9b1e271ef5a9e14c03f509321a378004bd9e12ed
[libav.git] / libavformat / avidec.c
1 /*
2 * AVI decoder.
3 * Copyright (c) 2001 Fabrice Bellard.
4 *
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
9 *
10 * This library 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 GNU
13 * Lesser General Public License for more details.
14 *
15 * You should have received a copy of the GNU Lesser General Public
16 * License along with this library; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 */
19 #include "avformat.h"
20 #include "avi.h"
21 #include "dv.h"
22
23 //#define DEBUG
24 //#define DEBUG_SEEK
25
26 typedef struct AVIIndexEntry {
27 unsigned int flags;
28 unsigned int pos;
29 unsigned int cum_len; /* sum of all lengths before this packet */
30 } AVIIndexEntry;
31
32 typedef struct AVIStream {
33 AVIIndexEntry *index_entries;
34 int nb_index_entries;
35 int index_entries_allocated_size;
36 int frame_offset; /* current frame (video) or byte (audio) counter
37 (used to compute the pts) */
38 int scale;
39 int rate;
40 int sample_size; /* audio only data */
41 int start;
42
43 int new_frame_offset; /* temporary storage (used during seek) */
44 int cum_len; /* temporary storage (used during seek) */
45
46 int prefix; ///< normally 'd'<<8 + 'c' or 'w'<<8 + 'b'
47 int prefix_count;
48 } AVIStream;
49
50 typedef struct {
51 int64_t riff_end;
52 int64_t movi_end;
53 offset_t movi_list;
54 int index_loaded;
55 int is_odml;
56 DVDemuxContext* dv_demux;
57 } AVIContext;
58
59 static int avi_load_index(AVFormatContext *s);
60
61 #ifdef DEBUG
62 static void print_tag(const char *str, unsigned int tag, int size)
63 {
64 printf("%s: tag=%c%c%c%c size=0x%x\n",
65 str, tag & 0xff,
66 (tag >> 8) & 0xff,
67 (tag >> 16) & 0xff,
68 (tag >> 24) & 0xff,
69 size);
70 }
71 #endif
72
73 static int get_riff(AVIContext *avi, ByteIOContext *pb)
74 {
75 uint32_t tag;
76 /* check RIFF header */
77 tag = get_le32(pb);
78
79 if (tag != MKTAG('R', 'I', 'F', 'F'))
80 return -1;
81 avi->riff_end = get_le32(pb); /* RIFF chunk size */
82 avi->riff_end += url_ftell(pb); /* RIFF chunk end */
83 tag = get_le32(pb);
84 if (tag != MKTAG('A', 'V', 'I', ' ') && tag != MKTAG('A', 'V', 'I', 'X'))
85 return -1;
86
87 return 0;
88 }
89
90 static int avi_read_header(AVFormatContext *s, AVFormatParameters *ap)
91 {
92 AVIContext *avi = s->priv_data;
93 ByteIOContext *pb = &s->pb;
94 uint32_t tag, tag1, handler;
95 int codec_type, stream_index, frame_period, bit_rate, scale, rate;
96 unsigned int size, nb_frames;
97 int i, n;
98 AVStream *st;
99 AVIStream *ast;
100 int xan_video = 0; /* hack to support Xan A/V */
101
102 if (get_riff(avi, pb) < 0)
103 return -1;
104
105 /* first list tag */
106 stream_index = -1;
107 codec_type = -1;
108 frame_period = 0;
109 for(;;) {
110 if (url_feof(pb))
111 goto fail;
112 tag = get_le32(pb);
113 size = get_le32(pb);
114 #ifdef DEBUG
115 print_tag("tag", tag, size);
116 #endif
117
118 switch(tag) {
119 case MKTAG('L', 'I', 'S', 'T'):
120 /* ignored, except when start of video packets */
121 tag1 = get_le32(pb);
122 #ifdef DEBUG
123 print_tag("list", tag1, 0);
124 #endif
125 if (tag1 == MKTAG('m', 'o', 'v', 'i')) {
126 avi->movi_list = url_ftell(pb) - 4;
127 if(size) avi->movi_end = avi->movi_list + size;
128 else avi->movi_end = url_filesize(url_fileno(pb));
129 #ifdef DEBUG
130 printf("movi end=%Lx\n", avi->movi_end);
131 #endif
132 goto end_of_header;
133 }
134 break;
135 case MKTAG('d', 'm', 'l', 'h'):
136 avi->is_odml = 1;
137 url_fskip(pb, size + (size & 1));
138 break;
139 case MKTAG('a', 'v', 'i', 'h'):
140 /* avi header */
141 /* using frame_period is bad idea */
142 frame_period = get_le32(pb);
143 bit_rate = get_le32(pb) * 8;
144 url_fskip(pb, 4 * 4);
145 n = get_le32(pb);
146 for(i=0;i<n;i++) {
147 AVIStream *ast;
148 st = av_new_stream(s, i);
149 if (!st)
150 goto fail;
151
152 ast = av_mallocz(sizeof(AVIStream));
153 if (!ast)
154 goto fail;
155 st->priv_data = ast;
156 }
157 url_fskip(pb, size - 7 * 4);
158 break;
159 case MKTAG('s', 't', 'r', 'h'):
160 /* stream header */
161 stream_index++;
162 tag1 = get_le32(pb);
163 handler = get_le32(pb); /* codec tag */
164 #ifdef DEBUG
165 print_tag("strh", tag1, -1);
166 #endif
167 switch(tag1) {
168 case MKTAG('i', 'a', 'v', 's'):
169 case MKTAG('i', 'v', 'a', 's'):
170 /*
171 * After some consideration -- I don't think we
172 * have to support anything but DV in a type1 AVIs.
