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ffmpeg / libavformat / flvdec.c @ 9dd94f83

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1
/*
2
 * FLV demuxer
3
 * Copyright (c) 2003 The Libav Project
4
 *
5
 * This demuxer will generate a 1 byte extradata for VP6F content.
6
 * It is composed of:
7
 *  - upper 4bits: difference between encoded width and visible width
8
 *  - lower 4bits: difference between encoded height and visible height
9
 *
10
 * This file is part of Libav.
11
 *
12
 * Libav is free software; you can redistribute it and/or
13
 * modify it under the terms of the GNU Lesser General Public
14
 * License as published by the Free Software Foundation; either
15
 * version 2.1 of the License, or (at your option) any later version.
16
 *
17
 * Libav is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
20
 * Lesser General Public License for more details.
21
 *
22
 * You should have received a copy of the GNU Lesser General Public
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 * License along with Libav; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
25
 */
26

    
27
#include "libavutil/avstring.h"
28
#include "libavcodec/bytestream.h"
29
#include "libavcodec/mpeg4audio.h"
30
#include "avformat.h"
31
#include "avio_internal.h"
32
#include "flv.h"
33

    
34
typedef struct {
35
    int wrong_dts; ///< wrong dts due to negative cts
36
} FLVContext;
37

    
38
static int flv_probe(AVProbeData *p)
39
{
40
    const uint8_t *d;
41

    
42
    d = p->buf;
43
    if (d[0] == 'F' && d[1] == 'L' && d[2] == 'V' && d[3] < 5 && d[5]==0 && AV_RB32(d+5)>8) {
44
        return AVPROBE_SCORE_MAX;
45
    }
46
    return 0;
47
}
48

    
49
static void flv_set_audio_codec(AVFormatContext *s, AVStream *astream, int flv_codecid) {
50
    AVCodecContext *acodec = astream->codec;
51
    switch(flv_codecid) {
52
        //no distinction between S16 and S8 PCM codec flags
53
        case FLV_CODECID_PCM:
54
            acodec->codec_id = acodec->bits_per_coded_sample == 8 ? CODEC_ID_PCM_U8 :
55
#if HAVE_BIGENDIAN
56
                                CODEC_ID_PCM_S16BE;
57
#else
58
                                CODEC_ID_PCM_S16LE;
59
#endif
60
            break;
61
        case FLV_CODECID_PCM_LE:
62
            acodec->codec_id = acodec->bits_per_coded_sample == 8 ? CODEC_ID_PCM_U8 : CODEC_ID_PCM_S16LE; break;
63
        case FLV_CODECID_AAC  : acodec->codec_id = CODEC_ID_AAC;                                    break;
64
        case FLV_CODECID_ADPCM: acodec->codec_id = CODEC_ID_ADPCM_SWF;                              break;
65
        case FLV_CODECID_SPEEX:
66
            acodec->codec_id = CODEC_ID_SPEEX;
67
            acodec->sample_rate = 16000;
68
            break;
69
        case FLV_CODECID_MP3  : acodec->codec_id = CODEC_ID_MP3      ; astream->need_parsing = AVSTREAM_PARSE_FULL; break;
70
        case FLV_CODECID_NELLYMOSER_8KHZ_MONO:
71
            acodec->sample_rate = 8000; //in case metadata does not otherwise declare samplerate
72
            acodec->codec_id = CODEC_ID_NELLYMOSER;
73
            break;
74
        case FLV_CODECID_NELLYMOSER_16KHZ_MONO:
75
            acodec->sample_rate = 16000;
76
            acodec->codec_id = CODEC_ID_NELLYMOSER;
77
            break;
78
        case FLV_CODECID_NELLYMOSER:
79
            acodec->codec_id = CODEC_ID_NELLYMOSER;
80
            break;
81
        default:
82
            av_log(s, AV_LOG_INFO, "Unsupported audio codec (%x)\n", flv_codecid >> FLV_AUDIO_CODECID_OFFSET);
83
            acodec->codec_tag = flv_codecid >> FLV_AUDIO_CODECID_OFFSET;
84
    }
85
}
86

