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ffmpeg / libavformat / ffm.c @ a7eb3c8d

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1
/*
2
 * FFM (ffserver live feed) encoder and 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 <unistd.h>
21

    
22
/* The FFM file is made of blocks of fixed size */
23
#define FFM_HEADER_SIZE 14
24
#define PACKET_ID       0x666d
25

    
26
/* each packet contains frames (which can span several packets */
27
#define FRAME_HEADER_SIZE    8
28
#define FLAG_KEY_FRAME       0x01
29

    
30
typedef struct FFMStream {
31
    int64_t pts;
32
} FFMStream;
33

    
34
enum {
35
    READ_HEADER,
36
    READ_DATA,
37
};
38

    
39
typedef struct FFMContext {
40
    /* only reading mode */
41
    offset_t write_index, file_size;
42
    int read_state;
43
    uint8_t header[FRAME_HEADER_SIZE];
44

    
45
    /* read and write */
46
    int first_packet; /* true if first packet, needed to set the discontinuity tag */
47
    int packet_size;
48
    int frame_offset;
49
    int64_t pts;
50
    uint8_t *packet_ptr, *packet_end;
51
    uint8_t packet[FFM_PACKET_SIZE];
52
} FFMContext;
53

    
54
static int64_t get_pts(AVFormatContext *s, offset_t pos);
55

    
56
/* disable pts hack for testing */
57
int ffm_nopts = 0;
58

    
59
#ifdef CONFIG_ENCODERS
60
static void flush_packet(AVFormatContext *s)
61
{
62
    FFMContext *ffm = s->priv_data;
63
    int fill_size, h;
64
    ByteIOContext *pb = &s->pb;
65

    
66
    fill_size = ffm->packet_end - ffm->packet_ptr;
67
    memset(ffm->packet_ptr, 0, fill_size);
68

    
69
    if (url_ftell(pb) % ffm->packet_size) 
70
        av_abort();
71

    
72
    /* put header */
73
    put_be16(pb, PACKET_ID);
74
    put_be16(pb, fill_size);
75
    put_be64(pb, ffm->pts);
76
    h = ffm->frame_offset;
77
    if (ffm->first_packet)
78
        h |= 0x8000;
79
    put_be16(pb, h);
80
    put_buffer(pb, ffm->packet, ffm->packet_end - ffm->packet);
81

    
82
    /* prepare next packet */
83
    ffm->frame_offset = 0; /* no key frame */
84
    ffm->pts = 0; /* no pts */
85
    ffm->packet_ptr = ffm->packet;
86
    ffm->first_packet = 0;
87
}
88

    
89
/* 'first' is true if first data of a frame */
90
static void ffm_write_data(AVFormatContext *s,
91
                           const uint8_t *buf, int size,
92
                           int64_t pts, int first)
93
{
94
    FFMContext *ffm = s->priv_data;
95
    int len;
96

    
97
    if (first && ffm->frame_offset == 0)
98
        ffm->frame_offset = ffm->packet_ptr - ffm->packet + FFM_HEADER_SIZE;
99
    if (first && ffm->pts == 0)
100
        ffm->pts = pts;
101

    
102
    /* write as many packets as needed */
103
    while (size > 0) {
104
        len = ffm->packet_end - ffm->packet_ptr;
105
        if (len > size)
106
            len = size;
107
        memcpy(ffm->packet_ptr, buf, len);
108

    
109
        ffm->packet_ptr += len;
110
        buf += len;
111
        size -= len;
112
        if (ffm->packet_ptr >= ffm->packet_end) {
113
            /* special case : no pts in packet : we leave the current one */
114
            if (ffm->pts == 0)
115
                ffm->pts = pts;
116

    
117
            flush_packet(s);
118
        }
119
    }
120
}
121

    
122
static int ffm_write_header(AVFormatContext *s)
123
{
124
    FFMContext *ffm = s->priv_data;
125
    AVStream *st;
126
    FFMStream *fst;
127
    ByteIOContext *pb = &s->pb;
128
    AVCodecContext *codec;
129
    int bit_rate, i;
130

