Statistics
| Branch: | Revision:

ffmpeg / libav / ffm.c @ 16300e23

History | View | Annotate | Download (17.9 KB)

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 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 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 pts;
50
    UINT8 *packet_ptr, *packet_end;
51
    UINT8 packet[FFM_PACKET_SIZE];
52
} FFMContext;
53

    
54
/* disable pts hack for testing */
55
int ffm_nopts = 0;
56

    
57
static void flush_packet(AVFormatContext *s)
58
{
59
    FFMContext *ffm = s->priv_data;
60
    int fill_size, h;
61
    ByteIOContext *pb = &s->pb;
62

    
63
    fill_size = ffm->packet_end - ffm->packet_ptr;
64
    memset(ffm->packet_ptr, 0, fill_size);
65

    
66
    /* put header */
67
    put_be16(pb, PACKET_ID);
68
    put_be16(pb, fill_size);
69
    put_be64(pb, ffm->pts);
70
    h = ffm->frame_offset;
71
    if (ffm->first_packet)
72
        h |= 0x8000;
73
    put_be16(pb, h);
74
    put_buffer(pb, ffm->packet, ffm->packet_end - ffm->packet);
75

    
76
    /* prepare next packet */
77
    ffm->frame_offset = 0; /* no key frame */
78
    ffm->pts = 0; /* no pts */
79
    ffm->packet_ptr = ffm->packet;
80
    ffm->first_packet = 0;
81
}
82

    
83
/* 'first' is true if first data of a frame */
84
static void ffm_write_data(AVFormatContext *s,
85
                           UINT8 *buf, int size,
86
                           INT64 pts, int first)
87
{
88
    FFMContext *ffm = s->priv_data;
89
    int len;
90

    
91
    if (first && ffm->frame_offset == 0)
92
        ffm->frame_offset = ffm->packet_ptr - ffm->packet + FFM_HEADER_SIZE;
93
    if (first && ffm->pts == 0)
94
        ffm->pts = pts;
95

    
96
    /* write as many packets as needed */
97
    while (size > 0) {
98
        len = ffm->packet_end - ffm->packet_ptr;
99
        if (len > size)
100
            len = size;
101
        memcpy(ffm->packet_ptr, buf, len);
102

    
103
        ffm->packet_ptr += len;
104
        buf += len;
105
        size -= len;
106
        if (ffm->packet_ptr >= ffm->packet_end) {
107
            /* special case : no pts in packet : we leave the current one */
108
            if (ffm->pts == 0)
109
                ffm->pts = pts;
110

    
111
            flush_packet(s);
112
        }
113
    }
114
}
115

    
116
static int ffm_write_header(AVFormatContext *s)
117
{
118
    FFMContext *ffm = s->priv_data;
119
    AVStream *st;
120
    FFMStream *fst;
121
    ByteIOContext *pb = &s->pb;
122
    AVCodecContext *codec;
123
    int bit_rate, i;
124

    
125
    ffm->packet_size = FFM_PACKET_SIZE;
126

    
127
    /* header */
128
    put_tag(pb, "FFM1");
129
    put_be32(pb, ffm->packet_size);
130
    /* XXX: store write position in other file ? */
131
    put_be64(pb, ffm->packet_size); /* current write position */
132

    
133
    put_be32(pb, s->nb_streams);
134
    bit_rate = 0;
135
    for(i=0;i<s->nb_streams;i++) {
136
        st = s->streams[i];
137
        bit_rate += st->codec.bit_rate;
138
    }
139
    put_be32(pb, bit_rate);
140

    
141
    /* list of streams */
142
    for(i=0;i<s->nb_streams;i++) {
143
        st = s->streams[i];
144
        fst = av_mallocz(sizeof(FFMStream));
145
        if (!fst)
146
            goto fail;
147
        st->priv_data = fst;
148

