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ffmpeg / libavformat / flvdec.c @ 2f3d7ea9

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1
/*
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 * 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.
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 * 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.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * 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
#include "avformat.h"
27
#include "flv.h"
28

    
29
typedef struct {
30
    int wrong_dts; ///< wrong dts due to negative cts
31
} FLVContext;
32

    
33
static int flv_probe(AVProbeData *p)
34
{
35
    const uint8_t *d;
36

    
37
    d = p->buf;
38
    if (d[0] == 'F' && d[1] == 'L' && d[2] == 'V' && d[3] < 5 && d[5]==0) {
39
        return AVPROBE_SCORE_MAX;
40
    }
41
    return 0;
42
}
43

    
44
static void flv_set_audio_codec(AVFormatContext *s, AVStream *astream, int flv_codecid) {
45
    AVCodecContext *acodec = astream->codec;
46
    switch(flv_codecid) {
47
        //no distinction between S16 and S8 PCM codec flags
48
        case FLV_CODECID_PCM:
49
            acodec->codec_id = acodec->bits_per_coded_sample == 8 ? CODEC_ID_PCM_S8 :
50
#ifdef WORDS_BIGENDIAN
51
                                CODEC_ID_PCM_S16BE;
52
#else
53
                                CODEC_ID_PCM_S16LE;
54
#endif
55
            break;
56
        case FLV_CODECID_PCM_LE:
57
            acodec->codec_id = acodec->bits_per_coded_sample == 8 ? CODEC_ID_PCM_S8 : CODEC_ID_PCM_S16LE; break;
58
        case FLV_CODECID_AAC  : acodec->codec_id = CODEC_ID_AAC;                                    break;
59
        case FLV_CODECID_ADPCM: acodec->codec_id = CODEC_ID_ADPCM_SWF;                              break;
60
        case FLV_CODECID_SPEEX:
61
            acodec->codec_id = CODEC_ID_SPEEX;
62
            acodec->sample_rate = 16000;
63
            break;
64
        case FLV_CODECID_MP3  : acodec->codec_id = CODEC_ID_MP3      ; astream->need_parsing = AVSTREAM_PARSE_FULL; break;
65
        case FLV_CODECID_NELLYMOSER_8KHZ_MONO:
66
            acodec->sample_rate = 8000; //in case metadata does not otherwise declare samplerate
67
        case FLV_CODECID_NELLYMOSER:
68
            acodec->codec_id = CODEC_ID_NELLYMOSER;
69
            break;
70
        default:
71
            av_log(s, AV_LOG_INFO, "Unsupported audio codec (%x)\n", flv_codecid >> FLV_AUDIO_CODECID_OFFSET);
72
            acodec->codec_tag = flv_codecid >> FLV_AUDIO_CODECID_OFFSET;
73
    }
74
}
75

    
76
static int flv_set_video_codec(AVFormatContext *s, AVStream *vstream, int flv_codecid) {
77
    AVCodecContext *vcodec = vstream->codec;
78
    switch(flv_codecid) {
79
        case FLV_CODECID_H263  : vcodec->codec_id = CODEC_ID_FLV1   ; break;
80
        case FLV_CODECID_SCREEN: vcodec->codec_id = CODEC_ID_FLASHSV; break;
81
        case FLV_CODECID_VP6   : vcodec->codec_id = CODEC_ID_VP6F   ;
82
        case FLV_CODECID_VP6A  :
83
            if(flv_codecid == FLV_CODECID_VP6A)
84
                vcodec->codec_id = CODEC_ID_VP6A;
85
            if(vcodec->extradata_size != 1) {
86
                vcodec->extradata_size = 1;
87
                vcodec->extradata = av_malloc(1);
88
            }
89
            vcodec->extradata[0] = get_byte(s->pb);
90
            return 1; // 1 byte body size adjustment for flv_read_packet()
91
        case FLV_CODECID_H264:
92
            vcodec->codec_id = CODEC_ID_H264;
93
            return 3; // not 4, reading packet type will consume one byte
94
        default:
95
            av_log(s, AV_LOG_INFO, "Unsupported video codec (%x)\n", flv_codecid);
96
            vcodec->codec_tag = flv_codecid;
97
    }
98

    
99
    return 0;
100
}
101

    
102
static int amf_get_string(ByteIOContext *ioc, char *buffer, int buffsize) {
103
    int length = get_be16(ioc);
104
    if(length >= buffsize) {
105
        url_fskip(ioc, length);
106
        return -1;
107
    }
108

    
109
    get_buffer(ioc, buffer, length);
110

    
111
    buffer[length] = '\0';
112

    
113
    return length;
114
}
115

    
116
static int amf_parse_object(AVFormatContext *s, AVStream *astream, AVStream *vstream, const char *key, int64_t max_pos, int depth) {
117
    AVCodecContext *acodec, *vcodec;
118
    ByteIOContext *ioc;
119
    AMFDataType amf_type;
120
    char str_val[256];
121
    double num_val;
122