173 */
174 if (s->nb_streams != 1)
175 goto fail;
176
177 if (handler != MKTAG('d', 'v', 's', 'd') &&
178 handler != MKTAG('d', 'v', 'h', 'd') &&
179 handler != MKTAG('d', 'v', 's', 'l'))
180 goto fail;
181
182 av_freep(&s->streams[0]->codec.extradata);
183 av_freep(&s->streams[0]);
184 s->nb_streams = 0;
185 avi->dv_demux = dv_init_demux(s);
186 if (!avi->dv_demux)
187 goto fail;
188 stream_index = s->nb_streams - 1;
189 url_fskip(pb, size - 8);
190 break;
191 case MKTAG('v', 'i', 'd', 's'):
192 codec_type = CODEC_TYPE_VIDEO;
193
194 if (stream_index >= s->nb_streams) {
195 url_fskip(pb, size - 8);
196 break;
197 }
198
199 st = s->streams[stream_index];
200 ast = st->priv_data;
201 st->codec.stream_codec_tag= handler;
202
203 get_le32(pb); /* flags */
204 get_le16(pb); /* priority */
205 get_le16(pb); /* language */
206 get_le32(pb); /* XXX: initial frame ? */
207 scale = get_le32(pb); /* scale */
208 rate = get_le32(pb); /* rate */
209
210 if(scale && rate){
211 }else if(frame_period){
212 rate = 1000000;
213 scale = frame_period;
214 }else{
215 rate = 25;
216 scale = 1;
217 }
218 ast->rate = rate;
219 ast->scale = scale;
220 av_set_pts_info(st, 64, scale, rate);
221 st->codec.frame_rate = rate;
222 st->codec.frame_rate_base = scale;
223 get_le32(pb); /* start */
224 nb_frames = get_le32(pb);
225 st->start_time = 0;
226 st->duration = av_rescale(nb_frames,
227 st->codec.frame_rate_base * AV_TIME_BASE,
228 st->codec.frame_rate);
229 url_fskip(pb, size - 9 * 4);
230 break;
231 case MKTAG('a', 'u', 'd', 's'):
232 {
233 unsigned int length;
234
235 codec_type = CODEC_TYPE_AUDIO;
236
237 if (stream_index >= s->nb_streams) {
238 url_fskip(pb, size - 8);
239 break;
240 }
241 st = s->streams[stream_index];
242 ast = st->priv_data;
243
244 get_le32(pb); /* flags */
245 get_le16(pb); /* priority */
246 get_le16(pb); /* language */
247 get_le32(pb); /* initial frame */
248 ast->scale = get_le32(pb); /* scale */
249 ast->rate = get_le32(pb);
250 av_set_pts_info(st, 64, ast->scale, ast->rate);
251 ast->start= get_le32(pb); /* start */
252 length = get_le32(pb); /* length, in samples or bytes */
253 get_le32(pb); /* buffer size */
254 get_le32(pb); /* quality */
255 ast->sample_size = get_le32(pb); /* sample ssize */
256 //av_log(NULL, AV_LOG_DEBUG, "%d %d %d %d\n", ast->scale, ast->rate, ast->sample_size, ast->start);
257 st->start_time = 0;
258 if (ast->rate != 0)
259 st->duration = (int64_t)length * AV_TIME_BASE / ast->rate;
260 url_fskip(pb, size - 12 * 4);
261 }
262 break;
263 case MKTAG('t', 'x', 't', 's'):
264 //FIXME
265 codec_type = CODEC_TYPE_DATA; //CODEC_TYPE_SUB ? FIXME
266 url_fskip(pb, size - 8);
267 break;
268 default:
269 goto fail;
270 }
271 break;
272 case MKTAG('s', 't', 'r', 'f'):
273 /* stream header */
274 if (stream_index >= s->nb_streams || avi->dv_demux) {
275 url_fskip(pb, size);
276 } else {
277 st = s->streams[stream_index];
278 switch(codec_type) {
279 case CODEC_TYPE_VIDEO:
280 get_le32(pb); /* size */
281 st->codec.width = get_le32(pb);
282 st->codec.height = get_le32(pb);
283 get_le16(pb); /* panes */