    
149
        codec = &st->codec;
150
        /* generic info */
151
        put_be32(pb, codec->codec_id);
152
        put_byte(pb, codec->codec_type);
153
        put_be32(pb, codec->bit_rate);
154
        put_be32(pb, codec->flags);
155
        /* specific info */
156
        switch(codec->codec_type) {
157
        case CODEC_TYPE_VIDEO:
158
            put_be32(pb, (codec->frame_rate * 1000) / FRAME_RATE_BASE);
159
            put_be16(pb, codec->width);
160
            put_be16(pb, codec->height);
161
            put_be16(pb, codec->gop_size);
162
            put_byte(pb, codec->qmin);
163
            put_byte(pb, codec->qmax);
164
            put_byte(pb, codec->max_qdiff);
165
            put_be16(pb, (int) (codec->qcompress * 10000.0));
166
            put_be16(pb, (int) (codec->qblur * 10000.0));
167
            put_be32(pb, codec->bit_rate_tolerance);
168
            break;
169
        case CODEC_TYPE_AUDIO:
170
            put_be32(pb, codec->sample_rate);
171
            put_le16(pb, codec->channels);
172
            put_le16(pb, codec->frame_size);
173
            break;
174
        default:
175
            av_abort();
176
        }
177
        /* hack to have real time */
178
        if (ffm_nopts)
179
            fst->pts = 0;
180
        else
181
            fst->pts = gettime();
182
    }
183

    
184
    /* flush until end of block reached */
185
    while ((url_ftell(pb) % ffm->packet_size) != 0)
186
        put_byte(pb, 0);
187

    
188
    put_flush_packet(pb);
189

    
190
    /* init packet mux */
191
    ffm->packet_ptr = ffm->packet;
192
    ffm->packet_end = ffm->packet + ffm->packet_size - FFM_HEADER_SIZE;
193
    ffm->frame_offset = 0;
194
    ffm->pts = 0;
195
    ffm->first_packet = 1;
196

    
197
    return 0;
198
 fail:
199
    for(i=0;i<s->nb_streams;i++) {
200
        st = s->streams[i];
201
        av_freep(&st->priv_data);
202
    }
203
    return -1;
204
}
205

    
206
static int ffm_write_packet(AVFormatContext *s, int stream_index,
207
                            UINT8 *buf, int size, int force_pts)
208
{
209
    AVStream *st = s->streams[stream_index];
210
    FFMStream *fst = st->priv_data;
211
    INT64 pts;
212
    UINT8 header[FRAME_HEADER_SIZE];
213
    int duration;
214

    
215
    if (st->codec.codec_type == CODEC_TYPE_AUDIO) {
216
        duration = ((float)st->codec.frame_size / st->codec.sample_rate * 1000000.0);
217
    } else {
218
        duration = (1000000.0 * FRAME_RATE_BASE / (float)st->codec.frame_rate);
219
    }
220

    
221
    pts = fst->pts;
222
    /* packet size & key_frame */
223
    header[0] = stream_index;
224
    header[1] = 0;
225
    if (st->codec.key_frame)
226
        header[1] |= FLAG_KEY_FRAME;
227
    header[2] = (size >> 16) & 0xff;
228
    header[3] = (size >> 8) & 0xff;
229
    header[4] = size & 0xff;
230
    header[5] = (duration >> 16) & 0xff;
231
    header[6] = (duration >> 8) & 0xff;
232
    header[7] = duration & 0xff;
233
    ffm_write_data(s, header, FRAME_HEADER_SIZE, pts, 1);
234
    ffm_write_data(s, buf, size, pts, 0);
235

    
236
    fst->pts += duration;
237
    return 0;
238
}
239

    
240
static int ffm_write_trailer(AVFormatContext *s)
241
{
242
    ByteIOContext *pb = &s->pb;
243
    FFMContext *ffm = s->priv_data;
244
    int i;
245

    
246
    /* flush packets */
247
    if (ffm->packet_ptr > ffm->packet)
248
        flush_packet(s);
249

