b1da22f6559bd2b64151ad544d2461714540dd87
[libav.git] / libavcodec / ituh263dec.c
1 /*
2 * ITU H263 bitstream decoder
3 * Copyright (c) 2000,2001 Fabrice Bellard
4 * H263+ support.
5 * Copyright (c) 2001 Juan J. Sierralta P
6 * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
7 *
8 * This file is part of Libav.
9 *
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.
14 *
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.
19 *
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
23 */
24
25 /**
26 * @file
27 * h263 decoder.
28 */
29
30 #include <limits.h>
31
32 #include "libavutil/attributes.h"
33 #include "libavutil/internal.h"
34 #include "libavutil/mathematics.h"
35 #include "avcodec.h"
36 #include "mpegvideo.h"
37 #include "h263.h"
38 #include "h263data.h"
39 #include "internal.h"
40 #include "mathops.h"
41 #include "mpegutils.h"
42 #include "unary.h"
43 #include "flv.h"
44 #include "rv10.h"
45 #include "mpeg4video.h"
46 #include "mpegvideodata.h"
47
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.
52 #define MV_VLC_BITS 9
53 #define H263_MBTYPE_B_VLC_BITS 6
54 #define CBPC_B_VLC_BITS 3
55
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,
69 0, //stuffing
70 MB_TYPE_INTRA4x4 | MB_TYPE_CBP,
71 MB_TYPE_INTRA4x4 | MB_TYPE_CBP | MB_TYPE_QUANT,
72 };
73
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,
79 s->obmc ? " AP" : "",
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->framerate.num, s->avctx->framerate.den
89 );
90 }
91 }
92
93 /***********************************************/
94 /* decoding */
95
96 VLC ff_h263_intra_MCBPC_vlc;
97 VLC ff_h263_inter_MCBPC_vlc;
98 VLC ff_h263_cbpy_vlc;
99 static VLC mv_vlc;
100 static VLC h263_mbtype_b_vlc;
101 static VLC cbpc_b_vlc;
102
103 /* init vlcs */
104
105 /* XXX: find a better solution to handle static init */
106 av_cold void ff_h263_decode_init_vlc(void)
107 {
108 static int done = 0;
109
110 if (!done) {
111 done = 1;
112
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);
135 }
136 }
137
138 int ff_h263_decode_mba(MpegEncContext *s)
139 {
140 int i, mb_pos;
141
142 for (i = 0; i < 6; i++)
143 if (s->mb_num - 1 <= ff_mba_max[i])
144 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;
148
149 return mb_pos;
150 }
151
152 /**
153 * Decode the group of blocks header or slice header.
154 * @return <0 if an error occurred
155 */
156 static int h263_decode_gob_header(MpegEncContext *s)
157 {
158 unsigned int val, gob_number;
159 int left;
160
161 /* Check for GOB Start Code */
162 val = show_bits(&s->gb, 16);
163 if(val)
164 return -1;
165
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 */
172 }
173 if(left<=13)
174 return -1;
175
176 if(s->h263_slice_structured){
177 if(get_bits1(&s->gb)==0)
178 return -1;
179
180 ff_h263_decode_mba(s);
181
182 if(s->mb_num > 1583)
183 if(get_bits1(&s->gb)==0)
184 return -1;
185
186 s->qscale = get_bits(&s->gb, 5); /* SQUANT */
187 if(get_bits1(&s->gb)==0)
188 return -1;
189 skip_bits(&s->gb, 2); /* GFID */
190 }else{
191 gob_number = get_bits(&s->gb, 5); /* GN */
192 s->mb_x= 0;
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 */
196 }
197
198 if(s->mb_y >= s->mb_height)
199 return -1;
200
201 if(s->qscale==0)
202 return -1;
203
204 return 0;
205 }
206
207 /**
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
212 */
213 const uint8_t *ff_h263_find_resync_marker(const uint8_t *restrict p, const uint8_t * restrict end)
214 {
215 assert(p < end);
216
217 end-=2;
218 p++;
219 for(;p<end; p+=2){
220 if(!*p){
221 if (!p[-1] && p[1]) return p - 1;
222 else if(!p[ 1] && p[2]) return p;
223 }
224 }
225 return end+2;
226 }
227
228 /**
229 * Decode the group of blocks / video packet header.
