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ffmpeg / libavformat / flvdec.c @ 12ad6671

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

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

    
33
typedef struct {
34
    int wrong_dts; ///< wrong dts due to negative cts
35
} FLVContext;
36

    
37
static int flv_probe(AVProbeData *p)
38
{
39
    const uint8_t *d;
40

    
41
    d = p->buf;
42
    if (d[0] == 'F' && d[1] == 'L' && d[2] == 'V' && d[3] < 5 && d[5]==0 && AV_RB32(d+5)>8) {
43
        return AVPROBE_SCORE_MAX;
44
    }
45
    return 0;
46
}
47

    
48
static void flv_set_audio_codec(AVFormatContext *s, AVStream *astream, int flv_codecid) {
49
    AVCodecContext *acodec = astream->codec;
50
    switch(flv_codecid) {
51
        //no distinction between S16 and S8 PCM codec flags
52
        case FLV_CODECID_PCM:
53
            acodec->codec_id = acodec->bits_per_coded_sample == 8 ? CODEC_ID_PCM_S8 :
54
#if HAVE_BIGENDIAN
55
                                CODEC_ID_PCM_S16BE;
56
#else
57
                                CODEC_ID_PCM_S16LE;
58
#endif
59
            break;
60
        case FLV_CODECID_PCM_LE:
61
            acodec->codec_id = acodec->bits_per_coded_sample == 8 ? CODEC_ID_PCM_S8 : CODEC_ID_PCM_S16LE; break;
62
        case FLV_CODECID_AAC  : acodec->codec_id = CODEC_ID_AAC;                                    break;
63
        case FLV_CODECID_ADPCM: acodec->codec_id = CODEC_ID_ADPCM_SWF;                              break;
64
        case FLV_CODECID_SPEEX:
65
            acodec->codec_id = CODEC_ID_SPEEX;
66
            acodec->sample_rate = 16000;
67
            break;
68
        case FLV_CODECID_MP3  : acodec->codec_id = CODEC_ID_MP3      ; astream->need_parsing = AVSTREAM_PARSE_FULL; break;
69
        case FLV_CODECID_NELLYMOSER_8KHZ_MONO:
70
            acodec->sample_rate = 8000; //in case metadata does not otherwise declare samplerate
71
        case FLV_CODECID_NELLYMOSER:
72
            acodec->codec_id = CODEC_ID_NELLYMOSER;
73
            break;
74
        default:
75
            av_log(s, AV_LOG_INFO, "Unsupported audio codec (%x)\n", flv_codecid >> FLV_AUDIO_CODECID_OFFSET);
76
            acodec->codec_tag = flv_codecid >> FLV_AUDIO_CODECID_OFFSET;
77
    }
78
}
79

    
80
static int flv_set_video_codec(AVFormatContext *s, AVStream *vstream, int flv_codecid) {
81
    AVCodecContext *vcodec = vstream->codec;
82
    switch(flv_codecid) {
83
        case FLV_CODECID_H263  : vcodec->codec_id = CODEC_ID_FLV1   ; break;
84
        case FLV_CODECID_SCREEN: vcodec->codec_id = CODEC_ID_FLASHSV; break;
85
        case FLV_CODECID_SCREEN2: vcodec->codec_id = CODEC_ID_FLASHSV2; break;
86
        case FLV_CODECID_VP6   : vcodec->codec_id = CODEC_ID_VP6F   ;
87
        case FLV_CODECID_VP6A  :
88
            if(flv_codecid == FLV_CODECID_VP6A)
89
                vcodec->codec_id = CODEC_ID_VP6A;
90
            if(vcodec->extradata_size != 1) {
91
                vcodec->extradata_size = 1;
92
                vcodec->extradata = av_malloc(1);
93
            }
94
            vcodec->extradata[0] = get_byte(s->pb);
95
            return 1; // 1 byte body size adjustment for flv_read_packet()
96
        case FLV_CODECID_H264:
97
            vcodec->codec_id = CODEC_ID_H264;
98
            return 3; // not 4, reading packet type will consume one byte
99
        default:
100
            av_log(s, AV_LOG_INFO, "Unsupported video codec (%x)\n", flv_codecid);
101
            vcodec->codec_tag = flv_codecid;
102
    }
103

