYPE_I;break;
1098 case 1: s->pict_type= AV_PICTURE_TYPE_P;break;
1099 case 2: s->pict_type= AV_PICTURE_TYPE_P;s->pb_frame = 3;break;
1100 case 3: s->pict_type= AV_PICTURE_TYPE_B;break;
1101 case 7: s->pict_type= AV_PICTURE_TYPE_I;break; //ZYGO
1105 skip_bits(&s->gb, 2);
1106 s->no_rounding = get_bits1(&s->gb);
1107 skip_bits(&s->gb, 4);
1109 /* Get the picture dimensions */
1112 /* Custom Picture Format (CPFMT) */
1113 s->aspect_ratio_info = get_bits(&s->gb, 4);
1114 ff_dlog(s->avctx, "aspect: %d\n", s->aspect_ratio_info);
1119 3 - 10:11 (525-type 4:3)
1120 4 - 16:11 (CIF 16:9)
1121 5 - 40:33 (525-type 16:9)
1124 width = (get_bits(&s->gb, 9) + 1) * 4;
1125 check_marker(s->avctx, &s->gb, "in dimensions");
1126 height = get_bits(&s->gb, 9) * 4;
1127 ff_dlog(s->avctx, "\nH.263+ Custom picture: %dx%d\n",width,height);
1128 if (s->aspect_ratio_info == FF_ASPECT_EXTENDED) {
1129 /* expected dimensions */
1130 s->avctx->sample_aspect_ratio.num= get_bits(&s->gb, 8);
1131 s->avctx->sample_aspect_ratio.den= get_bits(&s->gb, 8);
1133 s->avctx->sample_aspect_ratio= ff_h263_pixel_aspect[s->aspect_ratio_info];
1136 width = ff_h263_format[format][0];
1137 height = ff_h263_format[format][1];
1138 s->avctx->sample_aspect_ratio= (AVRational){12,11};
1140 s->avctx->sample_aspect_ratio.den <<= s->ehc_mode;
1141 if ((width == 0) || (height == 0))
1148 s->avctx->framerate.num = 1800000;
1149 s->avctx->framerate.den = 1000 + get_bits1(&s->gb);
1150 s->avctx->framerate.den *= get_bits(&s->gb, 7);
1151 if(s->avctx->framerate.den == 0){
1152 av_log(s, AV_LOG_ERROR, "zero framerate\n");
1155 gcd= av_gcd(s->avctx->framerate.den, s->avctx->framerate.num);
1156 s->avctx->framerate.den /= gcd;
1157 s->avctx->framerate.num /= gcd;
1159 s->avctx->framerate = (AVRational){ 30000, 1001 };
1164 skip_bits(&s->gb, 2); //extended Temporal reference
1169 if(get_bits1(&s->gb)==0) /* Unlimited Unrestricted Motion Vectors Indicator (UUI) */
1172 if(s->h263_slice_structured){
1173 if (get_bits1(&s->gb) != 0) {
1174 av_log(s->avctx, AV_LOG_ERROR, "rectangular slices not supported\n");
1176 if (get_bits1(&s->gb) != 0) {
1177 av_log(s->avctx, AV_LOG_ERROR, "unordered slices not supported\n");
1180 if (s->pict_type == AV_PICTURE_TYPE_B) {
1181 skip_bits(&s->gb, 4); //ELNUM
1183 skip_bits(&s->gb, 4); // RLNUM
1188 s->qscale = get_bits(&s->gb, 5);
1191 if ((ret = av_image_check_size(s->width, s->height, 0, s)) < 0)
1194 s->mb_width = (s->width + 15) / 16;
1195 s->mb_height = (s->height + 15) / 16;
1196 s->mb_num = s->mb_width * s->mb_height;
1199 skip_bits(&s->gb, 3); /* Temporal reference for B-pictures */
1201 skip_bits(&s->gb, 2); //extended Temporal reference
1202 skip_bits(&s->gb, 2); /* Quantization information for B-pictures */
1205 if (s->pict_type!=AV_PICTURE_TYPE_B) {
1206 s->time = s->picture_number;
1207 s->pp_time = s->time - s->last_non_b_time;
1208 s->last_non_b_time = s->time;
1210 s->time = s->picture_number;
1211 s->pb_time = s->pp_time - (s->last_non_b_time - s->time);
1212 if (s->pp_time <=s->pb_time ||
1213 s->pp_time <= s->pp_time - s->pb_time ||
1218 ff_mpeg4_init_direct_mv(s);
1222 if (skip_1stop_8data_bits(&s->gb) < 0)
1223 return AVERROR_INVALIDDATA;
1225 if(s->h263_slice_structured){
1226 if (check_marker(s->avctx, &s->gb, "SEPB1") != 1) {
1230 ff_h263_decode_mba(s);
1232 if (check_marker(s->avctx, &s->gb, "SEPB2") != 1) {
1238 if (s->pict_type == AV_PICTURE_TYPE_B)
1242 s->y_dc_scale_table=
1243 s->c_dc_scale_table= ff_aic_dc_scale_table;
1245 s->y_dc_scale_table=
1246 s->c_dc_scale_table= ff_mpeg1_dc_scale_table;
1249 ff_h263_show_pict_info(s);
1250 if (s->pict_type == AV_PICTURE_TYPE_I && s->codec_tag == AV_RL32("ZYGO") && get_bits_left(&s->gb) >= 85 + 13*3*16 + 50){
1252 for(i=0; i<85; i++) av_log(s->avctx, AV_LOG_DEBUG, "%d", get_bits1(&s->gb));
1253 av_log(s->avctx, AV_LOG_DEBUG, "\n");
1254 for(i=0; i<13; i++){
1256 int v= get_bits(&s->gb, 8);
1257 v |= get_sbits(&s->gb, 8)<<8;
1258 av_log(s->avctx, AV_LOG_DEBUG, " %5d", v);
1260 av_log(s->avctx, AV_LOG_DEBUG, "\n");
1262 for(i=0; i<50; i++) av_log(s->avctx, AV_LOG_DEBUG, "%d", get_bits1(&s->gb));