230 * @return bit position of the resync_marker, or <0 if none was found
231 */
232 int ff_h263_resync(MpegEncContext *s){
233 int left, pos, ret;
234
235 if(s->codec_id==AV_CODEC_ID_MPEG4){
236 skip_bits1(&s->gb);
237 align_get_bits(&s->gb);
238 }
239
240 if(show_bits(&s->gb, 16)==0){
241 pos= get_bits_count(&s->gb);
242 if(CONFIG_MPEG4_DECODER && s->codec_id==AV_CODEC_ID_MPEG4)
243 ret= ff_mpeg4_decode_video_packet_header(s->avctx->priv_data);
244 else
245 ret= h263_decode_gob_header(s);
246 if(ret>=0)
247 return pos;
248 }
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);
253
254 for(;left>16+1+5+5; left-=8){
255 if(show_bits(&s->gb, 16)==0){
256 GetBitContext bak= s->gb;
257
258 pos= get_bits_count(&s->gb);
259 if(CONFIG_MPEG4_DECODER && s->codec_id==AV_CODEC_ID_MPEG4)
260 ret= ff_mpeg4_decode_video_packet_header(s->avctx->priv_data);
261 else
262 ret= h263_decode_gob_header(s);
263 if(ret>=0)
264 return pos;
265
266 s->gb= bak;
267 }
268 skip_bits(&s->gb, 8);
269 }
270
271 return -1;
272 }
273
274 int ff_h263_decode_motion(MpegEncContext * s, int pred, int f_code)
275 {
276 int code, val, sign, shift;
277 code = get_vlc2(&s->gb, mv_vlc.table, MV_VLC_BITS, 2);
278
279 if (code == 0)
280 return pred;
281 if (code < 0)
282 return 0xffff;
283
284 sign = get_bits1(&s->gb);
285 shift = f_code - 1;
286 val = code;
287 if (shift) {
288 val = (val - 1) << shift;
289 val |= get_bits(&s->gb, shift);
290 val++;
291 }
292 if (sign)
293 val = -val;
294 val += pred;
295
296 /* modulo decoding */
297 if (!s->h263_long_vectors) {
298 val = sign_extend(val, 5 + f_code);
299 } else {
300 /* horrible h263 long vector mode */
301 if (pred < -31 && val < -63)
302 val += 64;
303 if (pred > 32 && val > 63)
304 val -= 64;
305
306 }
307 return val;
308 }
309
310
311 /* Decode RVLC of H.263+ UMV */
312 static int h263p_decode_umotion(MpegEncContext * s, int pred)
313 {
314 int code = 0, sign;
315
316 if (get_bits1(&s->gb)) /* Motion difference = 0 */
317 return pred;
318
319 code = 2 + get_bits1(&s->gb);
320
321 while (get_bits1(&s->gb))
322 {
323 code <<= 1;
324 code += get_bits1(&s->gb);
325 }
326 sign = code & 1;
327 code >>= 1;
328
329 code = (sign) ? (pred - code) : (pred + code);
330 ff_dlog(s->avctx,"H.263+ UMV Motion = %d\n", code);
331 return code;
332
333 }
334
335 /**
336 * read the next MVs for OBMC. yes this is a ugly hack, feel free to send a patch :)
337 */
338 static void preview_obmc(MpegEncContext *s){
339 GetBitContext gb= s->gb;
340
341 int cbpc, i, pred_x, pred_y, mx, my;
342 int16_t *mot_val;
343 const int xy= s->mb_x + 1 + s->mb_y * s->mb_stride;
344 const int stride= s->b8_stride*2;
345
346 for(i=0; i<4; i++)
347 s->block_index[i]+= 2;
348 for(i=4; i<6; i++)
349 s->block_index[i]+= 1;
350 s->mb_x++;
351
352 assert(s->pict_type == AV_PICTURE_TYPE_P);
353
354 do{
355 if (get_bits1(&s->gb)) {
356 /* skip mb */
357 mot_val = s->current_picture.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;
362
363 s->current_picture.mb_type[xy] = MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
364 goto end;
365 }
366 cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
367 }while(cbpc == 20);
368
369 if(cbpc & 4){
370 s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
371 }else{
372 get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
373 if (cbpc & 8) {
374 if(s->modified_quant){
375 if(get_bits1(&s->gb)) skip_bits(&s->gb, 1);
376 else skip_bits(&s->gb, 5);
377 }else
378 skip_bits(&s->gb, 2);
379 }
380
381 if ((cbpc & 16) == 0) {
382 s->current_picture.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
383 /* 16x16 motion prediction */
384 mot_val= ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
385 if (s->umvplus)
386 mx = h263p_decode_umotion(s, pred_x);
387 else
388 mx = ff_h263_decode_motion(s, pred_x, 1);
389
390 if (s->umvplus)
