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[libav.git] / libavcodec / mpeg12.c
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1/*
2 * MPEG1 encoder / MPEG2 decoder
3 * Copyright (c) 2000,2001 Gerard Lantau.
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
18 */
19#include <stdlib.h>
20#include <stdio.h>
21#include <string.h>
22#include "avcodec.h"
23#include "dsputil.h"
24#include "mpegvideo.h"
25
26#include "mpeg12data.h"
27
28//#define DEBUG
29
30#ifdef DEBUG
31#define dprintf(fmt,args...) printf(fmt, ## args)
32#else
33#define dprintf(fmt,args...)
34#endif
35
36/* Start codes. */
37#define SEQ_END_CODE 0x000001b7
38#define SEQ_START_CODE 0x000001b3
39#define GOP_START_CODE 0x000001b8
40#define PICTURE_START_CODE 0x00000100
41#define SLICE_MIN_START_CODE 0x00000101
42#define SLICE_MAX_START_CODE 0x000001af
43#define EXT_START_CODE 0x000001b5
44#define USER_START_CODE 0x000001b2
45
46static void mpeg1_encode_block(MpegEncContext *s,
47 DCTELEM *block,
48 int component);
49static void mpeg1_encode_motion(MpegEncContext *s, int val);
50static void mpeg1_skip_picture(MpegEncContext *s, int pict_num);
51static int mpeg1_decode_block(MpegEncContext *s,
52 DCTELEM *block,
53 int n);
54static int mpeg2_decode_block_non_intra(MpegEncContext *s,
55 DCTELEM *block,
56 int n);
57static int mpeg2_decode_block_intra(MpegEncContext *s,
58 DCTELEM *block,
59 int n);
60static int mpeg_decode_motion(MpegEncContext *s, int fcode, int pred);
61
62static void put_header(MpegEncContext *s, int header)
63{
64 align_put_bits(&s->pb);
65 put_bits(&s->pb, 32, header);
66}
67
68/* put sequence header if needed */
69static void mpeg1_encode_sequence_header(MpegEncContext *s)
70{
71 unsigned int vbv_buffer_size;
72 unsigned int fps, n, v;
73 UINT64 time_code;
74
75 if ((s->picture_number % s->gop_size) == 0) {
76 /* mpeg1 header repeated every gop */
77 put_header(s, SEQ_START_CODE);
78
79 /* search closest frame rate */
80 {
81 int i, dmin, d;
82 s->frame_rate_index = 0;
83 dmin = 0x7fffffff;
84 for(i=1;i<9;i++) {
85 d = abs(s->frame_rate - frame_rate_tab[i]);
86 if (d < dmin) {
87 dmin = d;
88 s->frame_rate_index = i;
89 }
90 }
91 }
92
93 put_bits(&s->pb, 12, s->width);
94 put_bits(&s->pb, 12, s->height);
95 put_bits(&s->pb, 4, 1); /* 1/1 aspect ratio */
96 put_bits(&s->pb, 4, s->frame_rate_index);
97 v = s->bit_rate / 400;
98 if (v > 0x3ffff)
99 v = 0x3ffff;
100 put_bits(&s->pb, 18, v);
101 put_bits(&s->pb, 1, 1); /* marker */
102 /* vbv buffer size: slightly greater than an I frame. We add
103 some margin just in case */
104 vbv_buffer_size = (3 * s->I_frame_bits) / (2 * 8);
105 put_bits(&s->pb, 10, (vbv_buffer_size + 16383) / 16384);
106 put_bits(&s->pb, 1, 1); /* constrained parameter flag */
107 put_bits(&s->pb, 1, 0); /* no custom intra matrix */
108 put_bits(&s->pb, 1, 0); /* no custom non intra matrix */
109
110 put_header(s, GOP_START_CODE);
111 put_bits(&s->pb, 1, 0); /* do drop frame */
112 /* time code : we must convert from the real frame rate to a
113 fake mpeg frame rate in case of low frame rate */
114 fps = frame_rate_tab[s->frame_rate_index];
115 time_code = s->fake_picture_number * FRAME_RATE_BASE;
116 s->gop_picture_number = s->fake_picture_number;
117 put_bits(&s->pb, 5, (time_code / (fps * 3600)) % 24);
118 put_bits(&s->pb, 6, (time_code / (fps * 60)) % 60);
119 put_bits(&s->pb, 1, 1);
120 put_bits(&s->pb, 6, (time_code / fps) % 60);
121 put_bits(&s->pb, 6, (time_code % fps) / FRAME_RATE_BASE);
122 put_bits(&s->pb, 1, 1); /* closed gop */
123 put_bits(&s->pb, 1, 0); /* broken link */
124 }
125
126 if (s->frame_rate < (24 * FRAME_RATE_BASE) && s->picture_number > 0) {
127 /* insert empty P pictures to slow down to the desired
128 frame rate. Each fake pictures takes about 20 bytes */
129 fps = frame_rate_tab[s->frame_rate_index];
130 n = ((s->picture_number * fps) / s->frame_rate) - 1;
131 while (s->fake_picture_number < n) {
132 mpeg1_skip_picture(s, s->fake_picture_number -
133 s->gop_picture_number);
134 s->fake_picture_number++;
135 }
136
137 }
138 s->fake_picture_number++;
139}
140
141
142/* insert a fake P picture */
143static void mpeg1_skip_picture(MpegEncContext *s, int pict_num)
144{
145 unsigned int mb_incr;
146
147 /* mpeg1 picture header */
148 put_header(s, PICTURE_START_CODE);
149 /* temporal reference */
150 put_bits(&s->pb, 10, pict_num & 0x3ff);
151
152 put_bits(&s->pb, 3, P_TYPE);
153 put_bits(&s->pb, 16, 0xffff); /* non constant bit rate */
154
155 put_bits(&s->pb, 1, 1); /* integer coordinates */
156 put_bits(&s->pb, 3, 1); /* forward_f_code */
157
158 put_bits(&s->pb, 1, 0); /* extra bit picture */
159
160 /* only one slice */
161 put_header(s, SLICE_MIN_START_CODE);
162 put_bits(&s->pb, 5, 1); /* quantizer scale */
163 put_bits(&s->pb, 1, 0); /* slice extra information */
164
165 mb_incr = 1;
166 put_bits(&s->pb, mbAddrIncrTable[mb_incr - 1][1],
167 mbAddrIncrTable[mb_incr - 1][0]);
168
169 /* empty macroblock */
170 put_bits(&s->pb, 3, 1); /* motion only */
171
172 /* zero motion x & y */
173 put_bits(&s->pb, 1, 1);