    
250
    put_flush_packet(pb);
251

    
252
    if (!url_is_streamed(pb)) {
253
        INT64 size;
254
        /* update the write offset */
255
        size = url_ftell(pb);
256
        url_fseek(pb, 8, SEEK_SET);
257
        put_be64(pb, size);
258
        put_flush_packet(pb);
259
    }
260

    
261
    for(i=0;i<s->nb_streams;i++)
262
        av_freep(&s->streams[i]->priv_data);
263
    return 0;
264
}
265

    
266
/* ffm demux */
267

    
268
static int ffm_is_avail_data(AVFormatContext *s, int size)
269
{
270
    FFMContext *ffm = s->priv_data;
271
    offset_t pos, avail_size;
272
    int len;
273

    
274
    len = ffm->packet_end - ffm->packet_ptr;
275
    if (!ffm_nopts) {
276
        /* XXX: I don't understand this test, so I disabled it for testing */
277
        if (size <= len)
278
            return 1;
279
    }
280
    pos = url_ftell(&s->pb);
281
    if (pos == ffm->write_index) {
282
        /* exactly at the end of stream */
283
        return 0;
284
    } else if (pos < ffm->write_index) {
285
        avail_size = ffm->write_index - pos;
286
    } else {
287
        avail_size = (ffm->file_size - pos) + (ffm->write_index - FFM_PACKET_SIZE);
288
    }
289
    avail_size = (avail_size / ffm->packet_size) * (ffm->packet_size - FFM_HEADER_SIZE) + len;
290
    if (size <= avail_size)
291
        return 1;
292
    else
293
        return 0;
294
}
295

    
296
/* first is true if we read the frame header */
297
static int ffm_read_data(AVFormatContext *s,
298
                         UINT8 *buf, int size, int first)
299
{
300
    FFMContext *ffm = s->priv_data;
301
    ByteIOContext *pb = &s->pb;
302
    int len, fill_size, size1, frame_offset;
303

    
304
    size1 = size;
305
    while (size > 0) {
306
    redo:
307
        len = ffm->packet_end - ffm->packet_ptr;
308
        if (len > size)
309
            len = size;
310
        if (len == 0) {
311
            if (url_ftell(pb) == ffm->file_size)
312
                url_fseek(pb, ffm->packet_size, SEEK_SET);
313
    retry_read:
314
            get_be16(pb); /* PACKET_ID */
315
            fill_size = get_be16(pb);
316
            ffm->pts = get_be64(pb);
317
            frame_offset = get_be16(pb);
318
            get_buffer(pb, ffm->packet, ffm->packet_size - FFM_HEADER_SIZE);
319
            ffm->packet_end = ffm->packet + (ffm->packet_size - FFM_HEADER_SIZE - fill_size);
320
            /* if first packet or resynchronization packet, we must
321
               handle it specifically */
322
            if (ffm->first_packet || (frame_offset & 0x8000)) {
323
                if (!frame_offset) {
324
                    /* This packet has no frame headers in it */
325
                    if (url_ftell(pb) >= ffm->packet_size * 3) {
326
                        url_fseek(pb, -ffm->packet_size * 2, SEEK_CUR);
327
                        goto retry_read;
328
                    }
329
                    /* This is bad, we cannot find a valid frame header */
330
                    return 0;
331
                }
332
                ffm->first_packet = 0;
333
                if ((frame_offset & 0x7ffff) < FFM_HEADER_SIZE)
334
                    av_abort();
335
                ffm->packet_ptr = ffm->packet + (frame_offset & 0x7fff) - FFM_HEADER_SIZE;
336
                if (!first)
337
                    break;
338
            } else {
339
                ffm->packet_ptr = ffm->packet;
340
            }
341
            goto redo;
342
        }
343
        memcpy(buf, ffm->packet_ptr, len);
344
        buf += len;
345
        ffm->packet_ptr += len;
346
        size -= len;
347
        first = 0;
348
    }
349
    return size1 - size;
350
}
351