    
131
    ffm->packet_size = FFM_PACKET_SIZE;
132

    
133
    /* header */
134
    put_tag(pb, "FFM1");
135
    put_be32(pb, ffm->packet_size);
136
    /* XXX: store write position in other file ? */
137
    put_be64(pb, ffm->packet_size); /* current write position */
138

    
139
    put_be32(pb, s->nb_streams);
140
    bit_rate = 0;
141
    for(i=0;i<s->nb_streams;i++) {
142
        st = s->streams[i];
143
        bit_rate += st->codec.bit_rate;
144
    }
145
    put_be32(pb, bit_rate);
146

    
147
    /* list of streams */
148
    for(i=0;i<s->nb_streams;i++) {
149
        st = s->streams[i];
150
        fst = av_mallocz(sizeof(FFMStream));
151
        if (!fst)
152
            goto fail;
153
        st->priv_data = fst;
154

    
155
        codec = &st->codec;
156
        /* generic info */
157
        put_be32(pb, codec->codec_id);
158
        put_byte(pb, codec->codec_type);
159
        put_be32(pb, codec->bit_rate);
160
        put_be32(pb, st->quality);
161
        put_be32(pb, codec->flags);
162
        /* specific info */
163
        switch(codec->codec_type) {
164
        case CODEC_TYPE_VIDEO:
165
            put_be32(pb, codec->frame_rate_base);
166
            put_be32(pb, codec->frame_rate);
167
            put_be16(pb, codec->width);
168
            put_be16(pb, codec->height);
169
            put_be16(pb, codec->gop_size);
170
            put_byte(pb, codec->qmin);
171
            put_byte(pb, codec->qmax);
172
            put_byte(pb, codec->max_qdiff);
173
            put_be16(pb, (int) (codec->qcompress * 10000.0));
174
            put_be16(pb, (int) (codec->qblur * 10000.0));
175
            put_be32(pb, codec->bit_rate_tolerance);
176
            put_strz(pb, codec->rc_eq);
177
            put_be32(pb, codec->rc_max_rate);
178
            put_be32(pb, codec->rc_min_rate);
179
            put_be32(pb, codec->rc_buffer_size);
180
            put_be64_double(pb, codec->i_quant_factor);
181
            put_be64_double(pb, codec->b_quant_factor);
182
            put_be64_double(pb, codec->i_quant_offset);
183
            put_be64_double(pb, codec->b_quant_offset);
184
            put_be32(pb, codec->dct_algo);
185
            break;
186
        case CODEC_TYPE_AUDIO:
187
            put_be32(pb, codec->sample_rate);
188
            put_le16(pb, codec->channels);
189
            put_le16(pb, codec->frame_size);
190
            break;
191
        default:
192
            av_abort();
193
        }
194
        /* hack to have real time */
195
        if (ffm_nopts)
196
            fst->pts = 0;
197
        else
198
            fst->pts = av_gettime();
199
    }
200

    
201
    /* flush until end of block reached */
202
    while ((url_ftell(pb) % ffm->packet_size) != 0)
203
        put_byte(pb, 0);
204

    
205
    put_flush_packet(pb);
206

    
207
    /* init packet mux */
208
    ffm->packet_ptr = ffm->packet;
209
    ffm->packet_end = ffm->packet + ffm->packet_size - FFM_HEADER_SIZE;
210
    if (ffm->packet_end < ffm->packet)
211
        av_abort();
212
    ffm->frame_offset = 0;
213
    ffm->pts = 0;
214
    ffm->first_packet = 1;
215

    
216
    return 0;
217
 fail:
218
    for(i=0;i<s->nb_streams;i++) {
219
        st = s->streams[i];
220
        av_freep(&st->priv_data);
221
    }
222
    return -1;
223
}
224

    
225
static int ffm_write_packet(AVFormatContext *s, int stream_index,
226
                            const uint8_t *buf, int size, int64_t force_pts)
227
{
228
    AVStream *st = s->streams[stream_index];
229
    FFMStream *fst = st->priv_data;
230
    int64_t pts;
231
    uint8_t header[FRAME_HEADER_SIZE];
232
    int duration;
233