174 put_bits(&s->pb, 1, 1);
175
176 /* output a number of empty slice */
177 mb_incr = s->mb_width * s->mb_height - 1;
178 while (mb_incr > 33) {
179 put_bits(&s->pb, 11, 0x008);
180 mb_incr -= 33;
181 }
182 put_bits(&s->pb, mbAddrIncrTable[mb_incr - 1][1],
183 mbAddrIncrTable[mb_incr - 1][0]);
184
185 /* empty macroblock */
186 put_bits(&s->pb, 3, 1); /* motion only */
187
188 /* zero motion x & y */
189 put_bits(&s->pb, 1, 1);
190 put_bits(&s->pb, 1, 1);
191}
192
193void mpeg1_encode_picture_header(MpegEncContext *s, int picture_number)
194{
195 static int done;
196
197 if (!done) {
198 done = 1;
199 init_rl(&rl_mpeg1);
200 }
201 mpeg1_encode_sequence_header(s);
202
203 /* mpeg1 picture header */
204 put_header(s, PICTURE_START_CODE);
205 /* temporal reference */
206 put_bits(&s->pb, 10, (s->fake_picture_number -
207 s->gop_picture_number) & 0x3ff);
208
209 put_bits(&s->pb, 3, s->pict_type);
210 put_bits(&s->pb, 16, 0xffff); /* non constant bit rate */
211
212 if (s->pict_type == P_TYPE) {
213 put_bits(&s->pb, 1, 0); /* half pel coordinates */
214 put_bits(&s->pb, 3, s->f_code); /* forward_f_code */
215 }
216
217 put_bits(&s->pb, 1, 0); /* extra bit picture */
218
219 /* only one slice */
220 put_header(s, SLICE_MIN_START_CODE);
221 put_bits(&s->pb, 5, s->qscale); /* quantizer scale */
222 put_bits(&s->pb, 1, 0); /* slice extra information */
223}
224
225void mpeg1_encode_mb(MpegEncContext *s,
226 DCTELEM block[6][64],
227 int motion_x, int motion_y)
228{
229 int mb_incr, i, cbp, mb_x, mb_y;
230
231 mb_x = s->mb_x;
232 mb_y = s->mb_y;
233
234 /* compute cbp */
235 cbp = 0;
236 for(i=0;i<6;i++) {
237 if (s->block_last_index[i] >= 0)
238 cbp |= 1 << (5 - i);
239 }
240
241 /* skip macroblock, except if first or last macroblock of a slice */
242 if ((cbp | motion_x | motion_y) == 0 &&
243 (!((mb_x | mb_y) == 0 ||
244 (mb_x == s->mb_width - 1 && mb_y == s->mb_height - 1)))) {
245 s->mb_incr++;
246 } else {
247 /* output mb incr */
248 mb_incr = s->mb_incr;
249
250 while (mb_incr > 33) {
251 put_bits(&s->pb, 11, 0x008);
252 mb_incr -= 33;
253 }
254 put_bits(&s->pb, mbAddrIncrTable[mb_incr - 1][1],
255 mbAddrIncrTable[mb_incr - 1][0]);
256
257 if (s->pict_type == I_TYPE) {
258 put_bits(&s->pb, 1, 1); /* macroblock_type : macroblock_quant = 0 */
259 } else {
260 if (s->mb_intra) {
261 put_bits(&s->pb, 5, 0x03);
262 } else {
263 if (cbp != 0) {
264 if (motion_x == 0 && motion_y == 0) {
265 put_bits(&s->pb, 2, 1); /* macroblock_pattern only */
266 put_bits(&s->pb, mbPatTable[cbp - 1][1], mbPatTable[cbp - 1][0]);
267 } else {
268 put_bits(&s->pb, 1, 1); /* motion + cbp */
269 mpeg1_encode_motion(s, motion_x - s->last_mv[0][0][0]);
270 mpeg1_encode_motion(s, motion_y - s->last_mv[0][0][1]);
271 put_bits(&s->pb, mbPatTable[cbp - 1][1], mbPatTable[cbp - 1][0]);
272 }
273 } else {
274 put_bits(&s->pb, 3, 1); /* motion only */
275 mpeg1_encode_motion(s, motion_x - s->last_mv[0][0][0]);
276 mpeg1_encode_motion(s, motion_y - s->last_mv[0][0][1]);
277 }
278 }
279 }
280 for(i=0;i<6;i++) {
281 if (cbp & (1 << (5 - i))) {
282 mpeg1_encode_block(s, block[i], i);
283 }
284 }
285 s->mb_incr = 1;
286 }
287 s->last_mv[0][0][0] = motion_x;
288 s->last_mv[0][0][1] = motion_y;
289}
290
291static void mpeg1_encode_motion(MpegEncContext *s, int val)
292{
293 int code, bit_size, l, m, bits, range, sign;
294
295 if (val == 0) {
296 /* zero vector */
297 code = 0;
298 put_bits(&s->pb,
299 mbMotionVectorTable[0][1],
300 mbMotionVectorTable[0][0]);
301 } else {
302 bit_size = s->f_code - 1;
303 range = 1 << bit_size;
304 /* modulo encoding */
305 l = 16 * range;
306 m = 2 * l;
307 if (val < -l) {
308 val += m;
309 } else if (val >= l) {
310 val -= m;
311 }
312
313 if (val >= 0) {
314 val--;
315 code = (val >> bit_size) + 1;
316 bits = val & (range - 1);
317 sign = 0;
318 } else {
319 val = -val;
320 val--;
321 code = (val >> bit_size) + 1;
322 bits = val & (range - 1);
323 sign = 1;
324 }
325 put_bits(&s->pb,
326 mbMotionVectorTable[code][1],
327 mbMotionVectorTable[code][0]);
328 put_bits(&s->pb, 1, sign);
329 if (bit_size > 0) {
330 put_bits(&s->pb, bit_size, bits);
331 }
332 }
333}
334
335static inline void encode_dc(MpegEncContext *s, int diff, int component)
336{
337 int adiff, index;
338
339 adiff = abs(diff);
340 index = vlc_dc_table[adiff];
341 if (component == 0) {
342 put_bits(&s->pb, vlc_dc_lum_bits[index], vlc_dc_lum_code[index]);
343 } else {
344 put_bits(&s->pb, vlc_dc_chroma_bits[index], vlc_dc_chroma_code[index]);
345 }
346 if (diff > 0) {
347 put_bits(&s->pb, index, (diff & ((1 << index) - 1)));
348 } else if (diff < 0) {
349 put_bits(&s->pb, index, ((diff - 1) & ((1 << index) - 1)));
350 }
351}
352
353static void mpeg1_encode_block(MpegEncContext *s,
354 DCTELEM *block,
355 int n)
356{
357 int alevel, level, last_non_zero, dc, diff, i, j, run, last_index, sign;
358 int code, component;
359 RLTable *rl = &rl_mpeg1;
360
361 last_index = s->block_last_index[n];
362
363 /* DC coef */
364 if (s->mb_intra) {
365 component = (n <= 3 ? 0 : n - 4 + 1);
366 dc = block[0]; /* overflow is impossible */