284 st->codec.bits_per_sample= get_le16(pb); /* depth */
285 tag1 = get_le32(pb);
286 get_le32(pb); /* ImageSize */
287 get_le32(pb); /* XPelsPerMeter */
288 get_le32(pb); /* YPelsPerMeter */
289 get_le32(pb); /* ClrUsed */
290 get_le32(pb); /* ClrImportant */
291
292 st->codec.extradata_size= size - 10*4;
293 st->codec.extradata= av_malloc(st->codec.extradata_size);
294 get_buffer(pb, st->codec.extradata, st->codec.extradata_size);
295
296 if(st->codec.extradata_size & 1) //FIXME check if the encoder really did this correctly
297 get_byte(pb);
298
299 /* Extract palette from extradata if bpp <= 8 */
300 /* This code assumes that extradata contains only palette */
301 /* This is true for all paletted codecs implemented in ffmpeg */
302 if (st->codec.extradata_size && (st->codec.bits_per_sample <= 8)) {
303 st->codec.palctrl = av_mallocz(sizeof(AVPaletteControl));
304 #ifdef WORDS_BIGENDIAN
305 for (i = 0; i < FFMIN(st->codec.extradata_size, AVPALETTE_SIZE)/4; i++)
306 st->codec.palctrl->palette[i] = bswap_32(((uint32_t*)st->codec.extradata)[i]);
307 #else
308 memcpy(st->codec.palctrl->palette, st->codec.extradata,
309 FFMIN(st->codec.extradata_size, AVPALETTE_SIZE));
310 #endif
311 st->codec.palctrl->palette_changed = 1;
312 }
313
314 #ifdef DEBUG
315 print_tag("video", tag1, 0);
316 #endif
317 st->codec.codec_type = CODEC_TYPE_VIDEO;
318 st->codec.codec_tag = tag1;
319 st->codec.codec_id = codec_get_id(codec_bmp_tags, tag1);
320 if (st->codec.codec_id == CODEC_ID_XAN_WC4)
321 xan_video = 1;
322 // url_fskip(pb, size - 5 * 4);
323 break;
324 case CODEC_TYPE_AUDIO:
325 get_wav_header(pb, &st->codec, size);
326 if (size%2) /* 2-aligned (fix for Stargate SG-1 - 3x18 - Shades of Grey.avi) */
327 url_fskip(pb, 1);
328 /* special case time: To support Xan DPCM, hardcode
329 * the format if Xxan is the video codec */
330 st->need_parsing = 1;
331 /* force parsing as several audio frames can be in
332 one packet */
333 if (xan_video)
334 st->codec.codec_id = CODEC_ID_XAN_DPCM;
335 break;
336 default:
337 st->codec.codec_type = CODEC_TYPE_DATA;
338 st->codec.codec_id= CODEC_ID_NONE;
339 st->codec.codec_tag= 0;
340 url_fskip(pb, size);
341 break;
342 }
343 }
344 break;
345 default:
346 /* skip tag */
347 size += (size & 1);
348 url_fskip(pb, size);
349 break;
350 }
351 }
352 end_of_header:
353 /* check stream number */
354 if (stream_index != s->nb_streams - 1) {
355 fail:
356 for(i=0;i<s->nb_streams;i++) {
357 av_freep(&s->streams[i]->codec.extradata);
358 av_freep(&s->streams[i]);
359 }
360 return -1;
361 }
362
363 assert(!avi->index_loaded);
364 avi_load_index(s);
365 avi->index_loaded = 1;
366
367 return 0;
368 }
369
370 static int avi_read_packet(AVFormatContext *s, AVPacket *pkt)
371 {
372 AVIContext *avi = s->priv_data;
373 ByteIOContext *pb = &s->pb;
374 int n, d[8], size;
375 offset_t i;
376 void* dstr;
377
378 memset(d, -1, sizeof(int)*8);
379
380 if (avi->dv_demux) {
381 size = dv_get_packet(avi->dv_demux, pkt);
382 if (size >= 0)
383 return size;
384 }
385
386 for(i=url_ftell(pb); !url_feof(pb); i++) {
387 int j;
388