    
234
    if (st->codec.codec_type == CODEC_TYPE_AUDIO) {
235
        duration = ((float)st->codec.frame_size / st->codec.sample_rate * 1000000.0);
236
    } else {
237
        duration = (1000000.0 * st->codec.frame_rate_base / (float)st->codec.frame_rate);
238
    }
239

    
240
    pts = fst->pts;
241
    /* packet size & key_frame */
242
    header[0] = stream_index;
243
    header[1] = 0;
244
    if (st->codec.coded_frame->key_frame) //if st->codec.coded_frame==NULL then there is a bug somewhere else
245
        header[1] |= FLAG_KEY_FRAME;
246
    header[2] = (size >> 16) & 0xff;
247
    header[3] = (size >> 8) & 0xff;
248
    header[4] = size & 0xff;
249
    header[5] = (duration >> 16) & 0xff;
250
    header[6] = (duration >> 8) & 0xff;
251
    header[7] = duration & 0xff;
252
    ffm_write_data(s, header, FRAME_HEADER_SIZE, pts, 1);
253
    ffm_write_data(s, buf, size, pts, 0);
254

    
255
    fst->pts += duration;
256
    return 0;
257
}
258

    
259
static int ffm_write_trailer(AVFormatContext *s)
260
{
261
    ByteIOContext *pb = &s->pb;
262
    FFMContext *ffm = s->priv_data;
263
    int i;
264

    
265
    /* flush packets */
266
    if (ffm->packet_ptr > ffm->packet)
267
        flush_packet(s);
268

    
269
    put_flush_packet(pb);
270

    
271
    if (!url_is_streamed(pb)) {
272
        int64_t size;
273
        /* update the write offset */
274
        size = url_ftell(pb);
275
        url_fseek(pb, 8, SEEK_SET);
276
        put_be64(pb, size);
277
        put_flush_packet(pb);
278
    }
279

    
280
    for(i=0;i<s->nb_streams;i++)
281
        av_freep(&s->streams[i]->priv_data);
282
    return 0;
283
}
284
#endif //CONFIG_ENCODERS
285

    
286
/* ffm demux */
287

    
288
static int ffm_is_avail_data(AVFormatContext *s, int size)
289
{
290
    FFMContext *ffm = s->priv_data;
291
    offset_t pos, avail_size;
292
    int len;
293

    
294
    len = ffm->packet_end - ffm->packet_ptr;
295
    if (!ffm_nopts) {
296
        /* XXX: I don't understand this test, so I disabled it for testing */
297
        if (size <= len)
298
            return 1;
299
    }
300
    pos = url_ftell(&s->pb);
301
    if (pos == ffm->write_index) {
302
        /* exactly at the end of stream */
303
        return 0;
304
    } else if (pos < ffm->write_index) {
305
        avail_size = ffm->write_index - pos;
306
    } else {
307
        avail_size = (ffm->file_size - pos) + (ffm->write_index - FFM_PACKET_SIZE);
308
    }
309
    avail_size = (avail_size / ffm->packet_size) * (ffm->packet_size - FFM_HEADER_SIZE) + len;
310
    if (size <= avail_size)
311
        return 1;
312
    else
313
        return 0;
314
}
315

    
316
/* first is true if we read the frame header */
317
static int ffm_read_data(AVFormatContext *s,
318
                         uint8_t *buf, int size, int first)
319
{
320
    FFMContext *ffm = s->priv_data;
321
    ByteIOContext *pb = &s->pb;
322
    int len, fill_size, size1, frame_offset;
323