367 diff = dc - s->last_dc[component];
368 encode_dc(s, diff, component);
369 s->last_dc[component] = dc;
370 i = 1;
371 } else {
372 /* encode the first coefficient : needs to be done here because
373 it is handled slightly differently */
374 level = block[0];
375 if (abs(level) == 1) {
376 code = ((UINT32)level >> 31); /* the sign bit */
377 put_bits(&s->pb, 2, code | 0x02);
378 i = 1;
379 } else {
380 i = 0;
381 last_non_zero = -1;
382 goto next_coef;
383 }
384 }
385
386 /* now quantify & encode AC coefs */
387 last_non_zero = i - 1;
388 for(;i<=last_index;i++) {
389 j = zigzag_direct[i];
390 level = block[j];
391 next_coef:
392#if 0
393 if (level != 0)
394 dprintf("level[%d]=%d\n", i, level);
395#endif
396 /* encode using VLC */
397 if (level != 0) {
398 run = i - last_non_zero - 1;
399 sign = 0;
400 alevel = level;
401 if (alevel < 0) {
402 sign = 1;
403 alevel = -alevel;
404 }
405 code = get_rl_index(rl, 0, run, alevel);
406 put_bits(&s->pb, rl->table_vlc[code][1], rl->table_vlc[code][0]);
407 if (code != rl->n) {
408 put_bits(&s->pb, 1, sign);
409 } else {
410 /* escape: only clip in this case */
411 put_bits(&s->pb, 6, run);
412 if (alevel < 128) {
413 put_bits(&s->pb, 8, level & 0xff);
414 } else {
415 if (level < 0) {
416 put_bits(&s->pb, 16, 0x8001 + level + 255);
417 } else {
418 put_bits(&s->pb, 16, level & 0xffff);
419 }
420 }
421 }
422 last_non_zero = i;
423 }
424 }
425 /* end of block */
426 put_bits(&s->pb, 2, 0x2);
427}
428
429/******************************************/
430/* decoding */
431
432static VLC dc_lum_vlc;
433static VLC dc_chroma_vlc;
434static VLC mv_vlc;
435static VLC mbincr_vlc;
436static VLC mb_ptype_vlc;
437static VLC mb_btype_vlc;
438static VLC mb_pat_vlc;
439
440void mpeg1_init_vlc(MpegEncContext *s)
441{
442 static int done = 0;
443
444 if (!done) {
445
446 init_vlc(&dc_lum_vlc, 9, 12,
447 vlc_dc_lum_bits, 1, 1,
448 vlc_dc_lum_code, 2, 2);
449 init_vlc(&dc_chroma_vlc, 9, 12,
450 vlc_dc_chroma_bits, 1, 1,
451 vlc_dc_chroma_code, 2, 2);
452 init_vlc(&mv_vlc, 9, 17,
453 &mbMotionVectorTable[0][1], 2, 1,
454 &mbMotionVectorTable[0][0], 2, 1);
455 init_vlc(&mbincr_vlc, 9, 34,
456 &mbAddrIncrTable[0][1], 2, 1,
457 &mbAddrIncrTable[0][0], 2, 1);
458 init_vlc(&mb_pat_vlc, 9, 63,
459 &mbPatTable[0][1], 2, 1,
460 &mbPatTable[0][0], 2, 1);
461
462 init_vlc(&mb_ptype_vlc, 6, 32,
463 &table_mb_ptype[0][1], 2, 1,
464 &table_mb_ptype[0][0], 2, 1);
465 init_vlc(&mb_btype_vlc, 6, 32,
466 &table_mb_btype[0][1], 2, 1,
467 &table_mb_btype[0][0], 2, 1);
468 init_rl(&rl_mpeg1);
469 init_rl(&rl_mpeg2);
470 /* cannot use generic init because we must add the EOB code */
471 init_vlc(&rl_mpeg1.vlc, 9, rl_mpeg1.n + 2,
472 &rl_mpeg1.table_vlc[0][1], 4, 2,
473 &rl_mpeg1.table_vlc[0][0], 4, 2);
474 init_vlc(&rl_mpeg2.vlc, 9, rl_mpeg2.n + 2,
475 &rl_mpeg2.table_vlc[0][1], 4, 2,
476 &rl_mpeg2.table_vlc[0][0], 4, 2);
477 }
478}
479
480static inline int get_dmv(MpegEncContext *s)
481{
482 if(get_bits(&s->gb, 1))
483 return 1 - (get_bits(&s->gb, 1) << 1);
484 else
485 return 0;
486}
487
488/* motion type (for mpeg2) */
489#define MT_FIELD 1
490#define MT_FRAME 2
491#define MT_16X8 2
492#define MT_DMV 3
493
494static int mpeg_decode_mb(MpegEncContext *s,
495 DCTELEM block[6][64])
496{
497 int i, j, k, cbp, val, code, mb_type, motion_type;
498
499 /* skip mb handling */
500 if (s->mb_incr == 0) {
501 /* read again increment */
502 s->mb_incr = 1;
503 for(;;) {
504 code = get_vlc(&s->gb, &mbincr_vlc);
505 if (code < 0)
506 return 1; /* error = end of slice */
507 if (code >= 33) {
508 if (code == 33) {
509 s->mb_incr += 33;
510 }
511 /* otherwise, stuffing, nothing to do */
512 } else {
513 s->mb_incr += code;
514 break;
515 }
516 }
517 }
518 if (++s->mb_x >= s->mb_width) {
519 s->mb_x = 0;
520 if (s->mb_y >= (s->mb_height - 1))
521 return -1;
522 s->mb_y++;
523 }
524 dprintf("decode_mb: x=%d y=%d\n", s->mb_x, s->mb_y);
525
526 if (--s->mb_incr != 0) {
527 /* skip mb */
528 s->mb_intra = 0;
529 for(i=0;i<6;i++)
530 s->block_last_index[i] = -1;
531 s->mv_type = MV_TYPE_16X16;
532 if (s->pict_type == P_TYPE) {
533 /* if P type, zero motion vector is implied */
534 s->mv_dir = MV_DIR_FORWARD;
535 s->mv[0][0][0] = s->mv[0][0][1] = 0;
536 s->last_mv[0][0][0] = s->last_mv[0][0][1] = 0;
537 } else {
538 /* if B type, reuse previous vectors and directions */
539 s->mv[0][0][0] = s->last_mv[0][0][0];
540 s->mv[0][0][1] = s->last_mv[0][0][1];
541 s->mv[1][0][0] = s->last_mv[1][0][0];
542 s->mv[1][0][1] = s->last_mv[1][0][1];
543 }
544 return 0;
545 }
546
547 switch(s->pict_type) {
548 default:
549 case I_TYPE:
550 if (get_bits(&s->gb, 1) == 0) {
551 if (get_bits(&s->gb, 1) == 0)
552 return -1;
553 mb_type = MB_QUANT | MB_INTRA;
554 } else {
555 mb_type = MB_INTRA;
556 }
557 break;
558 case P_TYPE:
559 mb_type = get_vlc(&s->gb, &mb_ptype_vlc);
560 if (mb_type < 0)
561 return -1;
562 break;
563 case B_TYPE:
564 mb_type = get_vlc(&s->gb, &mb_btype_vlc);
565 if (mb_type < 0)
566 return -1;
567 break;
568 }
569 dprintf("mb_type=%x\n", mb_type);
570 motion_type = 0; /* avoid warning */