    
104
    return 0;
105
}
106

    
107
static int amf_get_string(ByteIOContext *ioc, char **buf)
108
{
109
    uint16_t len = get_be16(ioc);
110

    
111
    *buf = av_malloc(len+1);
112
    if (!*buf)
113
        return AVERROR_NOMEM;
114

    
115
    get_buffer(ioc, *buf, len);
116
    (*buf)[len] = '\0';
117

    
118
    return len;
119
}
120

    
121
static int amf_parse_object(AVFormatContext *s, AVStream *astream, AVStream *vstream, const char *key, int64_t max_pos, int depth) {
122
    AVCodecContext *acodec, *vcodec;
123
    ByteIOContext *ioc;
124
    AMFDataType amf_type;
125
    char *str = NULL;
126
    double num_val;
127

    
128
    num_val = 0;
129
    ioc = s->pb;
130

    
131
    amf_type = get_byte(ioc);
132

    
133
    switch(amf_type) {
134
        case AMF_DATA_TYPE_NUMBER:
135
            num_val = av_int2dbl(get_be64(ioc)); break;
136
        case AMF_DATA_TYPE_BOOL:
137
            num_val = get_byte(ioc); break;
138
        case AMF_DATA_TYPE_STRING:
139
            if(amf_get_string(ioc, &str) < 0)
140
                return -1;
141
            break;
142
        case AMF_DATA_TYPE_OBJECT: {
143
            unsigned int keylen;
144

    
145
            while(url_ftell(ioc) < max_pos - 2 && (keylen = get_be16(ioc))) {
146
                url_fskip(ioc, keylen); //skip key string
147
                if(amf_parse_object(s, NULL, NULL, NULL, max_pos, depth + 1) < 0)
148
                    return -1; //if we couldn't skip, bomb out.
149
            }
150
            if(get_byte(ioc) != AMF_END_OF_OBJECT)
151
                return -1;
152
        }
153
            break;
154
        case AMF_DATA_TYPE_NULL:
155
        case AMF_DATA_TYPE_UNDEFINED:
156
        case AMF_DATA_TYPE_UNSUPPORTED:
157
            break; //these take up no additional space
158
        case AMF_DATA_TYPE_MIXEDARRAY:
159
            url_fskip(ioc, 4); //skip 32-bit max array index
160
            while(url_ftell(ioc) < max_pos - 2 && amf_get_string(ioc, &str) > 0) {
161
                //this is the only case in which we would want a nested parse to not skip over the object
162
                if(amf_parse_object(s, astream, vstream, str, max_pos, depth + 1) < 0)
163
                    return -1;
164
                av_freep(&str);
165
            }
166
            if(get_byte(ioc) != AMF_END_OF_OBJECT)
167
                return -1;
168
            break;
169
        case AMF_DATA_TYPE_ARRAY: {
170
            unsigned int arraylen, i;
171

    
172
            arraylen = get_be32(ioc);
173
            for(i = 0; i < arraylen && url_ftell(ioc) < max_pos - 1; i++) {
174
                if(amf_parse_object(s, NULL, NULL, NULL, max_pos, depth + 1) < 0)
175
                    return -1; //if we couldn't skip, bomb out.
176
            }
177
        }
178
            break;
179
        case AMF_DATA_TYPE_DATE:
180
            url_fskip(ioc, 8 + 2); //timestamp (double) and UTC offset (int16)
181
            break;
182
        default: //unsupported type, we couldn't skip
183
            return -1;
184
    }
185

    
186
    if(depth == 1 && key) { //only look for metadata values when we are not nested and key != NULL
187
        acodec = astream ? astream->codec : NULL;
188
        vcodec = vstream ? vstream->codec : NULL;
189