    
123
    num_val = 0;
124
    ioc = s->pb;
125

    
126
    amf_type = get_byte(ioc);
127

    
128
    switch(amf_type) {
129
        case AMF_DATA_TYPE_NUMBER:
130
            num_val = av_int2dbl(get_be64(ioc)); break;
131
        case AMF_DATA_TYPE_BOOL:
132
            num_val = get_byte(ioc); break;
133
        case AMF_DATA_TYPE_STRING:
134
            if(amf_get_string(ioc, str_val, sizeof(str_val)) < 0)
135
                return -1;
136
            break;
137
        case AMF_DATA_TYPE_OBJECT: {
138
            unsigned int keylen;
139

    
140
            while(url_ftell(ioc) < max_pos - 2 && (keylen = get_be16(ioc))) {
141
                url_fskip(ioc, keylen); //skip key string
142
                if(amf_parse_object(s, NULL, NULL, NULL, max_pos, depth + 1) < 0)
143
                    return -1; //if we couldn't skip, bomb out.
144
            }
145
            if(get_byte(ioc) != AMF_END_OF_OBJECT)
146
                return -1;
147
        }
148
            break;
149
        case AMF_DATA_TYPE_NULL:
150
        case AMF_DATA_TYPE_UNDEFINED:
151
        case AMF_DATA_TYPE_UNSUPPORTED:
152
            break; //these take up no additional space
153
        case AMF_DATA_TYPE_MIXEDARRAY:
154
            url_fskip(ioc, 4); //skip 32-bit max array index
155
            while(url_ftell(ioc) < max_pos - 2 && amf_get_string(ioc, str_val, sizeof(str_val)) > 0) {
156
                //this is the only case in which we would want a nested parse to not skip over the object
157
                if(amf_parse_object(s, astream, vstream, str_val, max_pos, depth + 1) < 0)
158
                    return -1;
159
            }
160
            if(get_byte(ioc) != AMF_END_OF_OBJECT)
161
                return -1;
162
            break;
163
        case AMF_DATA_TYPE_ARRAY: {
164
            unsigned int arraylen, i;
165

    
166
            arraylen = get_be32(ioc);
167
            for(i = 0; i < arraylen && url_ftell(ioc) < max_pos - 1; i++) {
168
                if(amf_parse_object(s, NULL, NULL, NULL, max_pos, depth + 1) < 0)
169
                    return -1; //if we couldn't skip, bomb out.
170
            }
171
        }
172
            break;
173
        case AMF_DATA_TYPE_DATE:
174
            url_fskip(ioc, 8 + 2); //timestamp (double) and UTC offset (int16)
175
            break;
176
        default: //unsupported type, we couldn't skip
177
            return -1;
178
    }
179

    
180
    if(depth == 1 && key) { //only look for metadata values when we are not nested and key != NULL
181
        acodec = astream ? astream->codec : NULL;
182
        vcodec = vstream ? vstream->codec : NULL;
183

    
184
        if(amf_type == AMF_DATA_TYPE_BOOL) {
185
            if(!strcmp(key, "stereo") && acodec) acodec->channels = num_val > 0 ? 2 : 1;
186
        } else if(amf_type == AMF_DATA_TYPE_NUMBER) {
187
            if(!strcmp(key, "duration")) s->duration = num_val * AV_TIME_BASE;
188
//            else if(!strcmp(key, "width")  && vcodec && num_val > 0) vcodec->width  = num_val;
189
//            else if(!strcmp(key, "height") && vcodec && num_val > 0) vcodec->height = num_val;
190
            else if(!strcmp(key, "audiocodecid") && acodec && 0 <= (int)num_val)
191
                flv_set_audio_codec(s, astream, (int)num_val << FLV_AUDIO_CODECID_OFFSET);
192
            else if(!strcmp(key, "videocodecid") && vcodec && 0 <= (int)num_val)
193
                flv_set_video_codec(s, vstream, (int)num_val);
194
            else if(!strcmp(key, "audiosamplesize") && acodec && 0 < (int)num_val) {
195
                acodec->bits_per_coded_sample = num_val;
196
                //we may have to rewrite a previously read codecid because FLV only marks PCM endianness.
197
                if(num_val == 8 && (acodec->codec_id == CODEC_ID_PCM_S16BE || acodec->codec_id == CODEC_ID_PCM_S16LE))
198
                    acodec->codec_id = CODEC_ID_PCM_S8;
199
            }
200
            else if(!strcmp(key, "audiosamplerate") && acodec && num_val >= 0) {
201
                //some tools, like FLVTool2, write consistently approximate metadata sample rates
202
                if (!acodec->sample_rate) {
203
                    switch((int)num_val) {
204
                        case 44000: acodec->sample_rate = 44100  ; break;
205
                        case 22000: acodec->sample_rate = 22050  ; break;
206
                        case 11000: acodec->sample_rate = 11025  ; break;
207
                        case 5000 : acodec->sample_rate = 5512   ; break;
208
                        default   : acodec->sample_rate = num_val;
209
                    }
210
                }
211
            }
212
        }
213
    }
214