571 if (mb_type & (MB_FOR|MB_BACK)) {
572 /* get additionnal motion vector type */
573 if (s->picture_structure == PICT_FRAME && s->frame_pred_frame_dct)
574 motion_type = MT_FRAME;
575 else
576 motion_type = get_bits(&s->gb, 2);
577 }
578 /* compute dct type */
579 if (s->picture_structure == PICT_FRAME &&
580 !s->frame_pred_frame_dct &&
581 (mb_type & (MB_PAT | MB_INTRA))) {
582 s->interlaced_dct = get_bits(&s->gb, 1);
583#ifdef DEBUG
584 if (s->interlaced_dct)
585 printf("interlaced_dct\n");
586#endif
587 } else {
588 s->interlaced_dct = 0; /* frame based */
589 }
590
591 if (mb_type & MB_QUANT) {
592 if (s->mpeg2) {
593 if (s->q_scale_type) {
594 s->qscale = non_linear_qscale[get_bits(&s->gb, 5)];
595 } else {
596 s->qscale = get_bits(&s->gb, 5) << 1;
597 }
598 } else {
599 /* for mpeg1, we use the generic unquant code */
600 s->qscale = get_bits(&s->gb, 5);
601 }
602 }
603 if (mb_type & MB_INTRA) {
604 if (s->concealment_motion_vectors) {
605 /* just parse them */
606 if (s->picture_structure != PICT_FRAME)
607 get_bits(&s->gb, 1); /* field select */
608 mpeg_decode_motion(s, s->mpeg_f_code[0][0], 0);
609 mpeg_decode_motion(s, s->mpeg_f_code[0][1], 0);
610 }
611 s->mb_intra = 1;
612 cbp = 0x3f;
613 memset(s->last_mv, 0, sizeof(s->last_mv)); /* reset mv prediction */
614 } else {
615 s->mb_intra = 0;
616 cbp = 0;
617 }
618 /* special case of implicit zero motion vector */
619 if (s->pict_type == P_TYPE && !(mb_type & MB_FOR)) {
620 s->mv_dir = MV_DIR_FORWARD;
621 s->mv_type = MV_TYPE_16X16;
622 s->last_mv[0][0][0] = 0;
623 s->last_mv[0][0][1] = 0;
624 s->mv[0][0][0] = 0;
625 s->mv[0][0][1] = 0;
626 } else if (mb_type & (MB_FOR | MB_BACK)) {
627 /* motion vectors */
628 s->mv_dir = 0;
629 for(i=0;i<2;i++) {
630 if (mb_type & (MB_FOR >> i)) {
631 s->mv_dir |= (MV_DIR_FORWARD >> i);
632 dprintf("mv_type=%d\n", motion_type);
633 switch(motion_type) {
634 case MT_FRAME: /* or MT_16X8 */
635 if (s->picture_structure == PICT_FRAME) {
636 /* MT_FRAME */
637 s->mv_type = MV_TYPE_16X16;
638 for(k=0;k<2;k++) {
639 val = mpeg_decode_motion(s, s->mpeg_f_code[i][k],
640 s->last_mv[i][0][k]);
641 s->last_mv[i][0][k] = val;
642 s->last_mv[i][1][k] = val;
643 /* full_pel: only for mpeg1 */
644 if (s->full_pel[i])
645 val = val << 1;
646 s->mv[i][0][k] = val;
647 dprintf("mv%d: %d\n", k, val);
648 }
649 } else {
650 /* MT_16X8 */
651 s->mv_type = MV_TYPE_16X8;
652 for(j=0;j<2;j++) {
653 s->field_select[i][j] = get_bits(&s->gb, 1);
654 for(k=0;k<2;k++) {
655 val = mpeg_decode_motion(s, s->mpeg_f_code[i][k],
656 s->last_mv[i][j][k]);
657 s->last_mv[i][j][k] = val;
658 s->mv[i][j][k] = val;
659 }
660 }
661 }
662 break;
663 case MT_FIELD:
664 if (s->picture_structure == PICT_FRAME) {
665 s->mv_type = MV_TYPE_FIELD;
666 for(j=0;j<2;j++) {
667 s->field_select[i][j] = get_bits(&s->gb, 1);
668 val = mpeg_decode_motion(s, s->mpeg_f_code[i][0],
669 s->last_mv[i][j][0]);
670 s->last_mv[i][j][0] = val;
671 s->mv[i][j][0] = val;
672 dprintf("fmx=%d\n", val);
673 val = mpeg_decode_motion(s, s->mpeg_f_code[i][1],
674 s->last_mv[i][j][1] >> 1);
675 s->last_mv[i][j][1] = val << 1;
676 s->mv[i][j][1] = val;
677 dprintf("fmy=%d\n", val);
678 }
679 } else {
680 s->mv_type = MV_TYPE_16X16;
681 s->field_select[i][0] = get_bits(&s->gb, 1);
682 for(k=0;k<2;k++) {
683 val = mpeg_decode_motion(s, s->mpeg_f_code[i][k],
684 s->last_mv[i][0][k]);
685 s->last_mv[i][0][k] = val;
686 s->last_mv[i][1][k] = val;
687 s->mv[i][0][k] = val;
688 }
689 }
690 break;
691 case MT_DMV:
692 {
693 int dmx, dmy, mx, my, m;
694
695 mx = mpeg_decode_motion(s, s->mpeg_f_code[i][0],
696 s->last_mv[i][0][0]);
697 s->last_mv[i][0][0] = mx;
698 s->last_mv[i][1][0] = mx;
699 dmx = get_dmv(s);
700 my = mpeg_decode_motion(s, s->mpeg_f_code[i][1],
701 s->last_mv[i][0][1] >> 1);
702 dmy = get_dmv(s);
703 s->mv_type = MV_TYPE_DMV;
704 /* XXX: totally broken */
705 if (s->picture_structure == PICT_FRAME) {
706 s->last_mv[i][0][1] = my << 1;
707 s->last_mv[i][1][1] = my << 1;
708
709 m = s->top_field_first ? 1 : 3;
710 /* top -> top pred */
711 s->mv[i][0][0] = mx;
712 s->mv[i][0][1] = my << 1;
713 s->mv[i][1][0] = ((mx * m + (mx > 0)) >> 1) + dmx;
714 s->mv[i][1][1] = ((my * m + (my > 0)) >> 1) + dmy - 1;
715 m = 4 - m;
716 s->mv[i][2][0] = mx;
717 s->mv[i][2][1] = my << 1;
718 s->mv[i][3][0] = ((mx * m + (mx > 0)) >> 1) + dmx;
719 s->mv[i][3][1] = ((my * m + (my > 0)) >> 1) + dmy + 1;
720 } else {
721 s->last_mv[i][0][1] = my;
722 s->last_mv[i][1][1] = my;
723 s->mv[i][0][0] = mx;
724 s->mv[i][0][1] = my;
725 s->mv[i][1][0] = ((mx + (mx > 0)) >> 1) + dmx;
726 s->mv[i][1][1] = ((my + (my > 0)) >> 1) + dmy - 1
727 /* + 2 * cur_field */;
728 }
729 }
730 break;
731 }
732 }
733 }
734 }
735
736 if ((mb_type & MB_INTRA) && s->concealment_motion_vectors) {
737 get_bits(&s->gb, 1); /* marker */
738 }
739
740 if (mb_type & MB_PAT) {
741 cbp = get_vlc(&s->gb, &mb_pat_vlc);
742 if (cbp < 0)
743 return -1;
744 cbp++;
745 }
746 dprintf("cbp=%x\n", cbp);
747
748 if (s->mpeg2) {
749 if (s->mb_intra) {
750 for(i=0;i<6;i++) {