    
190
        if(amf_type == AMF_DATA_TYPE_BOOL) {
191
            av_metadata_set2(&s->metadata, key, av_d2str(num_val), AV_METADATA_DONT_STRDUP_VAL);
192
        } else if(amf_type == AMF_DATA_TYPE_NUMBER) {
193
            av_metadata_set2(&s->metadata, key, av_d2str(num_val), AV_METADATA_DONT_STRDUP_VAL);
194
            if(!strcmp(key, "duration")) s->duration = num_val * AV_TIME_BASE;
195
            else if(!strcmp(key, "videodatarate") && vcodec && 0 <= (int)(num_val * 1024.0))
196
                vcodec->bit_rate = num_val * 1024.0;
197
        } else if (amf_type == AMF_DATA_TYPE_STRING)
198
            av_metadata_set2(&s->metadata, key, str,
199
                                   AV_METADATA_DONT_STRDUP_VAL);
200
    }
201

    
202
    return 0;
203
}
204

    
205
static int flv_read_metabody(AVFormatContext *s, int64_t next_pos) {
206
    AMFDataType type;
207
    AVStream *stream, *astream, *vstream;
208
    ByteIOContext *ioc;
209
    int i;
210
    char *buf = NULL; //only needs to hold the string "onMetaData". Anything longer is something we don't want.
211

    
212
    astream = NULL;
213
    vstream = NULL;
214
    ioc = s->pb;
215

    
216
    //first object needs to be "onMetaData" string
217
    type = get_byte(ioc);
218
    if (type != AMF_DATA_TYPE_STRING ||
219
        amf_get_string(ioc, &buf) < 0 || strcmp(buf, "onMetaData")) {
220
        av_freep(&buf);
221
        return -1;
222
    }
223

    
224
    //find the streams now so that amf_parse_object doesn't need to do the lookup every time it is called.
225
    for(i = 0; i < s->nb_streams; i++) {
226
        stream = s->streams[i];
227
        if     (stream->codec->codec_type == CODEC_TYPE_AUDIO) astream = stream;
228
        else if(stream->codec->codec_type == CODEC_TYPE_VIDEO) vstream = stream;
229
    }
230

    
231
    //parse the second object (we want a mixed array)
232
    if(amf_parse_object(s, astream, vstream, buf, next_pos, 0) < 0)
233
        return -1;
234
    av_freep(&buf);
235

    
236
    return 0;
237
}
238

    
239
static AVStream *create_stream(AVFormatContext *s, int is_audio){
240
    AVStream *st = av_new_stream(s, is_audio);
241
    if (!st)
242
        return NULL;
243
    st->codec->codec_type = is_audio ? CODEC_TYPE_AUDIO : CODEC_TYPE_VIDEO;
244
    av_set_pts_info(st, 32, 1, 1000); /* 32 bit pts in ms */
245
    return st;
246
}
247

    
248
static int flv_read_header(AVFormatContext *s,
249
                           AVFormatParameters *ap)
250
{
251
    int offset, flags;
252

    
253
    url_fskip(s->pb, 4);
254
    flags = get_byte(s->pb);
255
    /* old flvtool cleared this field */
256
    /* FIXME: better fix needed */
257
    if (!flags) {
258
        flags = FLV_HEADER_FLAG_HASVIDEO | FLV_HEADER_FLAG_HASAUDIO;
259
        av_log(s, AV_LOG_WARNING, "Broken FLV file, which says no streams present, this might fail\n");
260
    }
261

    
262
    if((flags & (FLV_HEADER_FLAG_HASVIDEO|FLV_HEADER_FLAG_HASAUDIO))
263
             != (FLV_HEADER_FLAG_HASVIDEO|FLV_HEADER_FLAG_HASAUDIO))
264
        s->ctx_flags |= AVFMTCTX_NOHEADER;
265

    
266
    if(flags & FLV_HEADER_FLAG_HASVIDEO){
267
        if(!create_stream(s, 0))
268
            return AVERROR(ENOMEM);
269
    }
270
    if(flags & FLV_HEADER_FLAG_HASAUDIO){
271
        if(!create_stream(s, 1))
272
            return AVERROR(ENOMEM);
273
    }
274