389 if (i >= avi->movi_end) {
390 if (avi->is_odml) {
391 url_fskip(pb, avi->riff_end - i);
392 avi->riff_end = avi->movi_end = url_filesize(url_fileno(pb));
393 } else
394 break;
395 }
396
397 for(j=0; j<7; j++)
398 d[j]= d[j+1];
399 d[7]= get_byte(pb);
400
401 size= d[4] + (d[5]<<8) + (d[6]<<16) + (d[7]<<24);
402
403 if( d[2] >= '0' && d[2] <= '9'
404 && d[3] >= '0' && d[3] <= '9'){
405 n= (d[2] - '0') * 10 + (d[3] - '0');
406 }else{
407 n= 100; //invalid stream id
408 }
409 //av_log(NULL, AV_LOG_DEBUG, "%X %X %X %X %X %X %X %X %lld %d %d\n", d[0], d[1], d[2], d[3], d[4], d[5], d[6], d[7], i, size, n);
410 if(i + size > avi->movi_end || d[0]<0)
411 continue;
412
413 //parse ix##
414 if( (d[0] == 'i' && d[1] == 'x' && n < s->nb_streams)
415 //parse JUNK
416 ||(d[0] == 'J' && d[1] == 'U' && d[2] == 'N' && d[3] == 'K')){
417 url_fskip(pb, size);
418 i+= size;
419 memset(d, -1, sizeof(int)*8);
420 //av_log(NULL, AV_LOG_DEBUG, "SKIP\n");
421 continue;
422 }
423
424 if( d[0] >= '0' && d[0] <= '9'
425 && d[1] >= '0' && d[1] <= '9'){
426 n= (d[0] - '0') * 10 + (d[1] - '0');
427 }else{
428 n= 100; //invalid stream id
429 }
430
431 //parse ##dc/##wb
432 if(n < s->nb_streams){
433 AVStream *st;
434 AVIStream *ast;
435 st = s->streams[n];
436 ast = st->priv_data;
437
438 if( (ast->prefix_count<5 && d[2]<128 && d[3]<128) ||
439 d[2]*256+d[3] == ast->prefix /*||
440 (d[2] == 'd' && d[3] == 'c') ||
441 (d[2] == 'w' && d[3] == 'b')*/) {
442
443 //av_log(NULL, AV_LOG_DEBUG, "OK\n");
444 if(d[2]*256+d[3] == ast->prefix)
445 ast->prefix_count++;
446 else{
447 ast->prefix= d[2]*256+d[3];
448 ast->prefix_count= 0;
449 }
450
451 av_new_packet(pkt, size);
452 get_buffer(pb, pkt->data, size);
453 if (size & 1) {
454 get_byte(pb);
455 size++;
456 }
457
458 if (avi->dv_demux) {
459 dstr = pkt->destruct;
460 size = dv_produce_packet(avi->dv_demux, pkt,
461 pkt->data, pkt->size);
462 pkt->destruct = dstr;
463 pkt->flags |= PKT_FLAG_KEY;
464 } else {
465 /* XXX: how to handle B frames in avi ? */
466 pkt->dts = ast->frame_offset;
467 // pkt->dts += ast->start;
468 if(ast->sample_size)
469 pkt->dts /= ast->sample_size;
470 //av_log(NULL, AV_LOG_DEBUG, "dts:%Ld offset:%d %d/%d smpl_siz:%d base:%d st:%d size:%d\n", pkt->dts, ast->frame_offset, ast->scale, ast->rate, ast->sample_size, AV_TIME_BASE, n, size);
471 pkt->stream_index = n;
472 /* FIXME: We really should read index for that */
473 if (st->codec.codec_type == CODEC_TYPE_VIDEO) {
474 if (ast->frame_offset < ast->nb_index_entries) {
475 if (ast->index_entries[ast->frame_offset].flags & AVIIF_INDEX)
476 pkt->flags |= PKT_FLAG_KEY;
477 } else {
478 /* if no index, better to say that all frames
479 are key frames */
480 pkt->flags |= PKT_FLAG_KEY;
481 }
482 } else {
483 pkt->flags |= PKT_FLAG_KEY;
484 }
485 if(ast->sample_size)
486 ast->frame_offset += pkt->size;
487 else
488 ast->frame_offset++;
489 }
490 return size;
491 }
492 }
493 }
494
495 return -1;
496 }
497
498 /* XXX: we make the implicit supposition that the position are sorted
499 for each stream */
500 static int avi_read_idx1(AVFormatContext *s, int size)