751 if (cbp & (1 << (5 - i))) {
752 if (mpeg2_decode_block_intra(s, block[i], i) < 0)
753 return -1;
754 }
755 }
756 } else {
757 for(i=0;i<6;i++) {
758 if (cbp & (1 << (5 - i))) {
759 if (mpeg2_decode_block_non_intra(s, block[i], i) < 0)
760 return -1;
761 }
762 }
763 }
764 } else {
765 for(i=0;i<6;i++) {
766 if (cbp & (1 << (5 - i))) {
767 if (mpeg1_decode_block(s, block[i], i) < 0)
768 return -1;
769 }
770 }
771 }
772 return 0;
773}
774
775/* as h263, but only 17 codes */
776static int mpeg_decode_motion(MpegEncContext *s, int fcode, int pred)
777{
778 int code, sign, val, m, l, shift;
779
780 code = get_vlc(&s->gb, &mv_vlc);
781 if (code < 0) {
782 return 0xffff;
783 }
784 if (code == 0) {
785 return pred;
786 }
787 sign = get_bits(&s->gb, 1);
788 shift = fcode - 1;
789 val = (code - 1) << shift;
790 if (shift > 0)
791 val |= get_bits(&s->gb, shift);
792 val++;
793 if (sign)
794 val = -val;
795 val += pred;
796
797 /* modulo decoding */
798 l = (1 << shift) * 16;
799 m = 2 * l;
800 if (val < -l) {
801 val += m;
802 } else if (val >= l) {
803 val -= m;
804 }
805 return val;
806}
807
808static inline int decode_dc(MpegEncContext *s, int component)
809{
810 int code, diff;
811
812 if (component == 0) {
813 code = get_vlc(&s->gb, &dc_lum_vlc);
814 } else {
815 code = get_vlc(&s->gb, &dc_chroma_vlc);
816 }
817 if (code < 0)
818 return 0xffff;
819 if (code == 0) {
820 diff = 0;
821 } else {
822 diff = get_bits(&s->gb, code);
823 if ((diff & (1 << (code - 1))) == 0)
824 diff = (-1 << code) | (diff + 1);
825 }
826 return diff;
827}
828
829static int mpeg1_decode_block(MpegEncContext *s,
830 DCTELEM *block,
831 int n)
832{
833 int level, dc, diff, i, j, run;
834 int code, component;
835 RLTable *rl = &rl_mpeg1;
836
837 if (s->mb_intra) {
838 /* DC coef */
839 component = (n <= 3 ? 0 : n - 4 + 1);
840 diff = decode_dc(s, component);
841 if (diff >= 0xffff)
842 return -1;
843 dc = s->last_dc[component];
844 dc += diff;
845 s->last_dc[component] = dc;
846 block[0] = dc;
847 dprintf("dc=%d diff=%d\n", dc, diff);
848 i = 1;
849 } else {
850 int bit_cnt, v;
851 UINT32 bit_buf;
852 UINT8 *buf_ptr;
853 i = 0;
854 /* special case for the first coef. no need to add a second vlc table */
855 SAVE_BITS(&s->gb);
856 SHOW_BITS(&s->gb, v, 2);
857 if (v & 2) {
858 run = 0;
859 level = 1 - ((v & 1) << 1);
860 FLUSH_BITS(2);
861 RESTORE_BITS(&s->gb);
862 goto add_coef;
863 }
864 RESTORE_BITS(&s->gb);
865 }
866
867 /* now quantify & encode AC coefs */
868 for(;;) {
869 code = get_vlc(&s->gb, &rl->vlc);
870 if (code < 0) {
871 return -1;
872 }
873 if (code == 112) {
874 break;
875 } else if (code == 111) {
876 /* escape */
877 run = get_bits(&s->gb, 6);
878 level = get_bits(&s->gb, 8);
879 level = (level << 24) >> 24;
880 if (level == -128) {
881 level = get_bits(&s->gb, 8) - 256;
882 } else if (level == 0) {
883 level = get_bits(&s->gb, 8);
884 }
885 } else {
886 run = rl->table_run[code];
887 level = rl->table_level[code];
888 if (get_bits(&s->gb, 1))
889 level = -level;
890 }
891 i += run;
892 if (i >= 64)
893 return -1;
894 add_coef:
895 dprintf("%d: run=%d level=%d\n", n, run, level);
896 j = zigzag_direct[i];
897 block[j] = level;
898 i++;
899 }
900 s->block_last_index[n] = i;
901 return 0;
902}
903
904/* Also does unquantization here, since I will never support mpeg2
905 encoding */
906static int mpeg2_decode_block_non_intra(MpegEncContext *s,
907 DCTELEM *block,
908 int n)
909{
910 int level, i, j, run;
911 int code;
912 RLTable *rl = &rl_mpeg1;
913 const UINT8 *scan_table;
914 const UINT16 *matrix;
915 int mismatch;
916
917 if (s->alternate_scan)
918 scan_table = ff_alternate_vertical_scan;
919 else
920 scan_table = zigzag_direct;
921 mismatch = 1;
922
923 {
924 int bit_cnt, v;
925 UINT32 bit_buf;
926 UINT8 *buf_ptr;
927 i = 0;
928 if (n < 4)
929 matrix = s->non_intra_matrix;
930 else
931 matrix = s->chroma_non_intra_matrix;
932
933 /* special case for the first coef. no need to add a second vlc table */
934 SAVE_BITS(&s->gb);
935 SHOW_BITS(&s->gb, v, 2);
936 if (v & 2) {
937 run = 0;
938 level = 1 - ((v & 1) << 1);
939 FLUSH_BITS(2);
940 RESTORE_BITS(&s->gb);
941 goto add_coef;
942 }
943 RESTORE_BITS(&s->gb);
944 }
945
946 /* now quantify & encode AC coefs */
947 for(;;) {
948 code = get_vlc(&s->gb, &rl->vlc);
949 if (code < 0)
950 return -1;
951 if (code == 112) {
952 break;
953 } else if (code == 111) {
954 /* escape */
955 run = get_bits(&s->gb, 6);
956 level = get_bits(&s->gb, 12);
957 level = (level << 20) >> 20;
958 } else {
959 run = rl->table_run[code];
960 level = rl->table_level[code];
961 if (get_bits(&s->gb, 1))
962 level = -level;
963 }
964 i += run;
965 if (i >= 64)
966 return -1;
967 add_coef:
968 j = scan_table[i];
969 dprintf("%d: run=%d level=%d\n", n, run, level);
970 level = ((level * 2 + 1) * s->qscale * matrix[j]) / 32;
971 /* XXX: is it really necessary to saturate since the encoder
972 knows whats going on ? */
973 mismatch ^= level;
974 block[j] = level;
975 i++;
976 }
977 block[63] ^= (mismatch & 1);
978 s->block_last_index[n] = i;
979 return 0;
980}
981