    
352

    
353
static int ffm_read_header(AVFormatContext *s, AVFormatParameters *ap)
354
{
355
    FFMContext *ffm = s->priv_data;
356
    AVStream *st;
357
    FFMStream *fst;
358
    ByteIOContext *pb = &s->pb;
359
    AVCodecContext *codec;
360
    int i;
361
    UINT32 tag;
362

    
363
    /* header */
364
    tag = get_le32(pb);
365
    if (tag != MKTAG('F', 'F', 'M', '1'))
366
        goto fail;
367
    ffm->packet_size = get_be32(pb);
368
    if (ffm->packet_size != FFM_PACKET_SIZE)
369
        goto fail;
370
    ffm->write_index = get_be64(pb);
371
    /* get also filesize */
372
    if (!url_is_streamed(pb)) {
373
        ffm->file_size = url_filesize(url_fileno(pb));
374
    } else {
375
        ffm->file_size = (UINT64_C(1) << 63) - 1;
376
    }
377

    
378
    s->nb_streams = get_be32(pb);
379
    get_be32(pb); /* total bitrate */
380
    /* read each stream */
381
    for(i=0;i<s->nb_streams;i++) {
382
        st = av_mallocz(sizeof(AVStream));
383
        if (!st)
384
            goto fail;
385
        s->streams[i] = st;
386
        fst = av_mallocz(sizeof(FFMStream));
387
        if (!fst)
388
            goto fail;
389
        st->priv_data = fst;
390

    
391
        codec = &st->codec;
392
        /* generic info */
393
        st->codec.codec_id = get_be32(pb);
394
        st->codec.codec_type = get_byte(pb); /* codec_type */
395
        codec->bit_rate = get_be32(pb);
396
        codec->flags = get_be32(pb);
397
        /* specific info */
398
        switch(codec->codec_type) {
399
        case CODEC_TYPE_VIDEO:
400
            codec->frame_rate = ((INT64)get_be32(pb) * FRAME_RATE_BASE) / 1000;
401
            codec->width = get_be16(pb);
402
            codec->height = get_be16(pb);
403
            codec->gop_size = get_be16(pb);
404
            codec->qmin = get_byte(pb);
405
            codec->qmax = get_byte(pb);
406
            codec->max_qdiff = get_byte(pb);
407
            codec->qcompress = get_be16(pb) / 10000.0;
408
            codec->qblur = get_be16(pb) / 10000.0;
409
            codec->bit_rate_tolerance = get_be32(pb);
410
            break;
411
        case CODEC_TYPE_AUDIO:
412
            codec->sample_rate = get_be32(pb);
413
            codec->channels = get_le16(pb);
414
            codec->frame_size = get_le16(pb);
415
            break;
416
        default:
417
            av_abort();
418
        }
419

    
420
    }
421

    
422
    /* get until end of block reached */
423
    while ((url_ftell(pb) % ffm->packet_size) != 0)
424
        get_byte(pb);
425

    
426
    /* init packet demux */
427
    ffm->packet_ptr = ffm->packet;
428
    ffm->packet_end = ffm->packet;
429
    ffm->frame_offset = 0;
430
    ffm->pts = 0;
431
    ffm->read_state = READ_HEADER;
432
    ffm->first_packet = 1;
433
    return 0;
434
 fail:
435
    for(i=0;i<s->nb_streams;i++) {
436
        st = s->streams[i];
437
        if (st) {
438
            av_freep(&st->priv_data);
439
            av_free(st);
440
        }
441
    }
442
    return -1;
443
}
444

    
445
/* return < 0 if eof */
446
static int ffm_read_packet(AVFormatContext *s, AVPacket *pkt)
447
{
448
    int size;
449
    FFMContext *ffm = s->priv_data;
450
    int duration;
451