391 my = h263p_decode_umotion(s, pred_y);
392 else
393 my = ff_h263_decode_motion(s, pred_y, 1);
394
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;
399 } else {
400 s->current_picture.mb_type[xy] = MB_TYPE_8x8 | MB_TYPE_L0;
401 for(i=0;i<4;i++) {
402 mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
403 if (s->umvplus)
404 mx = h263p_decode_umotion(s, pred_x);
405 else
406 mx = ff_h263_decode_motion(s, pred_x, 1);
407
408 if (s->umvplus)
409 my = h263p_decode_umotion(s, pred_y);
410 else
411 my = ff_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 */
414 mot_val[0] = mx;
415 mot_val[1] = my;
416 }
417 }
418 }
419 end:
420
421 for(i=0; i<4; i++)
422 s->block_index[i]-= 2;
423 for(i=4; i<6; i++)
424 s->block_index[i]-= 1;
425 s->mb_x--;
426
427 s->gb= gb;
428 }
429
430 static void h263_decode_dquant(MpegEncContext *s){
431 static const int8_t quant_tab[4] = { -1, -2, 1, 2 };
432
433 if(s->modified_quant){
434 if(get_bits1(&s->gb))
435 s->qscale= ff_modified_quant_tab[get_bits1(&s->gb)][ s->qscale ];
436 else
437 s->qscale= get_bits(&s->gb, 5);
438 }else
439 s->qscale += quant_tab[get_bits(&s->gb, 2)];
440 ff_set_qscale(s, s->qscale);
441 }
442
443 static int h263_decode_block(MpegEncContext * s, int16_t * block,
444 int n, int coded)
445 {
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;
450
451 scan_table = s->intra_scantable.permutated;
452 if (s->h263_aic && s->mb_intra) {
453 rl = &ff_rl_intra_aic;
454 i = 0;
455 if (s->ac_pred) {
456 if (s->h263_aic_dir)
457 scan_table = s->intra_v_scantable.permutated; /* left */
458 else
459 scan_table = s->intra_h_scantable.permutated; /* top */
460 }
461 } else if (s->mb_intra) {
462 /* DC coef */
463 if (CONFIG_RV10_DECODER && s->codec_id == AV_CODEC_ID_RV10) {
464 if (s->rv10_version == 3 && s->pict_type == AV_PICTURE_TYPE_I) {
465 int component, diff;
466 component = (n <= 3 ? 0 : n - 4 + 1);
467 level = s->last_dc[component];
468 if (s->rv10_first_dc_coded[component]) {
469 diff = ff_rv_decode_dc(s, n);
470 if (diff == 0xffff)
471 return -1;
472 level += diff;
473 level = level & 0xff; /* handle wrap round */
474 s->last_dc[component] = level;
475 } else {
476 s->rv10_first_dc_coded[component] = 1;
477 }
478 } else {
479 level = get_bits(&s->gb, 8);
480 if (level == 255)
481 level = 128;
482 }
483 }else{
484 level = get_bits(&s->gb, 8);
485 if((level&0x7F) == 0){
486 av_log(s->avctx, AV_LOG_ERROR, "illegal dc %d at %d %d\n", level, s->mb_x, s->mb_y);
487 if (s->avctx->err_recognition & AV_EF_BITSTREAM)
488 return -1;
489 }
490 if (level == 255)
491 level = 128;
492 }
493 block[0] = level;
494 i = 1;
495 } else {
496 i = 0;
497 }
498 if (!coded) {
499 if (s->mb_intra && s->h263_aic)
500 goto not_coded;
501 s->block_last_index[n] = i - 1;
502 return 0;
503 }
504 retry:
505 for(;;) {
506 code = get_vlc2(&s->gb, rl->vlc.table, TEX_VLC_BITS, 2);
507 if (code < 0){
508 av_log(s->avctx, AV_LOG_ERROR, "illegal ac vlc code at %dx%d\n", s->mb_x, s->mb_y);
509 return -1;
510 }
511 if (code == rl->n) {
512 /* escape */
513 if (CONFIG_FLV_DECODER && s->h263_flv > 1) {
514 ff_flv2_decode_ac_esc(&s->gb, &level, &run, &last);
515 } else {
516 last = get_bits1(&s->gb);
517 run = get_bits(&s->gb, 6);
518 level = (int8_t)get_bits(&s->gb, 8);
519 if(level == -128){
520 if (s->codec_id == AV_CODEC_ID_RV10) {
521 /* XXX: should patch encoder too */
522 level = get_sbits(&s->gb, 12);
523 }else{
524 level = get_bits(&s->gb, 5);
525 level |= get_sbits(&s->gb, 6)<<5;
526 }
527 }
528 }
529 } else {
530 run = rl->table_run[code];
531 level = rl->table_level[code];
532 last = code >= rl->last;
533 if (get_bits1(&s->gb))
534 level = -level;
535 }
536 i += run;
537 if (i >= 64){
538 if(s->alt_inter_vlc && rl == &ff_h263_rl_inter && !s->mb_intra){
539 //Looks like a hack but no, it's the way it is supposed to work ...