982static int mpeg2_decode_block_intra(MpegEncContext *s,
983 DCTELEM *block,
984 int n)
985{
986 int level, dc, diff, i, j, run;
987 int code, component;
988 RLTable *rl;
989 const UINT8 *scan_table;
990 const UINT16 *matrix;
991 int mismatch;
992
993 if (s->alternate_scan)
994 scan_table = ff_alternate_vertical_scan;
995 else
996 scan_table = zigzag_direct;
997 mismatch = 1;
998
999 /* DC coef */
1000 component = (n <= 3 ? 0 : n - 4 + 1);
1001 diff = decode_dc(s, component);
1002 if (diff >= 0xffff)
1003 return -1;
1004 dc = s->last_dc[component];
1005 dc += diff;
1006 s->last_dc[component] = dc;
1007 block[0] = dc << (3 - s->intra_dc_precision);
1008 dprintf("dc=%d\n", block[0]);
1009 i = 1;
1010 if (s->intra_vlc_format)
1011 rl = &rl_mpeg2;
1012 else
1013 rl = &rl_mpeg1;
1014 if (n < 4)
1015 matrix = s->intra_matrix;
1016 else
1017 matrix = s->chroma_intra_matrix;
1018
1019 /* now quantify & encode AC coefs */
1020 for(;;) {
1021 code = get_vlc(&s->gb, &rl->vlc);
1022 if (code < 0)
1023 return -1;
1024 if (code == 112) {
1025 break;
1026 } else if (code == 111) {
1027 /* escape */
1028 run = get_bits(&s->gb, 6);
1029 level = get_bits(&s->gb, 12);
1030 level = (level << 20) >> 20;
1031 } else {
1032 run = rl->table_run[code];
1033 level = rl->table_level[code];
1034 if (get_bits(&s->gb, 1))
1035 level = -level;
1036 }
1037 i += run;
1038 if (i >= 64)
1039 return -1;
1040 j = scan_table[i];
1041 dprintf("%d: run=%d level=%d\n", n, run, level);
1042 level = (level * s->qscale * matrix[j]) / 16;
1043 /* XXX: is it really necessary to saturate since the encoder
1044 knows whats going on ? */
1045 mismatch ^= level;
1046 block[j] = level;
1047 i++;
1048 }
1049 block[63] ^= (mismatch & 1);
1050 s->block_last_index[n] = i;
1051 return 0;
1052}
1053
1054/* compressed picture size */
1055#define PICTURE_BUFFER_SIZE 100000
1056
1057typedef struct Mpeg1Context {
1058 MpegEncContext mpeg_enc_ctx;
1059 UINT32 header_state;
1060 int start_code; /* current start code */
1061 UINT8 buffer[PICTURE_BUFFER_SIZE];
1062 UINT8 *buf_ptr;
1063 int buffer_size;
1064 int mpeg_enc_ctx_allocated; /* true if decoding context allocated */
1065} Mpeg1Context;
1066
1067static int mpeg_decode_init(AVCodecContext *avctx)
1068{
1069 Mpeg1Context *s = avctx->priv_data;
1070
1071 s->header_state = 0xff;
1072 s->mpeg_enc_ctx_allocated = 0;
1073 s->buffer_size = PICTURE_BUFFER_SIZE;
1074 s->start_code = -1;
1075 s->buf_ptr = s->buffer;
1076 s->mpeg_enc_ctx.picture_number = 0;
1077 return 0;
1078}
1079
1080/* return the 8 bit start code value and update the search
1081 state. Return -1 if no start code found */
1082static int find_start_code(UINT8 **pbuf_ptr, UINT8 *buf_end,
1083 UINT32 *header_state)
1084{
1085 UINT8 *buf_ptr;
1086 unsigned int state, v;
1087 int val;
1088
1089 state = *header_state;
1090 buf_ptr = *pbuf_ptr;
1091 while (buf_ptr < buf_end) {
1092 v = *buf_ptr++;
1093 if (state == 0x000001) {
1094 state = ((state << 8) | v) & 0xffffff;
1095 val = state;
1096 goto found;
1097 }
1098 state = ((state << 8) | v) & 0xffffff;
1099 }
1100 val = -1;
1101 found:
1102 *pbuf_ptr = buf_ptr;
1103 *header_state = state;
1104 return val;
1105}
1106
1107static int mpeg1_decode_picture(AVCodecContext *avctx,
1108 UINT8 *buf, int buf_size)
1109{
1110 Mpeg1Context *s1 = avctx->priv_data;
1111 MpegEncContext *s = &s1->mpeg_enc_ctx;
1112 int ref, f_code;
1113
1114 init_get_bits(&s->gb, buf, buf_size);
1115
1116 ref = get_bits(&s->gb, 10); /* temporal ref */
1117 s->pict_type = get_bits(&s->gb, 3);
1118 dprintf("pict_type=%d\n", s->pict_type);
1119 get_bits(&s->gb, 16);
1120 if (s->pict_type == P_TYPE || s->pict_type == B_TYPE) {
1121 s->full_pel[0] = get_bits(&s->gb, 1);
1122 f_code = get_bits(&s->gb, 3);
1123 if (f_code == 0)
1124 return -1;
1125 s->mpeg_f_code[0][0] = f_code;
1126 s->mpeg_f_code[0][1] = f_code;
1127 }
1128 if (s->pict_type == B_TYPE) {
1129 s->full_pel[1] = get_bits(&s->gb, 1);
1130 f_code = get_bits(&s->gb, 3);
1131 if (f_code == 0)
1132 return -1;
1133 s->mpeg_f_code[1][0] = f_code;
1134 s->mpeg_f_code[1][1] = f_code;
1135 }
1136 s->y_dc_scale = 8;
1137 s->c_dc_scale = 8;
1138 s->first_slice = 1;
1139 return 0;
1140}
1141
1142static void mpeg_decode_sequence_extension(MpegEncContext *s)
1143{
1144 int horiz_size_ext, vert_size_ext;
1145 int bit_rate_ext, vbv_buf_ext, low_delay;
1146 int frame_rate_ext_n, frame_rate_ext_d;
1147
1148 get_bits(&s->gb, 8); /* profil and level */
1149 get_bits(&s->gb, 1); /* progressive_sequence */
1150 get_bits(&s->gb, 2); /* chroma_format */
1151 horiz_size_ext = get_bits(&s->gb, 2);
1152 vert_size_ext = get_bits(&s->gb, 2);
1153 s->width |= (horiz_size_ext << 12);
1154 s->height |= (vert_size_ext << 12);
1155 bit_rate_ext = get_bits(&s->gb, 12); /* XXX: handle it */
1156 s->bit_rate = ((s->bit_rate / 400) | (bit_rate_ext << 12)) * 400;
1157 get_bits(&s->gb, 1); /* marker */
1158 vbv_buf_ext = get_bits(&s->gb, 8);
1159 low_delay = get_bits(&s->gb, 1);
1160 frame_rate_ext_n = get_bits(&s->gb, 2);
1161 frame_rate_ext_d = get_bits(&s->gb, 5);