    
324
    size1 = size;
325
    while (size > 0) {
326
    redo:
327
        len = ffm->packet_end - ffm->packet_ptr;
328
        if (len > size)
329
            len = size;
330
        if (len == 0) {
331
            if (url_ftell(pb) == ffm->file_size)
332
                url_fseek(pb, ffm->packet_size, SEEK_SET);
333
    retry_read:
334
            get_be16(pb); /* PACKET_ID */
335
            fill_size = get_be16(pb);
336
            ffm->pts = get_be64(pb);
337
            frame_offset = get_be16(pb);
338
            get_buffer(pb, ffm->packet, ffm->packet_size - FFM_HEADER_SIZE);
339
            ffm->packet_end = ffm->packet + (ffm->packet_size - FFM_HEADER_SIZE - fill_size);
340
            if (ffm->packet_end < ffm->packet)
341
                av_abort();
342
            /* if first packet or resynchronization packet, we must
343
               handle it specifically */
344
            if (ffm->first_packet || (frame_offset & 0x8000)) {
345
                if (!frame_offset) {
346
                    /* This packet has no frame headers in it */
347
                    if (url_ftell(pb) >= ffm->packet_size * 3) {
348
                        url_fseek(pb, -ffm->packet_size * 2, SEEK_CUR);
349
                        goto retry_read;
350
                    }
351
                    /* This is bad, we cannot find a valid frame header */
352
                    return 0;
353
                }
354
                ffm->first_packet = 0;
355
                if ((frame_offset & 0x7ffff) < FFM_HEADER_SIZE)
356
                    av_abort();
357
                ffm->packet_ptr = ffm->packet + (frame_offset & 0x7fff) - FFM_HEADER_SIZE;
358
                if (!first)
359
                    break;
360
            } else {
361
                ffm->packet_ptr = ffm->packet;
362
            }
363
            goto redo;
364
        }
365
        memcpy(buf, ffm->packet_ptr, len);
366
        buf += len;
367
        ffm->packet_ptr += len;
368
        size -= len;
369
        first = 0;
370
    }
371
    return size1 - size;
372
}
373

    
374

    
375
static void adjust_write_index(AVFormatContext *s)
376
{
377
    FFMContext *ffm = s->priv_data;
378
    ByteIOContext *pb = &s->pb;
379
    int64_t pts;
380
    //offset_t orig_write_index = ffm->write_index;
381
    offset_t pos_min, pos_max;
382
    int64_t pts_start;
383
    offset_t ptr = url_ftell(pb);
384

    
385

    
386
    pos_min = 0;
387
    pos_max = ffm->file_size - 2 * FFM_PACKET_SIZE;
388

    
389
    pts_start = get_pts(s, pos_min);
390

    
391
    pts = get_pts(s, pos_max);
392

    
393
    if (pts - 100000 > pts_start) 
394
        return;
395

    
396
    ffm->write_index = FFM_PACKET_SIZE;
397

    
398
    pts_start = get_pts(s, pos_min);
399

    
400
    pts = get_pts(s, pos_max);
401

    
402
    if (pts - 100000 <= pts_start) {
403
        while (1) {
404
            offset_t newpos;
405
            int64_t newpts;
406

    
407
            newpos = ((pos_max + pos_min) / (2 * FFM_PACKET_SIZE)) * FFM_PACKET_SIZE;
408

    
409
            if (newpos == pos_min)
410
                break;
411

    
412
            newpts = get_pts(s, newpos);
413

    
414
            if (newpts - 100000 <= pts) {
415
                pos_max = newpos;
416
                pts = newpts;
417
            } else {
418
                pos_min = newpos;
419
            }
420
        }
421
        ffm->write_index += pos_max;
422
    }
423

    
424
    //printf("Adjusted write index from %lld to %lld: pts=%0.6f\n", orig_write_index, ffm->write_index, pts / 1000000.);
425
    //printf("pts range %0.6f - %0.6f\n", get_pts(s, 0) / 1000000. , get_pts(s, ffm->file_size - 2 * FFM_PACKET_SIZE) / 1000000. );
426

    
427
    url_fseek(pb, ptr, SEEK_SET);
428
}
429

    
430

    
431
static int ffm_read_header(AVFormatContext *s, AVFormatParameters *ap)
432
{
433
    FFMContext *ffm = s->priv_data;
434
    AVStream *st;
435
    FFMStream *fst;
436
    ByteIOContext *pb = &s->pb;
437
    AVCodecContext *codec;
438
    int i, nb_streams;
439
    uint32_t tag;
440