540 rl = &ff_rl_intra_aic;
541 i = 0;
542 s->gb= gb;
543 s->bdsp.clear_block(block);
544 goto retry;
545 }
546 av_log(s->avctx, AV_LOG_ERROR, "run overflow at %dx%d i:%d\n", s->mb_x, s->mb_y, s->mb_intra);
547 return -1;
548 }
549 j = scan_table[i];
550 block[j] = level;
551 if (last)
552 break;
553 i++;
554 }
555 not_coded:
556 if (s->mb_intra && s->h263_aic) {
557 ff_h263_pred_acdc(s, block, n);
558 i = 63;
559 }
560 s->block_last_index[n] = i;
561 return 0;
562 }
563
564 static int h263_skip_b_part(MpegEncContext *s, int cbp)
565 {
566 LOCAL_ALIGNED_16(int16_t, dblock, [64]);
567 int i, mbi;
568
569 /* we have to set s->mb_intra to zero to decode B-part of PB-frame correctly
570 * but real value should be restored in order to be used later (in OBMC condition)
571 */
572 mbi = s->mb_intra;
573 s->mb_intra = 0;
574 for (i = 0; i < 6; i++) {
575 if (h263_decode_block(s, dblock, i, cbp&32) < 0)
576 return -1;
577 cbp+=cbp;
578 }
579 s->mb_intra = mbi;
580 return 0;
581 }
582
583 static int h263_get_modb(GetBitContext *gb, int pb_frame, int *cbpb)
584 {
585 int c, mv = 1;
586
587 if (pb_frame < 3) { // h.263 Annex G and i263 PB-frame
588 c = get_bits1(gb);
589 if (pb_frame == 2 && c)
590 mv = !get_bits1(gb);
591 } else { // h.263 Annex M improved PB-frame
592 mv = get_unary(gb, 0, 4) + 1;
593 c = mv & 1;
594 mv = !!(mv & 2);
595 }
596 if(c)
597 *cbpb = get_bits(gb, 6);
598 return mv;
599 }
600
601 int ff_h263_decode_mb(MpegEncContext *s,
602 int16_t block[6][64])
603 {
604 int cbpc, cbpy, i, cbp, pred_x, pred_y, mx, my, dquant;
605 int16_t *mot_val;
606 const int xy= s->mb_x + s->mb_y * s->mb_stride;
607 int cbpb = 0, pb_mv_count = 0;
608
609 assert(!s->h263_pred);
610
611 if (s->pict_type == AV_PICTURE_TYPE_P) {
612 do{
613 if (get_bits1(&s->gb)) {
614 /* skip mb */
615 s->mb_intra = 0;
616 for(i=0;i<6;i++)
617 s->block_last_index[i] = -1;
618 s->mv_dir = MV_DIR_FORWARD;
619 s->mv_type = MV_TYPE_16X16;
620 s->current_picture.mb_type[xy] = MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
621 s->mv[0][0][0] = 0;
622 s->mv[0][0][1] = 0;
623 s->mb_skipped = !(s->obmc | s->loop_filter);
624 goto end;
625 }
626 cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
627 if (cbpc < 0){
628 av_log(s->avctx, AV_LOG_ERROR, "cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
629 return -1;
630 }
631 }while(cbpc == 20);
632
633 s->bdsp.clear_blocks(s->block[0]);
634
635 dquant = cbpc & 8;
636 s->mb_intra = ((cbpc & 4) != 0);
637 if (s->mb_intra) goto intra;
638
639 if(s->pb_frame && get_bits1(&s->gb))
640 pb_mv_count = h263_get_modb(&s->gb, s->pb_frame, &cbpb);
641 cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
642
643 if(s->alt_inter_vlc==0 || (cbpc & 3)!=3)
644 cbpy ^= 0xF;
645
646 cbp = (cbpc & 3) | (cbpy << 2);
647 if (dquant) {
648 h263_decode_dquant(s);
649 }
650
651 s->mv_dir = MV_DIR_FORWARD;
652 if ((cbpc & 16) == 0) {
653 s->current_picture.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
654 /* 16x16 motion prediction */
655 s->mv_type = MV_TYPE_16X16;
656 ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
657 if (s->umvplus)
658 mx = h263p_decode_umotion(s, pred_x);
