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ffmpeg / libavformat / avidec.c @ b4aea108

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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
                ast = s->streams[0]->priv_data;
183
                av_freep(&s->streams[0]->codec.extradata);
184
                av_freep(&s->streams[0]);
185
                s->nb_streams = 0;
186
                avi->dv_demux = dv_init_demux(s);
187
                if (!avi->dv_demux)
188
                    goto fail;
189
                s->streams[0]->priv_data = ast;
190
                url_fskip(pb, 3 * 4);
191
                ast->scale = get_le32(pb);
192
                ast->rate = get_le32(pb);
193
                stream_index = s->nb_streams - 1;
194
                url_fskip(pb, size - 7*4);
195
                break;
196
            case MKTAG('v', 'i', 'd', 's'):
197
                codec_type = CODEC_TYPE_VIDEO;
198

    
199
                if (stream_index >= s->nb_streams) {
200
                    url_fskip(pb, size - 8);
201
                    break;
202
                } 
203

    
204
                st = s->streams[stream_index];
205
                ast = st->priv_data;
206
                st->codec.stream_codec_tag= handler;
207
                
208
                get_le32(pb); /* flags */
209
                get_le16(pb); /* priority */
210
                get_le16(pb); /* language */
211
                get_le32(pb); /* XXX: initial frame ? */
212
                scale = get_le32(pb); /* scale */
213
                rate = get_le32(pb); /* rate */
214

    
215
                if(scale && rate){
216
                }else if(frame_period){
217
                    rate = 1000000;
218
                    scale = frame_period;
219
                }else{
220
                    rate = 25;
221
                    scale = 1;
222
                }
223
                ast->rate = rate;
224
                ast->scale = scale;
225
                av_set_pts_info(st, 64, scale, rate);
226
                st->codec.frame_rate = rate;
227
                st->codec.frame_rate_base = scale;
228
                get_le32(pb); /* start */
229
                nb_frames = get_le32(pb);
230
                st->start_time = 0;
231
                st->duration = av_rescale(nb_frames,
232
                    st->codec.frame_rate_base * AV_TIME_BASE,
233
                    st->codec.frame_rate);
234
                url_fskip(pb, size - 9 * 4);
235
                break;
236
            case MKTAG('a', 'u', 'd', 's'):
237
                {
238
                    unsigned int length;
239

    
240
                    codec_type = CODEC_TYPE_AUDIO;
241

    
242
                    if (stream_index >= s->nb_streams) {
243
                        url_fskip(pb, size - 8);
244
                        break;
245
                    } 
246
                    st = s->streams[stream_index];
247
                    ast = st->priv_data;
248
                    