    
452
    switch(ffm->read_state) {
453
    case READ_HEADER:
454
        if (!ffm_is_avail_data(s, FRAME_HEADER_SIZE)) {
455
            return -EAGAIN;
456
        }
457
#if 0
458
        printf("pos=%08Lx spos=%Lx, write_index=%Lx size=%Lx\n",
459
               url_ftell(&s->pb), s->pb.pos, ffm->write_index, ffm->file_size);
460
#endif
461
        if (ffm_read_data(s, ffm->header, FRAME_HEADER_SIZE, 1) != 
462
            FRAME_HEADER_SIZE)
463
            return -EAGAIN;
464
#if 0
465
        {
466
            int i;
467
            for(i=0;i<FRAME_HEADER_SIZE;i++)
468
                printf("%02x ", ffm->header[i]);
469
            printf("\n");
470
        }
471
#endif
472
        ffm->read_state = READ_DATA;
473
        /* fall thru */
474
    case READ_DATA:
475
        size = (ffm->header[2] << 16) | (ffm->header[3] << 8) | ffm->header[4];
476
        if (!ffm_is_avail_data(s, size)) {
477
            return -EAGAIN;
478
        }
479

    
480
        duration = (ffm->header[5] << 16) | (ffm->header[6] << 8) | ffm->header[7];
481

    
482
        av_new_packet(pkt, size);
483
        pkt->stream_index = ffm->header[0];
484
        if (ffm->header[1] & FLAG_KEY_FRAME)
485
            pkt->flags |= PKT_FLAG_KEY;
486

    
487
        ffm->read_state = READ_HEADER;
488
        if (ffm_read_data(s, pkt->data, size, 0) != size) {
489
            /* bad case: desynchronized packet. we cancel all the packet loading */
490
            av_free_packet(pkt);
491
            return -EAGAIN;
492
        }
493
        pkt->pts = ffm->pts;
494
        pkt->duration = duration;
495
        break;
496
    }
497
    return 0;
498
}
499

    
500
//#define DEBUG_SEEK
501

    
502
/* pos is between 0 and file_size - FFM_PACKET_SIZE. It is translated
503
   by the write position inside this function */
504
static void ffm_seek1(AVFormatContext *s, offset_t pos1)
505
{
506
    FFMContext *ffm = s->priv_data;
507
    ByteIOContext *pb = &s->pb;
508
    offset_t pos;
509

    
510
    pos = pos1 + ffm->write_index;
511
    if (pos >= ffm->file_size)
512
        pos -= (ffm->file_size - FFM_PACKET_SIZE);
513
#ifdef DEBUG_SEEK
514
    printf("seek to %Lx -> %Lx\n", pos1, pos);
515
#endif
516
    url_fseek(pb, pos, SEEK_SET);
517
}
518

    
519
static INT64 get_pts(AVFormatContext *s, offset_t pos)
520
{
521
    ByteIOContext *pb = &s->pb;
522
    INT64 pts;
523

    
524
    ffm_seek1(s, pos);
525
    url_fskip(pb, 4);
526
    pts = get_be64(pb);
527
#ifdef DEBUG_SEEK
528
    printf("pts=%0.6f\n", pts / 1000000.0);
529
#endif
530
    return pts;
531
}
532

    
533
/* seek to a given time in the file. The file read pointer is
534
   positionned at or before pts. XXX: the following code is quite
535
   approximative */
536
static int ffm_seek(AVFormatContext *s, INT64 wanted_pts)
537
{
538
    FFMContext *ffm = s->priv_data;
539
    offset_t pos_min, pos_max, pos;
540
    INT64 pts_min, pts_max, pts;
541
    double pos1;
542

