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ffmpeg / libavformat / flvdec.c @ 72415b2a

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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:
7
 *  - 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_U8 :
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_U8 : 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 *buffer, int buffsize) {
108
    int length = get_be16(ioc);
109
    if(length >= buffsize) {
110
        url_fskip(ioc, length);
111
        return -1;
112
    }
113

    
114
    get_buffer(ioc, buffer, length);
115

    
116
    buffer[length] = '\0';
117

    
118
    return length;
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_val[256];
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_val, sizeof(str_val)) < 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_val, sizeof(str_val)) > 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_val, max_pos, depth + 1) < 0)
163
                    return -1;
164
            }
165
            if(get_byte(ioc) != AMF_END_OF_OBJECT)
166
                return -1;
167
            break;
168
        case AMF_DATA_TYPE_ARRAY: {
169
            unsigned int arraylen, i;
170

    
171
            arraylen = get_be32(ioc);
172
            for(i = 0; i < arraylen && url_ftell(ioc) < max_pos - 1; i++) {
173
                if(amf_parse_object(s, NULL, NULL, NULL, max_pos, depth + 1) < 0)
174
                    return -1; //if we couldn't skip, bomb out.
175
            }
176
        }
177
            break;
178
        case AMF_DATA_TYPE_DATE:
179
            url_fskip(ioc, 8 + 2); //timestamp (double) and UTC offset (int16)
180
            break;
181
        default: //unsupported type, we couldn't skip
182
            return -1;
183
    }
184

    
185
    if(depth == 1 && key) { //only look for metadata values when we are not nested and key != NULL
186
        acodec = astream ? astream->codec : NULL;
187
        vcodec = vstream ? vstream->codec : NULL;
188

    
189
        if(amf_type == AMF_DATA_TYPE_BOOL) {
190
            av_strlcpy(str_val, num_val > 0 ? "true" : "false", sizeof(str_val));
191
            av_metadata_set(&s->metadata, key, str_val);
192
        } else if(amf_type == AMF_DATA_TYPE_NUMBER) {
193
            snprintf(str_val, sizeof(str_val), "%.f", num_val);
194
            av_metadata_set(&s->metadata, key, str_val);
195
            if(!strcmp(key, "duration")) s->duration = num_val * AV_TIME_BASE;
196
            else if(!strcmp(key, "videodatarate") && vcodec && 0 <= (int)(num_val * 1024.0))
197
                vcodec->bit_rate = num_val * 1024.0;
198
        } else if (amf_type == AMF_DATA_TYPE_STRING)
199
          av_metadata_set(&s->metadata, key, str_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 buffer[11]; //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 || amf_get_string(ioc, buffer, sizeof(buffer)) < 0 || strcmp(buffer, "onMetaData"))
219
        return -1;
220

    
221
    //find the streams now so that amf_parse_object doesn't need to do the lookup every time it is called.
222
    for(i = 0; i < s->nb_streams; i++) {
223
        stream = s->streams[i];
224
        if     (stream->codec->codec_type == AVMEDIA_TYPE_AUDIO) astream = stream;
225
        else if(stream->codec->codec_type == AVMEDIA_TYPE_VIDEO) vstream = stream;
226
    }
227

    
228
    //parse the second object (we want a mixed array)
229
    if(amf_parse_object(s, astream, vstream, buffer, next_pos, 0) < 0)
230
        return -1;
231

    
232
    return 0;
233
}
234

    
235
static AVStream *create_stream(AVFormatContext *s, int is_audio){
236
    AVStream *st = av_new_stream(s, is_audio);
237
    if (!st)
238
        return NULL;
239
    st->codec->codec_type = is_audio ? AVMEDIA_TYPE_AUDIO : AVMEDIA_TYPE_VIDEO;
240
    av_set_pts_info(st, 32, 1, 1000); /* 32 bit pts in ms */
241
    return st;
242
}
243

    
244
static int flv_read_header(AVFormatContext *s,
245
                           AVFormatParameters *ap)
246
{
247
    int offset, flags;
248

    
249
    url_fskip(s->pb, 4);
250
    flags = get_byte(s->pb);
251
    /* old flvtool cleared this field */
252
    /* FIXME: better fix needed */
253
    if (!flags) {
254
        flags = FLV_HEADER_FLAG_HASVIDEO | FLV_HEADER_FLAG_HASAUDIO;
255
        av_log(s, AV_LOG_WARNING, "Broken FLV file, which says no streams present, this might fail\n");
256
    }
257