1162 if (frame_rate_ext_d >= 1)
1163 s->frame_rate = (s->frame_rate * frame_rate_ext_n) / frame_rate_ext_d;
1164 dprintf("sequence extension\n");
1165 s->mpeg2 = 1;
1166}
1167
1168static void mpeg_decode_quant_matrix_extension(MpegEncContext *s)
1169{
1170 int i, v;
1171
1172 if (get_bits(&s->gb, 1)) {
1173 for(i=0;i<64;i++) {
1174 v = get_bits(&s->gb, 8);
1175 s->intra_matrix[i] = v;
1176 s->chroma_intra_matrix[i] = v;
1177 }
1178 }
1179 if (get_bits(&s->gb, 1)) {
1180 for(i=0;i<64;i++) {
1181 v = get_bits(&s->gb, 8);
1182 s->non_intra_matrix[i] = v;
1183 s->chroma_non_intra_matrix[i] = v;
1184 }
1185 }
1186 if (get_bits(&s->gb, 1)) {
1187 for(i=0;i<64;i++) {
1188 v = get_bits(&s->gb, 8);
1189 s->chroma_intra_matrix[i] = v;
1190 }
1191 }
1192 if (get_bits(&s->gb, 1)) {
1193 for(i=0;i<64;i++) {
1194 v = get_bits(&s->gb, 8);
1195 s->chroma_non_intra_matrix[i] = v;
1196 }
1197 }
1198}
1199
1200static void mpeg_decode_picture_coding_extension(MpegEncContext *s)
1201{
1202 s->full_pel[0] = s->full_pel[1] = 0;
1203 s->mpeg_f_code[0][0] = get_bits(&s->gb, 4);
1204 s->mpeg_f_code[0][1] = get_bits(&s->gb, 4);
1205 s->mpeg_f_code[1][0] = get_bits(&s->gb, 4);
1206 s->mpeg_f_code[1][1] = get_bits(&s->gb, 4);
1207 s->intra_dc_precision = get_bits(&s->gb, 2);
1208 s->picture_structure = get_bits(&s->gb, 2);
1209 s->top_field_first = get_bits(&s->gb, 1);
1210 s->frame_pred_frame_dct = get_bits(&s->gb, 1);
1211 s->concealment_motion_vectors = get_bits(&s->gb, 1);
1212 s->q_scale_type = get_bits(&s->gb, 1);
1213 s->intra_vlc_format = get_bits(&s->gb, 1);
1214 s->alternate_scan = get_bits(&s->gb, 1);
1215 s->repeat_first_field = get_bits(&s->gb, 1);
1216 s->chroma_420_type = get_bits(&s->gb, 1);
1217 s->progressive_frame = get_bits(&s->gb, 1);
1218 /* composite display not parsed */
1219 dprintf("dc_preci=%d\n", s->intra_dc_precision);
1220 dprintf("pict_structure=%d\n", s->picture_structure);
1221 dprintf("conceal=%d\n", s->concealment_motion_vectors);
1222 dprintf("intrafmt=%d\n", s->intra_vlc_format);
1223 dprintf("frame_pred_frame_dct=%d\n", s->frame_pred_frame_dct);
1224}
1225
1226static void mpeg_decode_extension(AVCodecContext *avctx,
1227 UINT8 *buf, int buf_size)
1228{
1229 Mpeg1Context *s1 = avctx->priv_data;
1230 MpegEncContext *s = &s1->mpeg_enc_ctx;
1231 int ext_type;
1232
1233 init_get_bits(&s->gb, buf, buf_size);
1234
1235 ext_type = get_bits(&s->gb, 4);
1236 switch(ext_type) {
1237 case 0x1:
1238 /* sequence ext */
1239 mpeg_decode_sequence_extension(s);
1240 break;
1241 case 0x3:
1242 /* quant matrix extension */
1243 mpeg_decode_quant_matrix_extension(s);
1244 break;
1245 case 0x8:
1246 /* picture extension */
1247 mpeg_decode_picture_coding_extension(s);
1248 break;
1249 }
1250}
1251
1252/* return 1 if end of frame */
1253static int mpeg_decode_slice(AVCodecContext *avctx,
1254 AVPicture *pict,
1255 int start_code,
1256 UINT8 *buf, int buf_size)
1257{
1258 Mpeg1Context *s1 = avctx->priv_data;
1259 MpegEncContext *s = &s1->mpeg_enc_ctx;
1260 int ret;
1261 DCTELEM block[6][64];
1262
1263 start_code = (start_code - 1) & 0xff;
1264 if (start_code >= s->mb_height)
1265 return -1;
1266 s->last_dc[0] = 1 << (7 + s->intra_dc_precision);
1267 s->last_dc[1] = s->last_dc[0];
1268 s->last_dc[2] = s->last_dc[0];
1269 memset(s->last_mv, 0, sizeof(s->last_mv));
1270 s->mb_x = -1;
1271 s->mb_y = start_code;
1272 s->mb_incr = 0;
1273
1274 /* start frame decoding */
1275 if (s->first_slice) {
1276 s->first_slice = 0;
1277 MPV_frame_start(s);
1278 }
1279
1280 init_get_bits(&s->gb, buf, buf_size);
1281
1282 s->qscale = get_bits(&s->gb, 5);
1283 /* extra slice info */
1284 while (get_bits(&s->gb, 1) != 0) {
1285 get_bits(&s->gb, 8);
1286 }
1287
1288 for(;;) {
1289 memset(block, 0, sizeof(block));
1290 ret = mpeg_decode_mb(s, block);
1291 dprintf("ret=%d\n", ret);
1292 if (ret < 0)
1293 return -1;
1294 if (ret == 1)
1295 break;
1296 MPV_decode_mb(s, block);
1297 }
1298
1299 /* end of slice reached */
1300 if (s->mb_x == (s->mb_width - 1) &&
1301 s->mb_y == (s->mb_height - 1)) {
1302 /* end of image */
1303 UINT8 **picture;
1304
1305 MPV_frame_end(s);
1306
1307 /* XXX: incorrect reported qscale for mpeg2 */
1308 if (s->pict_type == B_TYPE) {
1309 picture = s->current_picture;
1310 avctx->quality = s->qscale;
1311 } else {
1312 /* latency of 1 frame for I and P frames */
1313 /* XXX: use another variable than picture_number */
1314 if (s->picture_number == 0) {
1315 picture = NULL;
1316 } else {
1317 picture = s->last_picture;
1318 avctx->quality = s->last_qscale;
1319 }
1320 s->last_qscale = s->qscale;
1321 s->picture_number++;
1322 }
1323 if (picture) {
1324 pict->data[0] = picture[0];
1325 pict->data[1] = picture[1];
1326 pict->data[2] = picture[2];
1327 pict->linesize[0] = s->linesize;
1328 pict->linesize[1] = s->linesize / 2;
1329 pict->linesize[2] = s->linesize / 2;
1330 return 1;
1331 } else {
1332 return 0;
1333 }
1334 } else {
1335 return 0;
1336 }
1337}
1338
1339static int mpeg1_decode_sequence(AVCodecContext *avctx,
1340 UINT8 *buf, int buf_size)
1341{
1342 Mpeg1Context *s1 = avctx->priv_data;