    
441
    /* header */
442
    tag = get_le32(pb);
443
    if (tag != MKTAG('F', 'F', 'M', '1'))
444
        goto fail;
445
    ffm->packet_size = get_be32(pb);
446
    if (ffm->packet_size != FFM_PACKET_SIZE)
447
        goto fail;
448
    ffm->write_index = get_be64(pb);
449
    /* get also filesize */
450
    if (!url_is_streamed(pb)) {
451
        ffm->file_size = url_filesize(url_fileno(pb));
452
        adjust_write_index(s);
453
    } else {
454
        ffm->file_size = (uint64_t_C(1) << 63) - 1;
455
    }
456

    
457
    nb_streams = get_be32(pb);
458
    get_be32(pb); /* total bitrate */
459
    /* read each stream */
460
    for(i=0;i<nb_streams;i++) {
461
        char rc_eq_buf[128];
462

    
463
        st = av_new_stream(s, 0);
464
        if (!st)
465
            goto fail;
466
        fst = av_mallocz(sizeof(FFMStream));
467
        if (!fst)
468
            goto fail;
469
        st->priv_data = fst;
470

    
471
        codec = &st->codec;
472
        /* generic info */
473
        st->codec.codec_id = get_be32(pb);
474
        st->codec.codec_type = get_byte(pb); /* codec_type */
475
        codec->bit_rate = get_be32(pb);
476
        st->quality = get_be32(pb);
477
        codec->flags = get_be32(pb);
478
        /* specific info */
479
        switch(codec->codec_type) {
480
        case CODEC_TYPE_VIDEO:
481
            codec->frame_rate_base = get_be32(pb);
482
            codec->frame_rate = get_be32(pb);
483
            codec->width = get_be16(pb);
484
            codec->height = get_be16(pb);
485
            codec->gop_size = get_be16(pb);
486
            codec->qmin = get_byte(pb);
487
            codec->qmax = get_byte(pb);
488
            codec->max_qdiff = get_byte(pb);
489
            codec->qcompress = get_be16(pb) / 10000.0;
490
            codec->qblur = get_be16(pb) / 10000.0;
491
            codec->bit_rate_tolerance = get_be32(pb);
492
            codec->rc_eq = av_strdup(get_strz(pb, rc_eq_buf, sizeof(rc_eq_buf)));
493
            codec->rc_max_rate = get_be32(pb);
494
            codec->rc_min_rate = get_be32(pb);
495
            codec->rc_buffer_size = get_be32(pb);
496
            codec->i_quant_factor = get_be64_double(pb);
497
            codec->b_quant_factor = get_be64_double(pb);
498
            codec->i_quant_offset = get_be64_double(pb);
499
            codec->b_quant_offset = get_be64_double(pb);
500
            codec->dct_algo = get_be32(pb);
501
            break;
502
        case CODEC_TYPE_AUDIO:
503
            codec->sample_rate = get_be32(pb);
504
            codec->channels = get_le16(pb);
505
            codec->frame_size = get_le16(pb);
506
            break;
507
        default:
508
            goto fail;
509
        }
510

    
511
    }
512

    
513
    /* get until end of block reached */
514
    while ((url_ftell(pb) % ffm->packet_size) != 0)
515
        get_byte(pb);
516

    
517
    /* init packet demux */
518
    ffm->packet_ptr = ffm->packet;
519
    ffm->packet_end = ffm->packet;
520
    ffm->frame_offset = 0;
521
    ffm->pts = 0;
522
    ffm->read_state = READ_HEADER;
523
    ffm->first_packet = 1;
524
    return 0;
525
 fail:
526
    for(i=0;i<s->nb_streams;i++) {
527
        st = s->streams[i];
528
        if (st) {
529
            av_freep(&st->priv_data);
530
            av_free(st);
531
        }
532
    }
533
    return -1;
534
}
535

    
536
/* return < 0 if eof */
537
static int ffm_read_packet(AVFormatContext *s, AVPacket *pkt)
538
{
539
    int size;
540
    FFMContext *ffm = s->priv_data;
541
    int duration;
542