249
                    get_le32(pb); /* flags */
250
                    get_le16(pb); /* priority */
251
                    get_le16(pb); /* language */
252
                    get_le32(pb); /* initial frame */
253
                    ast->scale = get_le32(pb); /* scale */
254
                    ast->rate = get_le32(pb);
255
                    if(!ast->rate)
256
                        ast->rate= 1; //wrong but better then 1/0
257
                    if(!ast->scale)
258
                        ast->scale= 1; //wrong but better then 1/0
259
                    av_set_pts_info(st, 64, ast->scale, ast->rate);
260
                    ast->start= get_le32(pb); /* start */
261
                    length = get_le32(pb); /* length, in samples or bytes */
262
                    get_le32(pb); /* buffer size */
263
                    get_le32(pb); /* quality */
264
                    ast->sample_size = get_le32(pb); /* sample ssize */
265
//av_log(NULL, AV_LOG_DEBUG, "%d %d %d %d\n", ast->scale, ast->rate, ast->sample_size, ast->start);
266
                    st->start_time = 0;
267
                    if (ast->rate != 0)
268
                        st->duration = (int64_t)length * AV_TIME_BASE / ast->rate;
269
                    url_fskip(pb, size - 12 * 4);
270
                }
271
                break;
272
            case MKTAG('t', 'x', 't', 's'):
273
                //FIXME 
274
                codec_type = CODEC_TYPE_DATA; //CODEC_TYPE_SUB ?  FIXME
275
                url_fskip(pb, size - 8);
276
                break;
277
            case MKTAG('p', 'a', 'd', 's'):
278
                codec_type = CODEC_TYPE_UNKNOWN;
279
                url_fskip(pb, size - 8);
280
                stream_index--;
281
                break;
282
            default:
283
                av_log(s, AV_LOG_ERROR, "unknown stream type %X\n", tag1);
284
                goto fail;
285
            }
286
            break;
287
        case MKTAG('s', 't', 'r', 'f'):
288
            /* stream header */
289
            if (stream_index >= s->nb_streams || avi->dv_demux) {
290
                url_fskip(pb, size);
291
            } else {
292
                st = s->streams[stream_index];
293
                switch(codec_type) {
294
                case CODEC_TYPE_VIDEO:
295
                    get_le32(pb); /* size */
296
                    st->codec.width = get_le32(pb);
297
                    st->codec.height = get_le32(pb);
298
                    get_le16(pb); /* panes */
299
                    st->codec.bits_per_sample= get_le16(pb); /* depth */
300
                    tag1 = get_le32(pb);
301
                    get_le32(pb); /* ImageSize */
302
                    get_le32(pb); /* XPelsPerMeter */
303
                    get_le32(pb); /* YPelsPerMeter */
304
                    get_le32(pb); /* ClrUsed */
305
                    get_le32(pb); /* ClrImportant */
306

    
307
                 if(size > 10*4 && size<(1<<30)){
308
                    st->codec.extradata_size= size - 10*4;
309
                    st->codec.extradata= av_malloc(st->codec.extradata_size + FF_INPUT_BUFFER_PADDING_SIZE);
310
                    get_buffer(pb, st->codec.extradata, st->codec.extradata_size);
311
                 }
312
                    
313
                    if(st->codec.extradata_size & 1) //FIXME check if the encoder really did this correctly
314
                        get_byte(pb);
315

    
316
                    /* Extract palette from extradata if bpp <= 8 */
317
                    /* This code assumes that extradata contains only palette */
318
                    /* This is true for all paletted codecs implemented in ffmpeg */
319
                    if (st->codec.extradata_size && (st->codec.bits_per_sample <= 8)) {
320
                        st->codec.palctrl = av_mallocz(sizeof(AVPaletteControl));
321
#ifdef WORDS_BIGENDIAN
322
                        for (i = 0; i < FFMIN(st->codec.extradata_size, AVPALETTE_SIZE)/4; i++)
323
                            st->codec.palctrl->palette[i] = bswap_32(((uint32_t*)st->codec.extradata)[i]);
324
#else
325
                        memcpy(st->codec.palctrl->palette, st->codec.extradata,
326
                               FFMIN(st->codec.extradata_size, AVPALETTE_SIZE));
327
#endif
328
                        st->codec.palctrl->palette_changed = 1;
329
                    }
330

    
331
#ifdef DEBUG
332
                    print_tag("video", tag1, 0);
333
#endif
334
                    st->codec.codec_type = CODEC_TYPE_VIDEO;
335
                    st->codec.codec_tag = tag1;
336
                    st->codec.codec_id = codec_get_id(codec_bmp_tags, tag1);
337
                    if (st->codec.codec_id == CODEC_ID_XAN_WC4)
338
                        xan_video = 1;
339
//                    url_fskip(pb, size - 5 * 4);
340
                    break;
341
                case CODEC_TYPE_AUDIO:
342
                    get_wav_header(pb, &st->codec, size);
343
                    if (size%2) /* 2-aligned (fix for Stargate SG-1 - 3x18 - Shades of Grey.avi) */
344
                        url_fskip(pb, 1);
345
                    /* special case time: To support Xan DPCM, hardcode
346
                     * the format if Xxan is the video codec */
347
                    st->need_parsing = 1;
348
                    /* force parsing as several audio frames can be in
349
                       one packet */
350
                    if (xan_video)
351
                        st->codec.codec_id = CODEC_ID_XAN_DPCM;
352
                    break;
353
                default:
354
                    st->codec.codec_type = CODEC_TYPE_DATA;
355
                    st->codec.codec_id= CODEC_ID_NONE;
356
                    st->codec.codec_tag= 0;
357
                    url_fskip(pb, size);
358
                    break;
359
                }
360
            }
361
            break;
362
        default:
363
            /* skip tag */
364
            size += (size & 1);
365
            url_fskip(pb, size);
366
            break;
367
        }
368
    }
369
 end_of_header:
370
    /* check stream number */
371
    if (stream_index != s->nb_streams - 1) {
372
    fail:
373
        for(i=0;i<s->nb_streams;i++) {
374
            av_freep(&s->streams[i]->codec.extradata);
375
            av_freep(&s->streams[i]);
376
        }
377
        return -1;
378
    }
379