659 else
660 mx = ff_h263_decode_motion(s, pred_x, 1);
661
662 if (mx >= 0xffff)
663 return -1;
664
665 if (s->umvplus)
666 my = h263p_decode_umotion(s, pred_y);
667 else
668 my = ff_h263_decode_motion(s, pred_y, 1);
669
670 if (my >= 0xffff)
671 return -1;
672 s->mv[0][0][0] = mx;
673 s->mv[0][0][1] = my;
674
675 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
676 skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
677 } else {
678 s->current_picture.mb_type[xy] = MB_TYPE_8x8 | MB_TYPE_L0;
679 s->mv_type = MV_TYPE_8X8;
680 for(i=0;i<4;i++) {
681 mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
682 if (s->umvplus)
683 mx = h263p_decode_umotion(s, pred_x);
684 else
685 mx = ff_h263_decode_motion(s, pred_x, 1);
686 if (mx >= 0xffff)
687 return -1;
688
689 if (s->umvplus)
690 my = h263p_decode_umotion(s, pred_y);
691 else
692 my = ff_h263_decode_motion(s, pred_y, 1);
693 if (my >= 0xffff)
694 return -1;
695 s->mv[0][i][0] = mx;
696 s->mv[0][i][1] = my;
697 if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
698 skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
699 mot_val[0] = mx;
700 mot_val[1] = my;
701 }
702 }
703 } else if(s->pict_type==AV_PICTURE_TYPE_B) {
704 int mb_type;
705 const int stride= s->b8_stride;
706 int16_t *mot_val0 = s->current_picture.motion_val[0][2 * (s->mb_x + s->mb_y * stride)];
707 int16_t *mot_val1 = s->current_picture.motion_val[1][2 * (s->mb_x + s->mb_y * stride)];
708 // const int mv_xy= s->mb_x + 1 + s->mb_y * s->mb_stride;
709
710 //FIXME ugly
711 mot_val0[0 ]= mot_val0[2 ]= mot_val0[0+2*stride]= mot_val0[2+2*stride]=
712 mot_val0[1 ]= mot_val0[3 ]= mot_val0[1+2*stride]= mot_val0[3+2*stride]=
713 mot_val1[0 ]= mot_val1[2 ]= mot_val1[0+2*stride]= mot_val1[2+2*stride]=
714 mot_val1[1 ]= mot_val1[3 ]= mot_val1[1+2*stride]= mot_val1[3+2*stride]= 0;
715
716 do{
717 mb_type= get_vlc2(&s->gb, h263_mbtype_b_vlc.table, H263_MBTYPE_B_VLC_BITS, 2);
718 if (mb_type < 0){
719 av_log(s->avctx, AV_LOG_ERROR, "b mb_type damaged at %d %d\n", s->mb_x, s->mb_y);
720 return -1;
721 }
722
723 mb_type= h263_mb_type_b_map[ mb_type ];
724 }while(!mb_type);
725
726 s->mb_intra = IS_INTRA(mb_type);
727 if(HAS_CBP(mb_type)){
728 s->bdsp.clear_blocks(s->block[0]);
729 cbpc = get_vlc2(&s->gb, cbpc_b_vlc.table, CBPC_B_VLC_BITS, 1);
730 if(s->mb_intra){
731 dquant = IS_QUANT(mb_type);
732 goto intra;
733 }
734
735 cbpy = get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
736
737 if (cbpy < 0){
738 av_log(s->avctx, AV_LOG_ERROR, "b cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
739 return -1;
740 }
741
742 if(s->alt_inter_vlc==0 || (cbpc & 3)!=3)
743 cbpy ^= 0xF;
744
745 cbp = (cbpc & 3) | (cbpy << 2);
746 }else
747 cbp=0;
748
749 assert(!s->mb_intra);
750
751 if(IS_QUANT(mb_type)){
752 h263_decode_dquant(s);
753 }
754
755 if(IS_DIRECT(mb_type)){
756 if (!s->pp_time)
757 return AVERROR_INVALIDDATA;
758 s->mv_dir = MV_DIR_FORWARD | MV_DIR_BACKWARD | MV_DIRECT;
759 mb_type |= ff_mpeg4_set_direct_mv(s, 0, 0);
760 }else{
761 s->mv_dir = 0;
762 s->mv_type= MV_TYPE_16X16;
763 //FIXME UMV
764
765 if(USES_LIST(mb_type, 0)){
766 int16_t *mot_val= ff_h263_pred_motion(s, 0, 0, &mx, &my);