1343 MpegEncContext *s = &s1->mpeg_enc_ctx;
1344 int width, height, i, v;
1345
1346 init_get_bits(&s->gb, buf, buf_size);
1347
1348 width = get_bits(&s->gb, 12);
1349 height = get_bits(&s->gb, 12);
1350 get_bits(&s->gb, 4);
1351 s->frame_rate_index = get_bits(&s->gb, 4);
1352 if (s->frame_rate_index == 0)
1353 return -1;
1354 s->bit_rate = get_bits(&s->gb, 18) * 400;
1355 if (get_bits(&s->gb, 1) == 0) /* marker */
1356 return -1;
1357 if (width <= 0 || height <= 0 ||
1358 (width % 2) != 0 || (height % 2) != 0)
1359 return -1;
1360 if (width != s->width ||
1361 height != s->height) {
1362 /* start new mpeg1 context decoding */
1363 s->out_format = FMT_MPEG1;
1364 if (s1->mpeg_enc_ctx_allocated) {
1365 MPV_common_end(s);
1366 }
1367 s->width = width;
1368 s->height = height;
1369 s->has_b_frames = 1;
1370 avctx->width = width;
1371 avctx->height = height;
1372 avctx->frame_rate = frame_rate_tab[s->frame_rate_index];
1373 avctx->bit_rate = s->bit_rate;
1374
1375 if (MPV_common_init(s) < 0)
1376 return -1;
1377 mpeg1_init_vlc(s);
1378 s1->mpeg_enc_ctx_allocated = 1;
1379 }
1380
1381 get_bits(&s->gb, 10); /* vbv_buffer_size */
1382 get_bits(&s->gb, 1);
1383
1384 /* get matrix */
1385 if (get_bits(&s->gb, 1)) {
1386 for(i=0;i<64;i++) {
1387 v = get_bits(&s->gb, 8);
1388 s->intra_matrix[i] = v;
1389 s->chroma_intra_matrix[i] = v;
1390 }
1391 } else {
1392 for(i=0;i<64;i++) {
1393 v = default_intra_matrix[i];
1394 s->intra_matrix[i] = v;
1395 s->chroma_intra_matrix[i] = v;
1396 }
1397 }
1398 if (get_bits(&s->gb, 1)) {
1399 for(i=0;i<64;i++) {
1400 v = get_bits(&s->gb, 8);
1401 s->non_intra_matrix[i] = v;
1402 s->chroma_non_intra_matrix[i] = v;
1403 }
1404 } else {
1405 for(i=0;i<64;i++) {
1406 v = default_non_intra_matrix[i];
1407 s->non_intra_matrix[i] = v;
1408 s->chroma_non_intra_matrix[i] = v;
1409 }
1410 }
1411
1412 /* we set mpeg2 parameters so that it emulates mpeg1 */
1413 s->progressive_sequence = 1;
1414 s->progressive_frame = 1;
1415 s->picture_structure = PICT_FRAME;
1416 s->frame_pred_frame_dct = 1;
1417 s->mpeg2 = 0;
1418 return 0;
1419}
1420
1421/* handle buffering and image synchronisation */
1422static int mpeg_decode_frame(AVCodecContext *avctx,
1423 void *data, int *data_size,
1424 UINT8 *buf, int buf_size)
1425{
1426 Mpeg1Context *s = avctx->priv_data;
1427 UINT8 *buf_end, *buf_ptr, *buf_start;
1428 int len, start_code_found, ret, code, start_code, input_size;
1429 AVPicture *picture = data;
1430
1431 dprintf("fill_buffer\n");
1432
1433 *data_size = 0;
1434 /* special case for last picture */
1435 if (buf_size == 0) {
1436 MpegEncContext *s2 = &s->mpeg_enc_ctx;
1437 if (s2->picture_number > 0) {
1438 picture->data[0] = s2->next_picture[0];
1439 picture->data[1] = s2->next_picture[1];
1440 picture->data[2] = s2->next_picture[2];
1441 picture->linesize[0] = s2->linesize;
1442 picture->linesize[1] = s2->linesize / 2;
1443 picture->linesize[2] = s2->linesize / 2;
1444 *data_size = sizeof(AVPicture);
1445 }
1446 return 0;
1447 }
1448
1449 buf_ptr = buf;
1450 buf_end = buf + buf_size;
1451 while (buf_ptr < buf_end) {
1452 buf_start = buf_ptr;
1453 /* find start next code */
1454 code = find_start_code(&buf_ptr, buf_end, &s->header_state);
1455 if (code >= 0) {
1456 start_code_found = 1;
1457 } else {
1458 start_code_found = 0;
1459 }
1460 /* copy to buffer */
1461 len = buf_ptr - buf_start;
1462 if (len + (s->buf_ptr - s->buffer) > s->buffer_size) {
1463 /* data too big : flush */
1464 s->buf_ptr = s->buffer;
1465 if (start_code_found)
1466 s->start_code = code;
1467 } else {
1468 memcpy(s->buf_ptr, buf_start, len);
1469 s->buf_ptr += len;
1470
1471 if (start_code_found) {
1472 /* prepare data for next start code */
1473 input_size = s->buf_ptr - s->buffer;
1474 start_code = s->start_code;
1475 s->buf_ptr = s->buffer;
1476 s->start_code = code;
1477 switch(start_code) {
1478 case SEQ_START_CODE:
1479 mpeg1_decode_sequence(avctx, s->buffer,
1480 input_size);
1481 break;
1482
1483 case PICTURE_START_CODE:
1484 /* we have a complete image : we try to decompress it */
1485 mpeg1_decode_picture(avctx,
1486 s->buffer, input_size);
1487 break;
1488 case EXT_START_CODE:
1489 mpeg_decode_extension(avctx,
1490 s->buffer, input_size);
1491 break;
1492 default:
1493 if (start_code >= SLICE_MIN_START_CODE &&
1494 start_code <= SLICE_MAX_START_CODE) {
1495 ret = mpeg_decode_slice(avctx, picture,
1496 start_code, s->buffer, input_size);
1497 if (ret == 1) {
1498 /* got a picture: exit */
1499 *data_size = sizeof(AVPicture);
1500 goto the_end;
1501 }
1502 }
1503 break;
1504 }
1505 }
1506 }
1507 }
1508 the_end:
1509 return buf_ptr - buf;
1510}
1511
1512static int mpeg_decode_end(AVCodecContext *avctx)
1513{
1514 Mpeg1Context *s = avctx->priv_data;
1515
1516 if (s->mpeg_enc_ctx_allocated)
1517 MPV_common_end(&s->mpeg_enc_ctx);
1518 return 0;
1519}
1520
1521AVCodec mpeg_decoder = {
1522 "mpegvideo",
1523 CODEC_TYPE_VIDEO,
1524 CODEC_ID_MPEG1VIDEO,
1525 sizeof(Mpeg1Context),
1526 mpeg_decode_init,
1527 NULL,
1528 mpeg_decode_end,
1529 mpeg_decode_frame,
1530};