    
380
    assert(!avi->index_loaded);
381
    avi_load_index(s);
382
    avi->index_loaded = 1;
383
 
384
    return 0;
385
}
386

    
387
static int avi_read_packet(AVFormatContext *s, AVPacket *pkt)
388
{
389
    AVIContext *avi = s->priv_data;
390
    ByteIOContext *pb = &s->pb;
391
    int n, d[8], size;
392
    offset_t i, sync;
393
    void* dstr;
394
   
395
    if (avi->dv_demux) {
396
        size = dv_get_packet(avi->dv_demux, pkt);
397
        if (size >= 0)
398
            return size;
399
    }
400

    
401
resync:
402
    memset(d, -1, sizeof(int)*8);
403
    for(i=sync=url_ftell(pb); !url_feof(pb); i++) {
404
        int j;
405

    
406
        if (i >= avi->movi_end) {
407
            if (avi->is_odml) {
408
                url_fskip(pb, avi->riff_end - i);
409
                avi->riff_end = avi->movi_end = url_filesize(url_fileno(pb));
410
            } else
411
                break;
412
        }
413

    
414
        for(j=0; j<7; j++)
415
            d[j]= d[j+1];
416
        d[7]= get_byte(pb);
417
        
418
        size= d[4] + (d[5]<<8) + (d[6]<<16) + (d[7]<<24);
419
        
420
        if(    d[2] >= '0' && d[2] <= '9'
421
            && d[3] >= '0' && d[3] <= '9'){
422
            n= (d[2] - '0') * 10 + (d[3] - '0');
423
        }else{
424
            n= 100; //invalid stream id
425
        }
426
//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);
427
        if(i + size > avi->movi_end || d[0]<0)
428
            continue;
429
        
430
        //parse ix##
431
        if(  (d[0] == 'i' && d[1] == 'x' && n < s->nb_streams)
432
        //parse JUNK
433
           ||(d[0] == 'J' && d[1] == 'U' && d[2] == 'N' && d[3] == 'K')){
434
            url_fskip(pb, size);
435
//av_log(NULL, AV_LOG_DEBUG, "SKIP\n");
436
            goto resync;
437
        }
438

    
439
        if(    d[0] >= '0' && d[0] <= '9'
440
            && d[1] >= '0' && d[1] <= '9'){
441
            n= (d[0] - '0') * 10 + (d[1] - '0');
442
        }else{
443
            n= 100; //invalid stream id
444
        }
445
        
446
        //parse ##dc/##wb
447
        if(n < s->nb_streams){
448
          AVStream *st;
449
          AVIStream *ast;
450
          st = s->streams[n];
451
          ast = st->priv_data;
452
          
453
          if(st->discard){
454
                url_fskip(pb, size);
455
                goto resync;
456
          }
457

    
458
          if(   ((ast->prefix_count<5 || sync+9 > i) && d[2]<128 && d[3]<128) || 
459
                d[2]*256+d[3] == ast->prefix /*||
460
                (d[2] == 'd' && d[3] == 'c') || 
461
                (d[2] == 'w' && d[3] == 'b')*/) {
462