    
87
static int flv_set_video_codec(AVFormatContext *s, AVStream *vstream, int flv_codecid) {
88
    AVCodecContext *vcodec = vstream->codec;
89
    switch(flv_codecid) {
90
        case FLV_CODECID_H263  : vcodec->codec_id = CODEC_ID_FLV1   ; break;
91
        case FLV_CODECID_SCREEN: vcodec->codec_id = CODEC_ID_FLASHSV; break;
92
        case FLV_CODECID_SCREEN2: vcodec->codec_id = CODEC_ID_FLASHSV2; break;
93
        case FLV_CODECID_VP6   : vcodec->codec_id = CODEC_ID_VP6F   ;
94
        case FLV_CODECID_VP6A  :
95
            if(flv_codecid == FLV_CODECID_VP6A)
96
                vcodec->codec_id = CODEC_ID_VP6A;
97
            if(vcodec->extradata_size != 1) {
98
                vcodec->extradata_size = 1;
99
                vcodec->extradata = av_malloc(1);
100
            }
101
            vcodec->extradata[0] = avio_r8(s->pb);
102
            return 1; // 1 byte body size adjustment for flv_read_packet()
103
        case FLV_CODECID_H264:
104
            vcodec->codec_id = CODEC_ID_H264;
105
            return 3; // not 4, reading packet type will consume one byte
106
        default:
107
            av_log(s, AV_LOG_INFO, "Unsupported video codec (%x)\n", flv_codecid);
108
            vcodec->codec_tag = flv_codecid;
109
    }
110

    
111
    return 0;
112
}
113

    
114
static int amf_get_string(AVIOContext *ioc, char *buffer, int buffsize) {
115
    int length = avio_rb16(ioc);
116
    if(length >= buffsize) {
117
        avio_skip(ioc, length);
118
        return -1;
119
    }
120

    
121
    avio_read(ioc, buffer, length);
122

    
123
    buffer[length] = '\0';
124

    
125
    return length;
126
}
127

    
128
static int amf_parse_object(AVFormatContext *s, AVStream *astream, AVStream *vstream, const char *key, int64_t max_pos, int depth) {
129
    AVCodecContext *acodec, *vcodec;
130
    AVIOContext *ioc;
131
    AMFDataType amf_type;
132
    char str_val[256];
133
    double num_val;
134

    
135
    num_val = 0;
136
    ioc = s->pb;
137

    
138
    amf_type = avio_r8(ioc);
139

    
140
    switch(amf_type) {
141
        case AMF_DATA_TYPE_NUMBER:
142
            num_val = av_int2dbl(avio_rb64(ioc)); break;
143
        case AMF_DATA_TYPE_BOOL:
144
            num_val = avio_r8(ioc); break;
145
        case AMF_DATA_TYPE_STRING:
146
            if(amf_get_string(ioc, str_val, sizeof(str_val)) < 0)
147
                return -1;
148
            break;
149
        case AMF_DATA_TYPE_OBJECT: {
150
            unsigned int keylen;
151

    
152
            while(avio_tell(ioc) < max_pos - 2 && (keylen = avio_rb16(ioc))) {
153
                avio_skip(ioc, keylen); //skip key string
154
                if(amf_parse_object(s, NULL, NULL, NULL, max_pos, depth + 1) < 0)
155
                    return -1; //if we couldn't skip, bomb out.
156
            }
157
            if(avio_r8(ioc) != AMF_END_OF_OBJECT)
158
                return -1;
159
        }
160
            break;
161
        case AMF_DATA_TYPE_NULL:
162
        case AMF_DATA_TYPE_UNDEFINED:
163
        case AMF_DATA_TYPE_UNSUPPORTED:
164
            break; //these take up no additional space
165
        case AMF_DATA_TYPE_MIXEDARRAY:
166
            avio_skip(ioc, 4); //skip 32-bit max array index
167
            while(avio_tell(ioc) < max_pos - 2 && amf_get_string(ioc, str_val, sizeof(str_val)) > 0) {
168
                //this is the only case in which we would want a nested parse to not skip over the object
169
                if(amf_parse_object(s, astream, vstream, str_val, max_pos, depth + 1) < 0)
170
                    return -1;
171
            }
172
            if(avio_r8(ioc) != AMF_END_OF_OBJECT)
173
                return -1;
174
            break;
175
        case AMF_DATA_TYPE_ARRAY: {
176
            unsigned int arraylen, i;
177