    
275
    offset = get_be32(s->pb);
276
    url_fseek(s->pb, offset, SEEK_SET);
277

    
278
    s->start_time = 0;
279

    
280
    return 0;
281
}
282

    
283
static int flv_get_extradata(AVFormatContext *s, AVStream *st, int size)
284
{
285
    av_free(st->codec->extradata);
286
    st->codec->extradata = av_mallocz(size + FF_INPUT_BUFFER_PADDING_SIZE);
287
    if (!st->codec->extradata)
288
        return AVERROR(ENOMEM);
289
    st->codec->extradata_size = size;
290
    get_buffer(s->pb, st->codec->extradata, st->codec->extradata_size);
291
    return 0;
292
}
293

    
294
static int flv_read_packet(AVFormatContext *s, AVPacket *pkt)
295
{
296
    FLVContext *flv = s->priv_data;
297
    int ret, i, type, size, flags, is_audio;
298
    int64_t next, pos;
299
    int64_t dts, pts = AV_NOPTS_VALUE;
300
    AVStream *st = NULL;
301

    
302
 for(;;){
303
    pos = url_ftell(s->pb);
304
    url_fskip(s->pb, 4); /* size of previous packet */
305
    type = get_byte(s->pb);
306
    size = get_be24(s->pb);
307
    dts = get_be24(s->pb);
308
    dts |= get_byte(s->pb) << 24;
309
//    av_log(s, AV_LOG_DEBUG, "type:%d, size:%d, dts:%d\n", type, size, dts);
310
    if (url_feof(s->pb))
311
        return AVERROR_EOF;
312
    url_fskip(s->pb, 3); /* stream id, always 0 */
313
    flags = 0;
314

    
315
    if(size == 0)
316
        continue;
317

    
318
    next= size + url_ftell(s->pb);
319

    
320
    if (type == FLV_TAG_TYPE_AUDIO) {
321
        is_audio=1;
322
        flags = get_byte(s->pb);
323
        size--;
324
    } else if (type == FLV_TAG_TYPE_VIDEO) {
325
        is_audio=0;
326
        flags = get_byte(s->pb);
327
        size--;
328
        if ((flags & 0xf0) == 0x50) /* video info / command frame */
329
            goto skip;
330
    } else {
331
        if (type == FLV_TAG_TYPE_META && size > 13+1+4)
332
            flv_read_metabody(s, next);
333
        else /* skip packet */
334
            av_log(s, AV_LOG_DEBUG, "skipping flv packet: type %d, size %d, flags %d\n", type, size, flags);
335
    skip:
336
        url_fseek(s->pb, next, SEEK_SET);
337
        continue;
338
    }
339

    
340
    /* skip empty data packets */
341
    if (!size)
342
        continue;
343

    
344
    /* now find stream */
345
    for(i=0;i<s->nb_streams;i++) {
346
        st = s->streams[i];
347
        if (st->id == is_audio)
348
            break;
349
    }
350
    if(i == s->nb_streams){
351
        av_log(s, AV_LOG_ERROR, "invalid stream\n");
352
        st= create_stream(s, is_audio);
353
        s->ctx_flags &= ~AVFMTCTX_NOHEADER;
354
    }
355
//    av_log(s, AV_LOG_DEBUG, "%d %X %d \n", is_audio, flags, st->discard);
356
    if(  (st->discard >= AVDISCARD_NONKEY && !((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY ||         is_audio))
357
       ||(st->discard >= AVDISCARD_BIDIR  &&  ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_DISP_INTER && !is_audio))
358
       || st->discard >= AVDISCARD_ALL
359
       ){
360
        url_fseek(s->pb, next, SEEK_SET);
361
        continue;
362
    }
363
    if ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY)
364
        av_add_index_entry(st, pos, dts, size, 0, AVINDEX_KEYFRAME);
365
    break;
366
 }
367