    
463
//av_log(NULL, AV_LOG_DEBUG, "OK\n");
464
            if(d[2]*256+d[3] == ast->prefix)
465
                ast->prefix_count++;
466
            else{
467
                ast->prefix= d[2]*256+d[3];
468
                ast->prefix_count= 0;
469
            }
470

    
471
            av_new_packet(pkt, size);
472
            get_buffer(pb, pkt->data, size);
473
            if (size & 1) {
474
                get_byte(pb);
475
                size++;
476
            }
477
        
478
            if (avi->dv_demux) {
479
                dstr = pkt->destruct;
480
                size = dv_produce_packet(avi->dv_demux, pkt,
481
                                         pkt->data, pkt->size);
482
                pkt->destruct = dstr;
483
                pkt->flags |= PKT_FLAG_KEY;
484
            } else {
485
                /* XXX: how to handle B frames in avi ? */
486
                pkt->dts = ast->frame_offset;
487
//                pkt->dts += ast->start;
488
                if(ast->sample_size)
489
                    pkt->dts /= ast->sample_size;
490
//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);
491
                pkt->stream_index = n;
492
                /* FIXME: We really should read index for that */
493
                if (st->codec.codec_type == CODEC_TYPE_VIDEO) {
494
                    if (ast->frame_offset < ast->nb_index_entries) {
495
                        if (ast->index_entries[ast->frame_offset].flags & AVIIF_INDEX)
496
                            pkt->flags |= PKT_FLAG_KEY; 
497
                    } else {
498
                        /* if no index, better to say that all frames
499
                           are key frames */
500
                        pkt->flags |= PKT_FLAG_KEY;
501
                    }
502
                } else {
503
                    pkt->flags |= PKT_FLAG_KEY; 
504
                }
505
                if(ast->sample_size)
506
                    ast->frame_offset += pkt->size;
507
                else
508
                    ast->frame_offset++;
509
            }
510
            return size;
511
          }
512
        }
513
        /* palette changed chunk */
514
        if (   d[0] >= '0' && d[0] <= '9'
515
            && d[1] >= '0' && d[1] <= '9'
516
            && ((d[2] == 'p' && d[3] == 'c'))
517
            && n < s->nb_streams && i + size <= avi->movi_end) {
518

    
519
            AVStream *st;
520
            int first, clr, flags, k, p;
521

    
522
            st = s->streams[n];
523

    
524
            first = get_byte(pb);
525
            clr = get_byte(pb);
526
            if(!clr) /* all 256 colors used */
527
                clr = 256;
528
            flags = get_le16(pb);
529
            p = 4;
530
            for (k = first; k < clr + first; k++) {
531
                int r, g, b;
532
                r = get_byte(pb);
533
                g = get_byte(pb);
534
                b = get_byte(pb);
535
                    get_byte(pb);
536
                st->codec.palctrl->palette[k] = b + (g << 8) + (r << 16);
537
            }
538
            st->codec.palctrl->palette_changed = 1;
539
            goto resync;
540
        }
541

    
542
    }
543

    
544
    return -1;
545
}
546

    
547
/* XXX: we make the implicit supposition that the position are sorted
548
   for each stream */
549
static int avi_read_idx1(AVFormatContext *s, int size)
550
{
551
    ByteIOContext *pb = &s->pb;
552
    int nb_index_entries, i;
553
    AVStream *st;
554
    AVIStream *ast;
555
    AVIIndexEntry *ie, *entries;
556
    unsigned int index, tag, flags, pos, len;
557
    
558
    nb_index_entries = size / 16;
559
    if (nb_index_entries <= 0)
560
        return -1;
561
    if(nb_index_entries + 1 >= UINT_MAX / sizeof(AVIIndexEntry))
562
        return -1;
563

    
564
    /* read the entries and sort them in each stream component */
565
    for(i = 0; i < nb_index_entries; i++) {
566
        tag = get_le32(pb);
567
        flags = get_le32(pb);
568
        pos = get_le32(pb);
569
        len = get_le32(pb);
570
#if defined(DEBUG_SEEK) && 0
571
        printf("%d: tag=0x%x flags=0x%x pos=0x%x len=%d\n", 
572
               i, tag, flags, pos, len);
573
#endif
574
        index = ((tag & 0xff) - '0') * 10;
575
        index += ((tag >> 8) & 0xff) - '0';
576
        if (index >= s->nb_streams)
577
            continue;
578
        st = s->streams[index];
579
        ast = st->priv_data;
580
        