    
178
            arraylen = avio_rb32(ioc);
179
            for(i = 0; i < arraylen && avio_tell(ioc) < max_pos - 1; i++) {
180
                if(amf_parse_object(s, NULL, NULL, NULL, max_pos, depth + 1) < 0)
181
                    return -1; //if we couldn't skip, bomb out.
182
            }
183
        }
184
            break;
185
        case AMF_DATA_TYPE_DATE:
186
            avio_skip(ioc, 8 + 2); //timestamp (double) and UTC offset (int16)
187
            break;
188
        default: //unsupported type, we couldn't skip
189
            return -1;
190
    }
191

    
192
    if(depth == 1 && key) { //only look for metadata values when we are not nested and key != NULL
193
        acodec = astream ? astream->codec : NULL;
194
        vcodec = vstream ? vstream->codec : NULL;
195

    
196
        if(amf_type == AMF_DATA_TYPE_BOOL) {
197
            av_strlcpy(str_val, num_val > 0 ? "true" : "false", sizeof(str_val));
198
            av_metadata_set2(&s->metadata, key, str_val, 0);
199
        } else if(amf_type == AMF_DATA_TYPE_NUMBER) {
200
            snprintf(str_val, sizeof(str_val), "%.f", num_val);
201
            av_metadata_set2(&s->metadata, key, str_val, 0);
202
            if(!strcmp(key, "duration")) s->duration = num_val * AV_TIME_BASE;
203
            else if(!strcmp(key, "videodatarate") && vcodec && 0 <= (int)(num_val * 1024.0))
204
                vcodec->bit_rate = num_val * 1024.0;
205
            else if(!strcmp(key, "audiodatarate") && acodec && 0 <= (int)(num_val * 1024.0))
206
                acodec->bit_rate = num_val * 1024.0;
207
        } else if (amf_type == AMF_DATA_TYPE_STRING)
208
            av_metadata_set2(&s->metadata, key, str_val, 0);
209
    }
210

    
211
    return 0;
212
}
213

    
214
static int flv_read_metabody(AVFormatContext *s, int64_t next_pos) {
215
    AMFDataType type;
216
    AVStream *stream, *astream, *vstream;
217
    AVIOContext *ioc;
218
    int i;
219
    char buffer[11]; //only needs to hold the string "onMetaData". Anything longer is something we don't want.
220

    
221
    astream = NULL;
222
    vstream = NULL;
223
    ioc = s->pb;
224

    
225
    //first object needs to be "onMetaData" string
226
    type = avio_r8(ioc);
227
    if(type != AMF_DATA_TYPE_STRING || amf_get_string(ioc, buffer, sizeof(buffer)) < 0 || strcmp(buffer, "onMetaData"))
228
        return -1;
229

    
230
    //find the streams now so that amf_parse_object doesn't need to do the lookup every time it is called.
231
    for(i = 0; i < s->nb_streams; i++) {
232
        stream = s->streams[i];
233
        if     (stream->codec->codec_type == AVMEDIA_TYPE_AUDIO) astream = stream;
234
        else if(stream->codec->codec_type == AVMEDIA_TYPE_VIDEO) vstream = stream;
235
    }
236

    
237
    //parse the second object (we want a mixed array)
238
    if(amf_parse_object(s, astream, vstream, buffer, next_pos, 0) < 0)
239
        return -1;
240