    
258
    if((flags & (FLV_HEADER_FLAG_HASVIDEO|FLV_HEADER_FLAG_HASAUDIO))
259
             != (FLV_HEADER_FLAG_HASVIDEO|FLV_HEADER_FLAG_HASAUDIO))
260
        s->ctx_flags |= AVFMTCTX_NOHEADER;
261

    
262
    if(flags & FLV_HEADER_FLAG_HASVIDEO){
263
        if(!create_stream(s, 0))
264
            return AVERROR(ENOMEM);
265
    }
266
    if(flags & FLV_HEADER_FLAG_HASAUDIO){
267
        if(!create_stream(s, 1))
268
            return AVERROR(ENOMEM);
269
    }
270

    
271
    offset = get_be32(s->pb);
272
    url_fseek(s->pb, offset, SEEK_SET);
273

    
274
    s->start_time = 0;
275

    
276
    return 0;
277
}
278

    
279
static int flv_get_extradata(AVFormatContext *s, AVStream *st, int size)
280
{
281
    av_free(st->codec->extradata);
282
    st->codec->extradata = av_mallocz(size + FF_INPUT_BUFFER_PADDING_SIZE);
283
    if (!st->codec->extradata)
284
        return AVERROR(ENOMEM);
285
    st->codec->extradata_size = size;
286
    get_buffer(s->pb, st->codec->extradata, st->codec->extradata_size);
287
    return 0;
288
}
289

    
290
static int flv_read_packet(AVFormatContext *s, AVPacket *pkt)
291
{
292
    FLVContext *flv = s->priv_data;
293
    int ret, i, type, size, flags, is_audio;
294
    int64_t next, pos;
295
    int64_t dts, pts = AV_NOPTS_VALUE;
296
    AVStream *st = NULL;
297

    
298
 for(;;){
299
    pos = url_ftell(s->pb);
300
    url_fskip(s->pb, 4); /* size of previous packet */
301
    type = get_byte(s->pb);
302
    size = get_be24(s->pb);
303
    dts = get_be24(s->pb);
304
    dts |= get_byte(s->pb) << 24;
305
//    av_log(s, AV_LOG_DEBUG, "type:%d, size:%d, dts:%d\n", type, size, dts);
306
    if (url_feof(s->pb))
307
        return AVERROR_EOF;
308
    url_fskip(s->pb, 3); /* stream id, always 0 */
309
    flags = 0;
310

    
311
    if(size == 0)
312
        continue;
313

    
314
    next= size + url_ftell(s->pb);
315

    
316
    if (type == FLV_TAG_TYPE_AUDIO) {
317
        is_audio=1;
318
        flags = get_byte(s->pb);
319
        size--;
320
    } else if (type == FLV_TAG_TYPE_VIDEO) {
321
        is_audio=0;
322
        flags = get_byte(s->pb);
323
        size--;
324
        if ((flags & 0xf0) == 0x50) /* video info / command frame */
325
            goto skip;
326
    } else {
327
        if (type == FLV_TAG_TYPE_META && size > 13+1+4)
328
            flv_read_metabody(s, next);
329
        else /* skip packet */
330
            av_log(s, AV_LOG_DEBUG, "skipping flv packet: type %d, size %d, flags %d\n", type, size, flags);
331
    skip:
332
        url_fseek(s->pb, next, SEEK_SET);
333
        continue;
334
    }
335

    
336
    /* skip empty data packets */
337
    if (!size)
338
        continue;
339

    
340
    /* now find stream */
341
    for(i=0;i<s->nb_streams;i++) {
342
        st = s->streams[i];
343
        if (st->id == is_audio)
344
            break;
345
    }
346
    if(i == s->nb_streams){
347
        av_log(s, AV_LOG_ERROR, "invalid stream\n");
348
        st= create_stream(s, is_audio);
349
        s->ctx_flags &= ~AVFMTCTX_NOHEADER;
350
    }
351
//    av_log(s, AV_LOG_DEBUG, "%d %X %d \n", is_audio, flags, st->discard);
352
    if(  (st->discard >= AVDISCARD_NONKEY && !((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY ||         is_audio))
353
       ||(st->discard >= AVDISCARD_BIDIR  &&  ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_DISP_INTER && !is_audio))
354
       || st->discard >= AVDISCARD_ALL
355
       ){
356
        url_fseek(s->pb, next, SEEK_SET);
357
        continue;
358
    }
359
    if ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY)
360
        av_add_index_entry(st, pos, dts, size, 0, AVINDEX_KEYFRAME);
361
    break;
362
 }
363