581
        entries = av_fast_realloc(ast->index_entries,
582
                                  &ast->index_entries_allocated_size,
583
                                  (ast->nb_index_entries + 1) * 
584
                                  sizeof(AVIIndexEntry));
585
        if (entries) {
586
            ast->index_entries = entries;
587
            ie = &entries[ast->nb_index_entries++];
588
            ie->flags = flags;
589
            ie->pos = pos;
590
            ie->cum_len = ast->cum_len;
591
            ast->cum_len += len;
592
        }
593
    }
594
    return 0;
595
}
596

    
597
static int avi_load_index(AVFormatContext *s)
598
{
599
    AVIContext *avi = s->priv_data;
600
    ByteIOContext *pb = &s->pb;
601
    uint32_t tag, size;
602
    offset_t pos= url_ftell(pb);
603
    
604
    url_fseek(pb, avi->movi_end, SEEK_SET);
605
#ifdef DEBUG_SEEK
606
    printf("movi_end=0x%llx\n", avi->movi_end);
607
#endif
608
    for(;;) {
609
        if (url_feof(pb))
610
            break;
611
        tag = get_le32(pb);
612
        size = get_le32(pb);
613
#ifdef DEBUG_SEEK
614
        printf("tag=%c%c%c%c size=0x%x\n",
615
               tag & 0xff,
616
               (tag >> 8) & 0xff,
617
               (tag >> 16) & 0xff,
618
               (tag >> 24) & 0xff,
619
               size);
620
#endif
621
        switch(tag) {
622
        case MKTAG('i', 'd', 'x', '1'):
623
            if (avi_read_idx1(s, size) < 0)
624
                goto skip;
625
            else
626
                goto the_end;
627
            break;
628
        default:
629
        skip:
630
            size += (size & 1);
631
            url_fskip(pb, size);
632
            break;
633
        }
634
    }
635
 the_end:
636
    url_fseek(pb, pos, SEEK_SET);
637
    return 0;
638
}
639

    
640
/* return the index entry whose position is immediately >= 'wanted_pos' */
641
static int locate_frame_in_index(AVIIndexEntry *entries, 
642
                                 int nb_entries, int wanted_pos)
643
{
644
    int a, b, m, pos;
645
    
646
    a = 0;
647
    b = nb_entries - 1;
648
    while (a <= b) {
649
        m = (a + b) >> 1;
650
        pos = entries[m].pos;
651
        if (pos == wanted_pos)
652
            goto found;
653
        else if (pos > wanted_pos) {
654
            b = m - 1;
655
        } else {
656
            a = m + 1;
657
        }
658
    }
659
    m = a;
660
    if (m > 0)
661
        m--;
662
 found:
663
    return m;
664
}
665

    
666
static int avi_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
667
{
668
    AVIContext *avi = s->priv_data;
669
    AVStream *st;
670
    AVIStream *ast;
671
    int frame_number, i;
672
    int64_t pos;
673

    
674
    if (!avi->index_loaded) {
675
        /* we only load the index on demand */
676
        avi_load_index(s);
677
        avi->index_loaded = 1;
678
    }
679
    if (stream_index < 0) {
680
        for(i = 0; i < s->nb_streams; i++) {
681
            st = s->streams[i];
682
            if (st->codec.codec_type == CODEC_TYPE_VIDEO)
683
                goto found;
684
        }
685
        return -1;
686
    found:
687
        stream_index = i;
688
    }
689