    
241
    return 0;
242
}
243

    
244
static AVStream *create_stream(AVFormatContext *s, int is_audio){
245
    AVStream *st = av_new_stream(s, is_audio);
246
    if (!st)
247
        return NULL;
248
    st->codec->codec_type = is_audio ? AVMEDIA_TYPE_AUDIO : AVMEDIA_TYPE_VIDEO;
249
    av_set_pts_info(st, 32, 1, 1000); /* 32 bit pts in ms */
250
    return st;
251
}
252

    
253
static int flv_read_header(AVFormatContext *s,
254
                           AVFormatParameters *ap)
255
{
256
    int offset, flags;
257

    
258
    avio_skip(s->pb, 4);
259
    flags = avio_r8(s->pb);
260
    /* old flvtool cleared this field */
261
    /* FIXME: better fix needed */
262
    if (!flags) {
263
        flags = FLV_HEADER_FLAG_HASVIDEO | FLV_HEADER_FLAG_HASAUDIO;
264
        av_log(s, AV_LOG_WARNING, "Broken FLV file, which says no streams present, this might fail\n");
265
    }
266

    
267
    if((flags & (FLV_HEADER_FLAG_HASVIDEO|FLV_HEADER_FLAG_HASAUDIO))
268
             != (FLV_HEADER_FLAG_HASVIDEO|FLV_HEADER_FLAG_HASAUDIO))
269
        s->ctx_flags |= AVFMTCTX_NOHEADER;
270

    
271
    if(flags & FLV_HEADER_FLAG_HASVIDEO){
272
        if(!create_stream(s, 0))
273
            return AVERROR(ENOMEM);
274
    }
275
    if(flags & FLV_HEADER_FLAG_HASAUDIO){
276
        if(!create_stream(s, 1))
277
            return AVERROR(ENOMEM);
278
    }
279

    
280
    offset = avio_rb32(s->pb);
281
    avio_seek(s->pb, offset, SEEK_SET);
282
    avio_skip(s->pb, 4);
283

    
284
    s->start_time = 0;
285

    
286
    return 0;
287
}
288

    
289
static int flv_get_extradata(AVFormatContext *s, AVStream *st, int size)
290
{
291
    av_free(st->codec->extradata);
292
    st->codec->extradata = av_mallocz(size + FF_INPUT_BUFFER_PADDING_SIZE);
293
    if (!st->codec->extradata)
294
        return AVERROR(ENOMEM);
295
    st->codec->extradata_size = size;
296
    avio_read(s->pb, st->codec->extradata, st->codec->extradata_size);
297
    return 0;
298
}
299

    
300
static int flv_read_packet(AVFormatContext *s, AVPacket *pkt)
301
{
302
    FLVContext *flv = s->priv_data;
303
    int ret, i, type, size, flags, is_audio;
304
    int64_t next, pos;
305
    int64_t dts, pts = AV_NOPTS_VALUE;
306
    AVStream *st = NULL;
307

    
308
 for(;;avio_skip(s->pb, 4)){ /* pkt size is repeated at end. skip it */
309
    pos = avio_tell(s->pb);
310
    type = avio_r8(s->pb);
311
    size = avio_rb24(s->pb);
312
    dts = avio_rb24(s->pb);
313
    dts |= avio_r8(s->pb) << 24;
314
//    av_log(s, AV_LOG_DEBUG, "type:%d, size:%d, dts:%d\n", type, size, dts);
315
    if (s->pb->eof_reached)
316
        return AVERROR_EOF;
317
    avio_skip(s->pb, 3); /* stream id, always 0 */
318
    flags = 0;
319