501 {
502 ByteIOContext *pb = &s->pb;
503 int nb_index_entries, i;
504 AVStream *st;
505 AVIStream *ast;
506 AVIIndexEntry *ie, *entries;
507 unsigned int index, tag, flags, pos, len;
508
509 nb_index_entries = size / 16;
510 if (nb_index_entries <= 0)
511 return -1;
512
513 /* read the entries and sort them in each stream component */
514 for(i = 0; i < nb_index_entries; i++) {
515 tag = get_le32(pb);
516 flags = get_le32(pb);
517 pos = get_le32(pb);
518 len = get_le32(pb);
519 #if defined(DEBUG_SEEK) && 0
520 printf("%d: tag=0x%x flags=0x%x pos=0x%x len=%d\n",
521 i, tag, flags, pos, len);
522 #endif
523 index = ((tag & 0xff) - '0') * 10;
524 index += ((tag >> 8) & 0xff) - '0';
525 if (index >= s->nb_streams)
526 continue;
527 st = s->streams[index];
528 ast = st->priv_data;
529
530 entries = av_fast_realloc(ast->index_entries,
531 &ast->index_entries_allocated_size,
532 (ast->nb_index_entries + 1) *
533 sizeof(AVIIndexEntry));
534 if (entries) {
535 ast->index_entries = entries;
536 ie = &entries[ast->nb_index_entries++];
537 ie->flags = flags;
538 ie->pos = pos;
539 ie->cum_len = ast->cum_len;
540 ast->cum_len += len;
541 }
542 }
543 return 0;
544 }
545
546 static int avi_load_index(AVFormatContext *s)
547 {
548 AVIContext *avi = s->priv_data;
549 ByteIOContext *pb = &s->pb;
550 uint32_t tag, size;
551 offset_t pos= url_ftell(pb);
552
553 url_fseek(pb, avi->movi_end, SEEK_SET);
554 #ifdef DEBUG_SEEK
555 printf("movi_end=0x%llx\n", avi->movi_end);
556 #endif
557 for(;;) {
558 if (url_feof(pb))
559 break;
560 tag = get_le32(pb);
561 size = get_le32(pb);
562 #ifdef DEBUG_SEEK
563 printf("tag=%c%c%c%c size=0x%x\n",
564 tag & 0xff,
565 (tag >> 8) & 0xff,
566 (tag >> 16) & 0xff,
567 (tag >> 24) & 0xff,
568 size);
569 #endif
570 switch(tag) {
571 case MKTAG('i', 'd', 'x', '1'):
572 if (avi_read_idx1(s, size) < 0)
573 goto skip;
574 else
575 goto the_end;
576 break;
577 default:
578 skip:
579 size += (size & 1);
580 url_fskip(pb, size);
581 break;
582 }
583 }
584 the_end:
585 url_fseek(pb, pos, SEEK_SET);
586 return 0;
587 }
588
589 /* return the index entry whose position is immediately >= 'wanted_pos' */
590 static int locate_frame_in_index(AVIIndexEntry *entries,
591 int nb_entries, int wanted_pos)
592 {
593 int a, b, m, pos;
594
595 a = 0;
596 b = nb_entries - 1;
597 while (a <= b) {
598 m = (a + b) >> 1;
599 pos = entries[m].pos;
600 if (pos == wanted_pos)
601 goto found;
602 else if (pos > wanted_pos) {
603 b = m - 1;
604 } else {
605 a = m + 1;
606 }
607 }
608 m = a;
609 if (m > 0)
610 m--;
611 found:
612 return m;
613 }
614
615 static int avi_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp)
616 {
617 AVIContext *avi = s->priv_data;
618 AVStream *st;
619 AVIStream *ast;
620 int frame_number, i;
621 int64_t pos;
622
623 if (!avi->index_loaded) {
624 /* we only load the index on demand */
625 avi_load_index(s);
626 avi->index_loaded = 1;
627 }
628 if (stream_index < 0) {
629 for(i = 0; i < s->nb_streams; i++) {
630 st = s->streams[i];
631 if (st->codec.codec_type == CODEC_TYPE_VIDEO)
632 goto found;