767 s->mv_dir = MV_DIR_FORWARD;
768
769 mx = ff_h263_decode_motion(s, mx, 1);
770 my = ff_h263_decode_motion(s, my, 1);
771
772 s->mv[0][0][0] = mx;
773 s->mv[0][0][1] = my;
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;
776 }
777
778 if(USES_LIST(mb_type, 1)){
779 int16_t *mot_val= ff_h263_pred_motion(s, 0, 1, &mx, &my);
780 s->mv_dir |= MV_DIR_BACKWARD;
781
782 mx = ff_h263_decode_motion(s, mx, 1);
783 my = ff_h263_decode_motion(s, my, 1);
784
785 s->mv[1][0][0] = mx;
786 s->mv[1][0][1] = my;
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;
789 }
790 }
791
792 s->current_picture.mb_type[xy] = mb_type;
793 } else { /* I-Frame */
794 do{
795 cbpc = get_vlc2(&s->gb, ff_h263_intra_MCBPC_vlc.table, INTRA_MCBPC_VLC_BITS, 2);
796 if (cbpc < 0){
797 av_log(s->avctx, AV_LOG_ERROR, "I cbpc damaged at %d %d\n", s->mb_x, s->mb_y);
798 return -1;
799 }
800 }while(cbpc == 8);
801
802 s->bdsp.clear_blocks(s->block[0]);
803
804 dquant = cbpc & 4;
805 s->mb_intra = 1;
806 intra:
807 s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
808 if (s->h263_aic) {
809 s->ac_pred = get_bits1(&s->gb);
810 if(s->ac_pred){
811 s->current_picture.mb_type[xy] = MB_TYPE_INTRA | MB_TYPE_ACPRED;
812
813 s->h263_aic_dir = get_bits1(&s->gb);
814 }
815 }else
816 s->ac_pred = 0;
817
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);
821 if(cbpy<0){
822 av_log(s->avctx, AV_LOG_ERROR, "I cbpy damaged at %d %d\n", s->mb_x, s->mb_y);
823 return -1;
824 }
825 cbp = (cbpc & 3) | (cbpy << 2);
826 if (dquant) {
827 h263_decode_dquant(s);
828 }
829
830 pb_mv_count += !!s->pb_frame;
831 }
832
833 while(pb_mv_count--){
834 ff_h263_decode_motion(s, 0, 1);
835 ff_h263_decode_motion(s, 0, 1);
836 }
837
838 /* decode each block */
839 for (i = 0; i < 6; i++) {
840 if (h263_decode_block(s, block[i], i, cbp&32) < 0)
841 return -1;
842 cbp+=cbp;
843 }
844
845 if(s->pb_frame && h263_skip_b_part(s, cbpb) < 0)
846 return -1;
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)
849 preview_obmc(s);
850 }
851 end:
852
853 /* per-MB end of slice check */
854 {
855 int v= show_bits(&s->gb, 16);
856
857 if (get_bits_left(&s->gb) < 16) {
858 v >>= 16 - get_bits_left(&s->gb);
859 }
860
861 if(v==0)
862 return SLICE_END;
863 }
864
865 return SLICE_OK;
866 }
867
868 /* most is hardcoded. should extend to handle all h263 streams */
869 int ff_h263_decode_picture_header(MpegEncContext *s)
870 {
871 int format, width, height, i;
872 uint32_t startcode;
873
874 align_get_bits(&s->gb);
875
876 startcode= get_bits(&s->gb, 22-8);
877
878 for(i= get_bits_left(&s->gb); i>24; i-=8) {
879 startcode = ((startcode << 8) | get_bits(&s->gb, 8)) & 0x003FFFFF;
880
881 if(startcode == 0x20)
882 break;
883 }
884
885 if (startcode != 0x20) {
886 av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
887 return -1;
888 }
889 /* temporal reference */
890 i = get_bits(&s->gb, 8); /* picture timestamp */
891 if( (s->picture_number&~0xFF)+i < s->picture_number)
892 i+= 256;
893 s->picture_number= (s->picture_number&~0xFF) + i;
894
895 /* PTYPE starts here */
896 if (get_bits1(&s->gb) != 1) {
897 /* marker */