    
320
    if(size == 0)
321
        continue;
322

    
323
    next= size + avio_tell(s->pb);
324

    
325
    if (type == FLV_TAG_TYPE_AUDIO) {
326
        is_audio=1;
327
        flags = avio_r8(s->pb);
328
        size--;
329
    } else if (type == FLV_TAG_TYPE_VIDEO) {
330
        is_audio=0;
331
        flags = avio_r8(s->pb);
332
        size--;
333
        if ((flags & 0xf0) == 0x50) /* video info / command frame */
334
            goto skip;
335
    } else {
336
        if (type == FLV_TAG_TYPE_META && size > 13+1+4)
337
            flv_read_metabody(s, next);
338
        else /* skip packet */
339
            av_log(s, AV_LOG_DEBUG, "skipping flv packet: type %d, size %d, flags %d\n", type, size, flags);
340
    skip:
341
        avio_seek(s->pb, next, SEEK_SET);
342
        continue;
343
    }
344

    
345
    /* skip empty data packets */
346
    if (!size)
347
        continue;
348

    
349
    /* now find stream */
350
    for(i=0;i<s->nb_streams;i++) {
351
        st = s->streams[i];
352
        if (st->id == is_audio)
353
            break;
354
    }
355
    if(i == s->nb_streams){
356
        av_log(s, AV_LOG_ERROR, "invalid stream\n");
357
        st= create_stream(s, is_audio);
358
        s->ctx_flags &= ~AVFMTCTX_NOHEADER;
359
    }
360
//    av_log(s, AV_LOG_DEBUG, "%d %X %d \n", is_audio, flags, st->discard);
361
    if(  (st->discard >= AVDISCARD_NONKEY && !((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY ||         is_audio))
362
       ||(st->discard >= AVDISCARD_BIDIR  &&  ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_DISP_INTER && !is_audio))
363
       || st->discard >= AVDISCARD_ALL
364
       ){
365
        avio_seek(s->pb, next, SEEK_SET);
366
        continue;
367
    }
368
    if ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY)
369
        av_add_index_entry(st, pos, dts, size, 0, AVINDEX_KEYFRAME);
370
    break;
371
 }
372

    
373
    // if not streamed and no duration from metadata then seek to end to find the duration from the timestamps
374
    if(!url_is_streamed(s->pb) && (!s->duration || s->duration==AV_NOPTS_VALUE)){
375
        int size;
376
        const int64_t pos= avio_tell(s->pb);
377
        const int64_t fsize= avio_size(s->pb);
378
        avio_seek(s->pb, fsize-4, SEEK_SET);
379
        size= avio_rb32(s->pb);
380
        avio_seek(s->pb, fsize-3-size, SEEK_SET);
381
        if(size == avio_rb24(s->pb) + 11){
382
            uint32_t ts = avio_rb24(s->pb);
383
            ts |= avio_r8(s->pb) << 24;
384
            s->duration = ts * (int64_t)AV_TIME_BASE / 1000;
385
        }
386
        avio_seek(s->pb, pos, SEEK_SET);
387
    }
388

    
389
    if(is_audio){
390
        if(!st->codec->channels || !st->codec->sample_rate || !st->codec->bits_per_coded_sample) {
391
            st->codec->channels = (flags & FLV_AUDIO_CHANNEL_MASK) == FLV_STEREO ? 2 : 1;
392
            st->codec->sample_rate = (44100 << ((flags & FLV_AUDIO_SAMPLERATE_MASK) >> FLV_AUDIO_SAMPLERATE_OFFSET) >> 3);
393
            st->codec->bits_per_coded_sample = (flags & FLV_AUDIO_SAMPLESIZE_MASK) ? 16 : 8;
394
        }
395
        if(!st->codec->codec_id){
396
            flv_set_audio_codec(s, st, flags & FLV_AUDIO_CODECID_MASK);
397
        }
398
    }else{
399
        size -= flv_set_video_codec(s, st, flags & FLV_VIDEO_CODECID_MASK);
400
    }
401