    
690
    st = s->streams[stream_index];
691
    if (st->codec.codec_type != CODEC_TYPE_VIDEO)
692
        return -1;
693
    ast = st->priv_data;
694
    /* compute the frame number */
695
    frame_number = timestamp;
696
#ifdef DEBUG_SEEK
697
    printf("timestamp=%0.3f nb_indexes=%d frame_number=%d\n", 
698
           (double)timestamp / AV_TIME_BASE,
699
           ast->nb_index_entries, frame_number);
700
#endif
701
    /* find a closest key frame before */
702
    if (frame_number >= ast->nb_index_entries)
703
        return -1;
704
    while (frame_number >= 0 &&
705
           !(ast->index_entries[frame_number].flags & AVIIF_INDEX))
706
        frame_number--;
707
    if (frame_number < 0)
708
        return -1;
709
    ast->new_frame_offset = frame_number;
710

    
711
    /* find the position */
712
    pos = ast->index_entries[frame_number].pos;
713

    
714
#ifdef DEBUG_SEEK
715
    printf("key_frame_number=%d pos=0x%llx\n", 
716
           frame_number, pos);
717
#endif
718
    
719
    /* update the frame counters for all the other stream by looking
720
       at the positions just after the one found */
721
    for(i = 0; i < s->nb_streams; i++) {
722
        int j;
723
        if (i != stream_index) {
724
            st = s->streams[i];
725
            ast = st->priv_data;
726
            if (ast->nb_index_entries <= 0)
727
                return -1;
728
            j = locate_frame_in_index(ast->index_entries,
729
                                      ast->nb_index_entries,
730
                                      pos);
731
            /* get next frame */
732
            if ((j  + 1) < ast->nb_index_entries)
733
                j++;
734
            /* extract the current frame number */
735
            if (ast->sample_size==0)
736
                ast->new_frame_offset = j;
737
            else
738
                ast->new_frame_offset = ast->index_entries[j].cum_len;
739
        }
740
    }
741
    
742
    /* everything is OK now. We can update the frame offsets */
743
    for(i = 0; i < s->nb_streams; i++) {
744
        st = s->streams[i];
745
        ast = st->priv_data;
746
        ast->frame_offset = ast->new_frame_offset;
747
#ifdef DEBUG_SEEK
748
        printf("%d: frame_offset=%d\n", i, 
749
               ast->frame_offset);
750
#endif
751
    }
752
    if (avi->dv_demux)
753
        dv_flush_audio_packets(avi->dv_demux);
754
    /* do the seek */
755
    pos += avi->movi_list;
756
    url_fseek(&s->pb, pos, SEEK_SET);
757
    return 0;
758
}
759

    
760
static int avi_read_close(AVFormatContext *s)
761
{
762
    int i;
763
    AVIContext *avi = s->priv_data;
764

    
765
    for(i=0;i<s->nb_streams;i++) {
766
        AVStream *st = s->streams[i];
767
        AVIStream *ast = st->priv_data;
768
        if(ast){
769
            av_free(ast->index_entries);
770
            av_free(ast);
771
        }
772
        av_free(st->codec.extradata);
773
        av_free(st->codec.palctrl);
774
    }
775

    
776
    if (avi->dv_demux)
777
        av_free(avi->dv_demux);
778

    
779
    return 0;
780
}
781

    
782
static int avi_probe(AVProbeData *p)
783
{
784
    /* check file header */
785
    if (p->buf_size <= 32)
786
        return 0;
787
    if (p->buf[0] == 'R' && p->buf[1] == 'I' &&
788
        p->buf[2] == 'F' && p->buf[3] == 'F' &&
789
        p->buf[8] == 'A' && p->buf[9] == 'V' &&
790
        p->buf[10] == 'I' && p->buf[11] == ' ')
791
        return AVPROBE_SCORE_MAX;
792
    else
793
        return 0;
794
}
795

    
796
static AVInputFormat avi_iformat = {
797
    "avi",
798
    "avi format",
799
    sizeof(AVIContext),
800
    avi_probe,
801
    avi_read_header,
802
    avi_read_packet,
803
    avi_read_close,
804
    avi_read_seek,
805
};
806

    
807
int avidec_init(void)
808
{
809
    av_register_input_format(&avi_iformat);
810
    return 0;
811
}