    
368
    // if not streamed and no duration from metadata then seek to end to find the duration from the timestamps
369
    if(!url_is_streamed(s->pb) && s->duration==AV_NOPTS_VALUE){
370
        int size;
371
        const int64_t pos= url_ftell(s->pb);
372
        const int64_t fsize= url_fsize(s->pb);
373
        url_fseek(s->pb, fsize-4, SEEK_SET);
374
        size= get_be32(s->pb);
375
        url_fseek(s->pb, fsize-3-size, SEEK_SET);
376
        if(size == get_be24(s->pb) + 11){
377
            uint32_t ts = get_be24(s->pb);
378
            ts |= get_byte(s->pb) << 24;
379
            s->duration = ts * (int64_t)AV_TIME_BASE / 1000;
380
        }
381
        url_fseek(s->pb, pos, SEEK_SET);
382
    }
383

    
384
    if(is_audio){
385
        if(!st->codec->channels || !st->codec->sample_rate || !st->codec->bits_per_coded_sample) {
386
            st->codec->channels = (flags & FLV_AUDIO_CHANNEL_MASK) == FLV_STEREO ? 2 : 1;
387
            st->codec->sample_rate = (44100 << ((flags & FLV_AUDIO_SAMPLERATE_MASK) >> FLV_AUDIO_SAMPLERATE_OFFSET) >> 3);
388
            st->codec->bits_per_coded_sample = (flags & FLV_AUDIO_SAMPLESIZE_MASK) ? 16 : 8;
389
        }
390
        if(!st->codec->codec_id){
391
            flv_set_audio_codec(s, st, flags & FLV_AUDIO_CODECID_MASK);
392
        }
393
    }else{
394
        size -= flv_set_video_codec(s, st, flags & FLV_VIDEO_CODECID_MASK);
395
    }
396

    
397
    if (st->codec->codec_id == CODEC_ID_AAC ||
398
        st->codec->codec_id == CODEC_ID_H264) {
399
        int type = get_byte(s->pb);
400
        size--;
401
        if (st->codec->codec_id == CODEC_ID_H264) {
402
            int32_t cts = (get_be24(s->pb)+0xff800000)^0xff800000; // sign extension
403
            pts = dts + cts;
404
            if (cts < 0) { // dts are wrong
405
                flv->wrong_dts = 1;
406
                av_log(s, AV_LOG_WARNING, "negative cts, previous timestamps might be wrong\n");
407
            }
408
            if (flv->wrong_dts)
409
                dts = AV_NOPTS_VALUE;
410
        }
411
        if (type == 0) {
412
            if ((ret = flv_get_extradata(s, st, size)) < 0)
413
                return ret;
414
            if (st->codec->codec_id == CODEC_ID_AAC) {
415
                MPEG4AudioConfig cfg;
416
                ff_mpeg4audio_get_config(&cfg, st->codec->extradata,
417
                                         st->codec->extradata_size);
418
                st->codec->channels = cfg.channels;
419
                st->codec->sample_rate = cfg.sample_rate;
420
                dprintf(s, "mp4a config channels %d sample rate %d\n",
421
                        st->codec->channels, st->codec->sample_rate);
422
            }
423

    
424
            return AVERROR(EAGAIN);
425
        }
426
    }
427

    
428
    /* skip empty data packets */
429
    if (!size)
430
        return AVERROR(EAGAIN);
431

    
432
    ret= av_get_packet(s->pb, pkt, size);
433
    if (ret < 0) {
434
        return AVERROR(EIO);
435
    }
436
    /* note: we need to modify the packet size here to handle the last
437
       packet */
438
    pkt->size = ret;
439
    pkt->dts = dts;
440
    pkt->pts = pts == AV_NOPTS_VALUE ? dts : pts;
441
    pkt->stream_index = st->index;
442

    
443
    if (is_audio || ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY))
444
        pkt->flags |= PKT_FLAG_KEY;
445

    
446
    return ret;
447
}
448

    
449
AVInputFormat flv_demuxer = {
450
    "flv",
451
    NULL_IF_CONFIG_SMALL("FLV format"),
452
    sizeof(FLVContext),
453
    flv_probe,
454
    flv_read_header,
455
    flv_read_packet,
456
    .extensions = "flv",
457
    .value = CODEC_ID_FLV1,
458
};