    
402
    if (st->codec->codec_id == CODEC_ID_AAC ||
403
        st->codec->codec_id == CODEC_ID_H264) {
404
        int type = avio_r8(s->pb);
405
        size--;
406
        if (st->codec->codec_id == CODEC_ID_H264) {
407
            int32_t cts = (avio_rb24(s->pb)+0xff800000)^0xff800000; // sign extension
408
            pts = dts + cts;
409
            if (cts < 0) { // dts are wrong
410
                flv->wrong_dts = 1;
411
                av_log(s, AV_LOG_WARNING, "negative cts, previous timestamps might be wrong\n");
412
            }
413
            if (flv->wrong_dts)
414
                dts = AV_NOPTS_VALUE;
415
        }
416
        if (type == 0) {
417
            if ((ret = flv_get_extradata(s, st, size)) < 0)
418
                return ret;
419
            if (st->codec->codec_id == CODEC_ID_AAC) {
420
                MPEG4AudioConfig cfg;
421
                ff_mpeg4audio_get_config(&cfg, st->codec->extradata,
422
                                         st->codec->extradata_size);
423
                st->codec->channels = cfg.channels;
424
                if (cfg.ext_sample_rate)
425
                    st->codec->sample_rate = cfg.ext_sample_rate;
426
                else
427
                    st->codec->sample_rate = cfg.sample_rate;
428
                av_dlog(s, "mp4a config channels %d sample rate %d\n",
429
                        st->codec->channels, st->codec->sample_rate);
430
            }
431

    
432
            ret = AVERROR(EAGAIN);
433
            goto leave;
434
        }
435
    }
436

    
437
    /* skip empty data packets */
438
    if (!size) {
439
        ret = AVERROR(EAGAIN);
440
        goto leave;
441
    }
442

    
443
    ret= av_get_packet(s->pb, pkt, size);
444
    if (ret < 0) {
445
        return AVERROR(EIO);
446
    }
447
    /* note: we need to modify the packet size here to handle the last
448
       packet */
449
    pkt->size = ret;
450
    pkt->dts = dts;
451
    pkt->pts = pts == AV_NOPTS_VALUE ? dts : pts;
452
    pkt->stream_index = st->index;
453

    
454
    if (is_audio || ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY))
455
        pkt->flags |= AV_PKT_FLAG_KEY;
456

    
457
leave:
458
    avio_skip(s->pb, 4);
459
    return ret;
460
}
461

    
462
static int flv_read_seek(AVFormatContext *s, int stream_index,
463
    int64_t ts, int flags)
464
{
465
    return ffio_read_seek(s->pb, stream_index, ts, flags);
466
}
467

    
468
#if 0 /* don't know enough to implement this */
469
static int flv_read_seek2(AVFormatContext *s, int stream_index,
470
    int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
471
{
472
    int ret = AVERROR(ENOSYS);
473

474
    if (ts - min_ts > (uint64_t)(max_ts - ts)) flags |= AVSEEK_FLAG_BACKWARD;
475

476
    if (url_is_streamed(s->pb)) {
477
        if (stream_index < 0) {
478
            stream_index = av_find_default_stream_index(s);
479
            if (stream_index < 0)
480
                return -1;
481

482
            /* timestamp for default must be expressed in AV_TIME_BASE units */
483
            ts = av_rescale_rnd(ts, 1000, AV_TIME_BASE,
484
                flags & AVSEEK_FLAG_BACKWARD ? AV_ROUND_DOWN : AV_ROUND_UP);
485
        }
486
        ret = ffio_read_seek(s->pb, stream_index, ts, flags);
487
    }
488

489
    if (ret == AVERROR(ENOSYS))
490
        ret = av_seek_frame(s, stream_index, ts, flags);
491
    return ret;
492
}
493
#endif
494

    
495
AVInputFormat ff_flv_demuxer = {
496
    "flv",
497
    NULL_IF_CONFIG_SMALL("FLV format"),
498
    sizeof(FLVContext),
499
    flv_probe,
500
    flv_read_header,
501
    flv_read_packet,
502
    .read_seek = flv_read_seek,
503
#if 0
504
    .read_seek2 = flv_read_seek2,
505
#endif
506
    .extensions = "flv",
507
    .value = CODEC_ID_FLV1,
508
};