    
543
#ifdef DEBUG_SEEK
544
    printf("wanted_pts=%0.6f\n", wanted_pts / 1000000.0);
545
#endif
546
    /* find the position using linear interpolation (better than
547
       dichotomy in typical cases) */
548
    pos_min = 0;
549
    pos_max = ffm->file_size - 2 * FFM_PACKET_SIZE;
550
    while (pos_min <= pos_max) {
551
        pts_min = get_pts(s, pos_min);
552
        pts_max = get_pts(s, pos_max);
553
        /* linear interpolation */
554
        pos1 = (double)(pos_max - pos_min) * (double)(wanted_pts - pts_min) /
555
            (double)(pts_max - pts_min);
556
        pos = (((INT64)pos1) / FFM_PACKET_SIZE) * FFM_PACKET_SIZE;
557
        if (pos <= pos_min)
558
            pos = pos_min;
559
        else if (pos >= pos_max)
560
            pos = pos_max;
561
        pts = get_pts(s, pos);
562
        /* check if we are lucky */
563
        if (pts == wanted_pts) {
564
            goto found;
565
        } else if (pts > wanted_pts) {
566
            pos_max = pos - FFM_PACKET_SIZE;
567
        } else {
568
            pos_min = pos + FFM_PACKET_SIZE;
569
        }
570
    }
571
    pos = pos_min;
572
    if (pos > 0)
573
        pos -= FFM_PACKET_SIZE;
574
 found:
575
    ffm_seek1(s, pos);
576
    return 0;
577
}
578

    
579
offset_t ffm_read_write_index(int fd)
580
{
581
    UINT8 buf[8];
582
    offset_t pos;
583
    int i;
584

    
585
    lseek(fd, 8, SEEK_SET);
586
    read(fd, buf, 8);
587
    pos = 0;
588
    for(i=0;i<8;i++)
589
        pos |= buf[i] << (56 - i * 8);
590
    return pos;
591
}
592

    
593
void ffm_write_write_index(int fd, offset_t pos)
594
{
595
    UINT8 buf[8];
596
    int i;
597

    
598
    for(i=0;i<8;i++)
599
        buf[i] = (pos >> (56 - i * 8)) & 0xff;
600
    lseek(fd, 8, SEEK_SET);
601
    write(fd, buf, 8);
602
}
603

    
604
void ffm_set_write_index(AVFormatContext *s, offset_t pos, offset_t file_size)
605
{
606
    FFMContext *ffm = s->priv_data;
607
    ffm->write_index = pos;
608
    ffm->file_size = file_size;
609
}
610

    
611
static int ffm_read_close(AVFormatContext *s)
612
{
613
    AVStream *st;
614
    int i;
615

    
616
    for(i=0;i<s->nb_streams;i++) {
617
        st = s->streams[i];
618
        av_freep(&st->priv_data);
619
    }
620
    return 0;
621
}
622

    
623
static int ffm_probe(AVProbeData *p)
624
{
625
    if (p->buf_size >= 4 &&
626
        p->buf[0] == 'F' && p->buf[1] == 'F' && p->buf[2] == 'M' && 
627
        p->buf[3] == '1')
628
        return AVPROBE_SCORE_MAX + 1;
629
    return 0;
630
}
631

    
632
AVInputFormat ffm_iformat = {
633
    "ffm",
634
    "ffm format",
635
    sizeof(FFMContext),
636
    ffm_probe,
637
    ffm_read_header,
638
    ffm_read_packet,
639
    ffm_read_close,
640
    ffm_seek,
641
};
642

    
643
AVOutputFormat ffm_oformat = {
644
    "ffm",
645
    "ffm format",
646
    "",
647
    "ffm",
648
    sizeof(FFMContext),
649
    /* not really used */
650
    CODEC_ID_MP2,
651
    CODEC_ID_MPEG1VIDEO,
652
    ffm_write_header,
653
    ffm_write_packet,
654
    ffm_write_trailer,
655
};
656

    
657
int ffm_init(void)
658
{
659
    av_register_input_format(&ffm_iformat);
660
    av_register_output_format(&ffm_oformat);
661
    return 0;
662
}