898 av_log(s->avctx, AV_LOG_ERROR, "Bad marker\n");
899 return -1;
900 }
901 if (get_bits1(&s->gb) != 0) {
902 av_log(s->avctx, AV_LOG_ERROR, "Bad H263 id\n");
903 return -1; /* h263 id */
904 }
905 skip_bits1(&s->gb); /* split screen off */
906 skip_bits1(&s->gb); /* camera off */
907 skip_bits1(&s->gb); /* freeze picture release off */
908
909 format = get_bits(&s->gb, 3);
910 /*
911 0 forbidden
912 1 sub-QCIF
913 10 QCIF
914 7 extended PTYPE (PLUSPTYPE)
915 */
916
917 if (format != 7 && format != 6) {
918 s->h263_plus = 0;
919 /* H.263v1 */
920 width = ff_h263_format[format][0];
921 height = ff_h263_format[format][1];
922 if (!width)
923 return -1;
924
925 s->pict_type = AV_PICTURE_TYPE_I + get_bits1(&s->gb);
926
927 s->h263_long_vectors = get_bits1(&s->gb);
928
929 if (get_bits1(&s->gb) != 0) {
930 av_log(s->avctx, AV_LOG_ERROR, "H263 SAC not supported\n");
931 return -1; /* SAC: off */
932 }
933 s->obmc= get_bits1(&s->gb); /* Advanced prediction mode */
934 s->unrestricted_mv = s->h263_long_vectors || s->obmc;
935
936 s->pb_frame = get_bits1(&s->gb);
937 s->chroma_qscale= s->qscale = get_bits(&s->gb, 5);
938 skip_bits1(&s->gb); /* Continuous Presence Multipoint mode: off */
939
940 s->width = width;
941 s->height = height;
942 s->avctx->sample_aspect_ratio= (AVRational){12,11};
943 s->avctx->framerate = (AVRational){ 30000, 1001 };
944 } else {
945 int ufep;
946
947 /* H.263v2 */
948 s->h263_plus = 1;
949 ufep = get_bits(&s->gb, 3); /* Update Full Extended PTYPE */
950
951 /* ufep other than 0 and 1 are reserved */
952 if (ufep == 1) {
953 /* OPPTYPE */
954 format = get_bits(&s->gb, 3);
955 ff_dlog(s->avctx, "ufep=1, format: %d\n", format);
956 s->custom_pcf= get_bits1(&s->gb);
957 s->umvplus = get_bits1(&s->gb); /* Unrestricted Motion Vector */
958 if (get_bits1(&s->gb) != 0) {
959 av_log(s->avctx, AV_LOG_ERROR, "Syntax-based Arithmetic Coding (SAC) not supported\n");
960 }
961 s->obmc= get_bits1(&s->gb); /* Advanced prediction mode */
962 s->h263_aic = get_bits1(&s->gb); /* Advanced Intra Coding (AIC) */
963 s->loop_filter= get_bits1(&s->gb);
964 s->unrestricted_mv = s->umvplus || s->obmc || s->loop_filter;
965
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");
969 }
970 if (get_bits1(&s->gb) != 0) {
971 av_log(s->avctx, AV_LOG_ERROR, "Independent Segment Decoding not supported\n");
972 }
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;
977
978 skip_bits(&s->gb, 1); /* Prevent start code emulation */
979
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);
983 return -1;
984 }
985
986 /* MPPTYPE */
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
994 default:
995 return -1;
996 }
997 skip_bits(&s->gb, 2);
998 s->no_rounding = get_bits1(&s->gb);
999 skip_bits(&s->gb, 4);
1000
1001 /* Get the picture dimensions */
1002 if (ufep) {
1003 if (format == 6) {
1004 /* Custom Picture Format (CPFMT) */
1005 s->aspect_ratio_info = get_bits(&s->gb, 4);
1006 ff_dlog(s->avctx, "aspect: %d\n", s->aspect_ratio_info);
1007 /* aspect ratios:
1008 0 - forbidden
1009 1 - 1:1
1010 2 - 12:11 (CIF 4:3)
1011 3 - 10:11 (525-type 4:3)
1012 4 - 16:11 (CIF 16:9)
1013 5 - 40:33 (525-type 16:9)
1014 6-14 - reserved