    
543
    switch(ffm->read_state) {
544
    case READ_HEADER:
545
        if (!ffm_is_avail_data(s, FRAME_HEADER_SIZE)) {
546
            return -EAGAIN;
547
        }
548
#if 0
549
        printf("pos=%08Lx spos=%Lx, write_index=%Lx size=%Lx\n",
550
               url_ftell(&s->pb), s->pb.pos, ffm->write_index, ffm->file_size);
551
#endif
552
        if (ffm_read_data(s, ffm->header, FRAME_HEADER_SIZE, 1) != 
553
            FRAME_HEADER_SIZE)
554
            return -EAGAIN;
555
#if 0
556
        {
557
            int i;
558
            for(i=0;i<FRAME_HEADER_SIZE;i++)
559
                printf("%02x ", ffm->header[i]);
560
            printf("\n");
561
        }
562
#endif
563
        ffm->read_state = READ_DATA;
564
        /* fall thru */
565
    case READ_DATA:
566
        size = (ffm->header[2] << 16) | (ffm->header[3] << 8) | ffm->header[4];
567
        if (!ffm_is_avail_data(s, size)) {
568
            return -EAGAIN;
569
        }
570

    
571
        duration = (ffm->header[5] << 16) | (ffm->header[6] << 8) | ffm->header[7];
572

    
573
        av_new_packet(pkt, size);
574
        pkt->stream_index = ffm->header[0];
575
        if (ffm->header[1] & FLAG_KEY_FRAME)
576
            pkt->flags |= PKT_FLAG_KEY;
577

    
578
        ffm->read_state = READ_HEADER;
579
        if (ffm_read_data(s, pkt->data, size, 0) != size) {
580
            /* bad case: desynchronized packet. we cancel all the packet loading */
581
            av_free_packet(pkt);
582
            return -EAGAIN;
583
        }
584
        pkt->pts = ffm->pts;
585
        pkt->duration = duration;
586
        break;
587
    }
588
    return 0;
589
}
590

    
591
//#define DEBUG_SEEK
592

    
593
/* pos is between 0 and file_size - FFM_PACKET_SIZE. It is translated
594
   by the write position inside this function */
595
static void ffm_seek1(AVFormatContext *s, offset_t pos1)
596
{
597
    FFMContext *ffm = s->priv_data;
598
    ByteIOContext *pb = &s->pb;
599
    offset_t pos;
600

    
601
    pos = pos1 + ffm->write_index;
602
    if (pos >= ffm->file_size)
603
        pos -= (ffm->file_size - FFM_PACKET_SIZE);
604
#ifdef DEBUG_SEEK
605
    printf("seek to %Lx -> %Lx\n", pos1, pos);
606
#endif
607
    url_fseek(pb, pos, SEEK_SET);
608
}
609

    
610
static int64_t get_pts(AVFormatContext *s, offset_t pos)
611
{
612
    ByteIOContext *pb = &s->pb;
613
    int64_t pts;
614

    
615
    ffm_seek1(s, pos);
616
    url_fskip(pb, 4);
617
    pts = get_be64(pb);
618
#ifdef DEBUG_SEEK
619
    printf("pts=%0.6f\n", pts / 1000000.0);
620
#endif
621
    return pts;
622
}
623

    
624
/* seek to a given time in the file. The file read pointer is
625
   positionned at or before pts. XXX: the following code is quite
626
   approximative */
627
static int ffm_seek(AVFormatContext *s, int64_t wanted_pts)
628
{
629
    FFMContext *ffm = s->priv_data;
630
    offset_t pos_min, pos_max, pos;
631
    int64_t pts_min, pts_max, pts;
632
    double pos1;
633