633 }
634 return -1;
635 found:
636 stream_index = i;
637 }
638
639 st = s->streams[stream_index];
640 if (st->codec.codec_type != CODEC_TYPE_VIDEO)
641 return -1;
642 ast = st->priv_data;
643 /* compute the frame number */
644 frame_number = timestamp;
645 #ifdef DEBUG_SEEK
646 printf("timestamp=%0.3f nb_indexes=%d frame_number=%d\n",
647 (double)timestamp / AV_TIME_BASE,
648 ast->nb_index_entries, frame_number);
649 #endif
650 /* find a closest key frame before */
651 if (frame_number >= ast->nb_index_entries)
652 return -1;
653 while (frame_number >= 0 &&
654 !(ast->index_entries[frame_number].flags & AVIIF_INDEX))
655 frame_number--;
656 if (frame_number < 0)
657 return -1;
658 ast->new_frame_offset = frame_number;
659
660 /* find the position */
661 pos = ast->index_entries[frame_number].pos;
662
663 #ifdef DEBUG_SEEK
664 printf("key_frame_number=%d pos=0x%llx\n",
665 frame_number, pos);
666 #endif
667
668 /* update the frame counters for all the other stream by looking
669 at the positions just after the one found */
670 for(i = 0; i < s->nb_streams; i++) {
671 int j;
672 if (i != stream_index) {
673 st = s->streams[i];
674 ast = st->priv_data;
675 if (ast->nb_index_entries <= 0)
676 return -1;
677 j = locate_frame_in_index(ast->index_entries,
678 ast->nb_index_entries,
679 pos);
680 /* get next frame */
681 if ((j + 1) < ast->nb_index_entries)
682 j++;
683 /* extract the current frame number */
684 if (ast->sample_size==0)
685 ast->new_frame_offset = j;
686 else
687 ast->new_frame_offset = ast->index_entries[j].cum_len;
688 }
689 }
690
691 /* everything is OK now. We can update the frame offsets */
692 for(i = 0; i < s->nb_streams; i++) {
693 st = s->streams[i];
694 ast = st->priv_data;
695 ast->frame_offset = ast->new_frame_offset;
696 #ifdef DEBUG_SEEK
697 printf("%d: frame_offset=%d\n", i,
698 ast->frame_offset);
699 #endif
700 }
701 /* do the seek */
702 pos += avi->movi_list;
703 url_fseek(&s->pb, pos, SEEK_SET);
704 return 0;
705 }
706
707 static int avi_read_close(AVFormatContext *s)
708 {
709 int i;
710 AVIContext *avi = s->priv_data;
711
712 for(i=0;i<s->nb_streams;i++) {
713 AVStream *st = s->streams[i];
714 AVIStream *ast = st->priv_data;
715 if(ast){
716 av_free(ast->index_entries);
717 av_free(ast);
718 }
719 av_free(st->codec.extradata);
720 av_free(st->codec.palctrl);
721 }
722
723 if (avi->dv_demux)
724 av_free(avi->dv_demux);
725
726 return 0;
727 }
728
729 static int avi_probe(AVProbeData *p)
730 {
731 /* check file header */
732 if (p->buf_size <= 32)
733 return 0;
734 if (p->buf[0] == 'R' && p->buf[1] == 'I' &&
735 p->buf[2] == 'F' && p->buf[3] == 'F' &&
736 p->buf[8] == 'A' && p->buf[9] == 'V' &&
737 p->buf[10] == 'I' && p->buf[11] == ' ')
738 return AVPROBE_SCORE_MAX;
739 else
740 return 0;
741 }
742
743 static AVInputFormat avi_iformat = {
744 "avi",
745 "avi format",
746 sizeof(AVIContext),
747 avi_probe,
748 avi_read_header,
749 avi_read_packet,
750 avi_read_close,
751 avi_read_seek,
752 };
753
754 int avidec_init(void)
755 {
756 av_register_input_format(&avi_iformat);
757 return 0;
758 }