1015 */
1016 width = (get_bits(&s->gb, 9) + 1) * 4;
1017 skip_bits1(&s->gb);
1018 height = get_bits(&s->gb, 9) * 4;
1019 ff_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);
1024 }else{
1025 s->avctx->sample_aspect_ratio= ff_h263_pixel_aspect[s->aspect_ratio_info];
1026 }
1027 } else {
1028 width = ff_h263_format[format][0];
1029 height = ff_h263_format[format][1];
1030 s->avctx->sample_aspect_ratio= (AVRational){12,11};
1031 }
1032 if ((width == 0) || (height == 0))
1033 return -1;
1034 s->width = width;
1035 s->height = height;
1036
1037 if(s->custom_pcf){
1038 int gcd;
1039 s->avctx->framerate.num = 1800000;
1040 s->avctx->framerate.den = 1000 + get_bits1(&s->gb);
1041 s->avctx->framerate.den *= get_bits(&s->gb, 7);
1042 if(s->avctx->framerate.den == 0){
1043 av_log(s, AV_LOG_ERROR, "zero framerate\n");
1044 return -1;
1045 }
1046 gcd= av_gcd(s->avctx->framerate.den, s->avctx->framerate.num);
1047 s->avctx->framerate.den /= gcd;
1048 s->avctx->framerate.num /= gcd;
1049 }else{
1050 s->avctx->framerate = (AVRational){ 30000, 1001 };
1051 }
1052 }
1053
1054 if(s->custom_pcf){
1055 skip_bits(&s->gb, 2); //extended Temporal reference
1056 }
1057
1058 if (ufep) {
1059 if (s->umvplus) {
1060 if(get_bits1(&s->gb)==0) /* Unlimited Unrestricted Motion Vectors Indicator (UUI) */
1061 skip_bits1(&s->gb);
1062 }
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");
1066 }
1067 if (get_bits1(&s->gb) != 0) {
1068 av_log(s->avctx, AV_LOG_ERROR, "unordered slices not supported\n");
1069 }
1070 }
1071 }
1072
1073 s->qscale = get_bits(&s->gb, 5);
1074 }
1075
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;
1079
1080 if (s->pb_frame) {
1081 skip_bits(&s->gb, 3); /* Temporal reference for B-pictures */
1082 if (s->custom_pcf)
1083 skip_bits(&s->gb, 2); //extended Temporal reference
1084 skip_bits(&s->gb, 2); /* Quantization information for B-pictures */
1085 }
1086
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;
1091 }else{
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 ||
1096 s->pp_time <= 0){
1097 s->pp_time = 2;
1098 s->pb_time = 1;
1099 }
1100 ff_mpeg4_init_direct_mv(s);
1101 }
1102
1103 /* PEI */
1104 while (get_bits1(&s->gb) != 0) {
1105 skip_bits(&s->gb, 8);
1106 }
1107
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");
1111 return -1;
1112 }
1113
1114 ff_h263_decode_mba(s);
1115
1116 if (get_bits1(&s->gb) != 1) {
1117 av_log(s->avctx, AV_LOG_ERROR, "SEPB2 marker missing\n");
1118 return -1;
1119 }
1120 }
1121 s->f_code = 1;
1122
1123 if(s->h263_aic){
1124 s->y_dc_scale_table=
1125 s->c_dc_scale_table= ff_aic_dc_scale_table;
1126 }else{
1127 s->y_dc_scale_table=
1128 s->c_dc_scale_table= ff_mpeg1_dc_scale_table;
1129 }
1130
1131 ff_h263_show_pict_info(s);
1132 if (s->pict_type == AV_PICTURE_TYPE_I && s->codec_tag == AV_RL32("ZYGO")){
1133 int i,j;
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++){
1137 for(j=0; j<3; j++){
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);
1141 }
1142 av_log(s->avctx, AV_LOG_DEBUG, "\n");
1143 }
1144 for(i=0; i<50; i++) av_log(s->avctx, AV_LOG_DEBUG, "%d", get_bits1(&s->gb));
1145 }
1146
1147 return 0;
1148 }