    
364
    // if not streamed and no duration from metadata then seek to end to find the duration from the timestamps
365
    if(!url_is_streamed(s->pb) && (!s->duration || s->duration==AV_NOPTS_VALUE)){
366
        int size;
367
        const int64_t pos= url_ftell(s->pb);
368
        const int64_t fsize= url_fsize(s->pb);
369
        url_fseek(s->pb, fsize-4, SEEK_SET);
370
        size= get_be32(s->pb);
371
        url_fseek(s->pb, fsize-3-size, SEEK_SET);
372
        if(size == get_be24(s->pb) + 11){
373
            uint32_t ts = get_be24(s->pb);
374
            ts |= get_byte(s->pb) << 24;
375
            s->duration = ts * (int64_t)AV_TIME_BASE / 1000;
376
        }
377
        url_fseek(s->pb, pos, SEEK_SET);
378
    }
379

    
380
    if(is_audio){
381
        if(!st->codec->channels || !st->codec->sample_rate || !st->codec->bits_per_coded_sample) {
382
            st->codec->channels = (flags & FLV_AUDIO_CHANNEL_MASK) == FLV_STEREO ? 2 : 1;
383
            st->codec->sample_rate = (44100 << ((flags & FLV_AUDIO_SAMPLERATE_MASK) >> FLV_AUDIO_SAMPLERATE_OFFSET) >> 3);
384
            st->codec->bits_per_coded_sample = (flags & FLV_AUDIO_SAMPLESIZE_MASK) ? 16 : 8;
385
        }
386
        if(!st->codec->codec_id){
387
            flv_set_audio_codec(s, st, flags & FLV_AUDIO_CODECID_MASK);
388
        }
389
    }else{
390
        size -= flv_set_video_codec(s, st, flags & FLV_VIDEO_CODECID_MASK);
391
    }
392

    
393
    if (st->codec->codec_id == CODEC_ID_AAC ||
394
        st->codec->codec_id == CODEC_ID_H264) {
395
        int type = get_byte(s->pb);
396
        size--;
397
        if (st->codec->codec_id == CODEC_ID_H264) {
398
            int32_t cts = (get_be24(s->pb)+0xff800000)^0xff800000; // sign extension
399
            pts = dts + cts;
400
            if (cts < 0) { // dts are wrong
401
                flv->wrong_dts = 1;
402
                av_log(s, AV_LOG_WARNING, "negative cts, previous timestamps might be wrong\n");
403
            }
404
            if (flv->wrong_dts)
405
                dts = AV_NOPTS_VALUE;
406
        }
407
        if (type == 0) {
408
            if ((ret = flv_get_extradata(s, st, size)) < 0)
409
                return ret;
410
            if (st->codec->codec_id == CODEC_ID_AAC) {
411
                MPEG4AudioConfig cfg;
412
                ff_mpeg4audio_get_config(&cfg, st->codec->extradata,
413
                                         st->codec->extradata_size);
414
                st->codec->channels = cfg.channels;
415
                st->codec->sample_rate = cfg.sample_rate;
416
                dprintf(s, "mp4a config channels %d sample rate %d\n",
417
                        st->codec->channels, st->codec->sample_rate);
418
            }
419

    
420
            return AVERROR(EAGAIN);
421
        }
422
    }
423

    
424
    /* skip empty data packets */
425
    if (!size)
426
        return AVERROR(EAGAIN);
427

    
428
    ret= av_get_packet(s->pb, pkt, size);
429
    if (ret < 0) {
430
        return AVERROR(EIO);
431
    }
432
    /* note: we need to modify the packet size here to handle the last
433
       packet */
434
    pkt->size = ret;
435
    pkt->dts = dts;
436
    pkt->pts = pts == AV_NOPTS_VALUE ? dts : pts;
437
    pkt->stream_index = st->index;
438

    
439
    if (is_audio || ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY))
440
        pkt->flags |= PKT_FLAG_KEY;
441

    
442
    return ret;
443
}
444

    
445
AVInputFormat flv_demuxer = {
446
    "flv",
447
    NULL_IF_CONFIG_SMALL("FLV format"),
448
    sizeof(FLVContext),
449
    flv_probe,
450
    flv_read_header,
451
    flv_read_packet,
452
    .extensions = "flv",
453
    .value = CODEC_ID_FLV1,
454
};