    
634
#ifdef DEBUG_SEEK
635
    printf("wanted_pts=%0.6f\n", wanted_pts / 1000000.0);
636
#endif
637
    /* find the position using linear interpolation (better than
638
       dichotomy in typical cases) */
639
    pos_min = 0;
640
    pos_max = ffm->file_size - 2 * FFM_PACKET_SIZE;
641
    while (pos_min <= pos_max) {
642
        pts_min = get_pts(s, pos_min);
643
        pts_max = get_pts(s, pos_max);
644
        /* linear interpolation */
645
        pos1 = (double)(pos_max - pos_min) * (double)(wanted_pts - pts_min) /
646
            (double)(pts_max - pts_min);
647
        pos = (((int64_t)pos1) / FFM_PACKET_SIZE) * FFM_PACKET_SIZE;
648
        if (pos <= pos_min)
649
            pos = pos_min;
650
        else if (pos >= pos_max)
651
            pos = pos_max;
652
        pts = get_pts(s, pos);
653
        /* check if we are lucky */
654
        if (pts == wanted_pts) {
655
            goto found;
656
        } else if (pts > wanted_pts) {
657
            pos_max = pos - FFM_PACKET_SIZE;
658
        } else {
659
            pos_min = pos + FFM_PACKET_SIZE;
660
        }
661
    }
662
    pos = pos_min;
663
    if (pos > 0)
664
        pos -= FFM_PACKET_SIZE;
665
 found:
666
    ffm_seek1(s, pos);
667
    return 0;
668
}
669

    
670
offset_t ffm_read_write_index(int fd)
671
{
672
    uint8_t buf[8];
673
    offset_t pos;
674
    int i;
675

    
676
    lseek(fd, 8, SEEK_SET);
677
    read(fd, buf, 8);
678
    pos = 0;
679
    for(i=0;i<8;i++)
680
        pos |= (int64_t)buf[i] << (56 - i * 8);
681
    return pos;
682
}
683

    
684
void ffm_write_write_index(int fd, offset_t pos)
685
{
686
    uint8_t buf[8];
687
    int i;
688

    
689
    for(i=0;i<8;i++)
690
        buf[i] = (pos >> (56 - i * 8)) & 0xff;
691
    lseek(fd, 8, SEEK_SET);
692
    write(fd, buf, 8);
693
}
694

    
695
void ffm_set_write_index(AVFormatContext *s, offset_t pos, offset_t file_size)
696
{
697
    FFMContext *ffm = s->priv_data;
698
    ffm->write_index = pos;
699
    ffm->file_size = file_size;
700
}
701

    
702
static int ffm_read_close(AVFormatContext *s)
703
{
704
    AVStream *st;
705
    int i;
706

    
707
    for(i=0;i<s->nb_streams;i++) {
708
        st = s->streams[i];
709
        av_freep(&st->priv_data);
710
    }
711
    return 0;
712
}
713

    
714
static int ffm_probe(AVProbeData *p)
715
{
716
    if (p->buf_size >= 4 &&
717
        p->buf[0] == 'F' && p->buf[1] == 'F' && p->buf[2] == 'M' && 
718
        p->buf[3] == '1')
719
        return AVPROBE_SCORE_MAX + 1;
720
    return 0;
721
}
722

    
723
static AVInputFormat ffm_iformat = {
724
    "ffm",
725
    "ffm format",
726
    sizeof(FFMContext),
727
    ffm_probe,
728
    ffm_read_header,
729
    ffm_read_packet,
730
    ffm_read_close,
731
    ffm_seek,
732
};
733

    
734
#ifdef CONFIG_ENCODERS
735
static AVOutputFormat ffm_oformat = {
736
    "ffm",
737
    "ffm format",
738
    "",
739
    "ffm",
740
    sizeof(FFMContext),
741
    /* not really used */
742
    CODEC_ID_MP2,
743
    CODEC_ID_MPEG1VIDEO,
744
    ffm_write_header,
745
    ffm_write_packet,
746
    ffm_write_trailer,
747
};
748
#endif //CONFIG_ENCODERS
749

    
750
int ffm_init(void)
751
{
752
    av_register_input_format(&ffm_iformat);
753
#ifdef CONFIG_ENCODERS
754
    av_register_output_format(&ffm_oformat);
755
#endif //CONFIG_ENCODERS
756
    return 0;
757
}