    
215
    return 0;
216
}
217

    
218
static int flv_read_metabody(AVFormatContext *s, int64_t next_pos) {
219
    AMFDataType type;
220
    AVStream *stream, *astream, *vstream;
221
    ByteIOContext *ioc;
222
    int i, keylen;
223
    char buffer[11]; //only needs to hold the string "onMetaData". Anything longer is something we don't want.
224

    
225
    astream = NULL;
226
    vstream = NULL;
227
    keylen = 0;
228
    ioc = s->pb;
229

    
230
    //first object needs to be "onMetaData" string
231
    type = get_byte(ioc);
232
    if(type != AMF_DATA_TYPE_STRING || amf_get_string(ioc, buffer, sizeof(buffer)) < 0 || strcmp(buffer, "onMetaData"))
233
        return -1;
234

    
235
    //find the streams now so that amf_parse_object doesn't need to do the lookup every time it is called.
236
    for(i = 0; i < s->nb_streams; i++) {
237
        stream = s->streams[i];
238
        if     (stream->codec->codec_type == CODEC_TYPE_AUDIO) astream = stream;
239
        else if(stream->codec->codec_type == CODEC_TYPE_VIDEO) vstream = stream;
240
    }
241

    
242
    //parse the second object (we want a mixed array)
243
    if(amf_parse_object(s, astream, vstream, buffer, next_pos, 0) < 0)
244
        return -1;
245

    
246
    return 0;
247
}
248

    
249
static AVStream *create_stream(AVFormatContext *s, int is_audio){
250
    AVStream *st = av_new_stream(s, is_audio);
251
    if (!st)
252
        return NULL;
253
    st->codec->codec_type = is_audio ? CODEC_TYPE_AUDIO : CODEC_TYPE_VIDEO;
254
    av_set_pts_info(st, 32, 1, 1000); /* 32 bit pts in ms */
255
    return st;
256
}
257

    
258
static int flv_read_header(AVFormatContext *s,
259
                           AVFormatParameters *ap)
260
{
261
    int offset, flags;
262

    
263
    url_fskip(s->pb, 4);
264
    flags = get_byte(s->pb);
265
    /* old flvtool cleared this field */
266
    /* FIXME: better fix needed */
267
    if (!flags) {
268
        flags = FLV_HEADER_FLAG_HASVIDEO | FLV_HEADER_FLAG_HASAUDIO;
269
        av_log(s, AV_LOG_WARNING, "Broken FLV file, which says no streams present, this might fail\n");
270
    }
271

    
272
    if((flags & (FLV_HEADER_FLAG_HASVIDEO|FLV_HEADER_FLAG_HASAUDIO))
273
             != (FLV_HEADER_FLAG_HASVIDEO|FLV_HEADER_FLAG_HASAUDIO))
274
        s->ctx_flags |= AVFMTCTX_NOHEADER;
275

    
276
    if(flags & FLV_HEADER_FLAG_HASVIDEO){
277
        if(!create_stream(s, 0))
278
            return AVERROR(ENOMEM);
279
    }
280
    if(flags & FLV_HEADER_FLAG_HASAUDIO){
281
        if(!create_stream(s, 1))
282
            return AVERROR(ENOMEM);
283
    }
284

    
285
    offset = get_be32(s->pb);
286
    url_fseek(s->pb, offset, SEEK_SET);
287

    
288
    s->start_time = 0;
289

    
290
    return 0;
291
}
292

    
293
static int flv_get_extradata(AVFormatContext *s, AVStream *st, int size)
294
{
295
    av_free(st->codec->extradata);
296
    st->codec->extradata = av_mallocz(size + FF_INPUT_BUFFER_PADDING_SIZE);
297
    if (!st->codec->extradata)
298
        return AVERROR(ENOMEM);
299
    st->codec->extradata_size = size;
300
    get_buffer(s->pb, st->codec->extradata, st->codec->extradata_size);
301
    return 0;
302
}
303

    
304
static int flv_read_packet(AVFormatContext *s, AVPacket *pkt)
305
{
306
    FLVContext *flv = s->priv_data;
307
    int ret, i, type, size, flags, is_audio;
308
    int64_t next, pos;
309
    int64_t dts, pts = AV_NOPTS_VALUE;
310
    AVStream *st = NULL;
311

    
312
 retry:
313
 for(;;){
314
    pos = url_ftell(s->pb);
315
    url_fskip(s->pb, 4); /* size of previous packet */
316
    type = get_byte(s->pb);
317
    size = get_be24(s->pb);
318
    dts = get_be24(s->pb);
319
    dts |= get_byte(s->pb) << 24;
320
//    av_log(s, AV_LOG_DEBUG, "type:%d, size:%d, dts:%d\n", type, size, dts);
321
    if (url_feof(s->pb))
322
        return AVERROR(EIO);
323
    url_fskip(s->pb, 3); /* stream id, always 0 */
324
    flags = 0;
325

    
326
    if(size == 0)
327
        continue;
328

    
329
    next= size + url_ftell(s->pb);
330

    
331
    if (type == FLV_TAG_TYPE_AUDIO) {
332
        is_audio=1;
333
        flags = get_byte(s->pb);
334
        size--;
335
    } else if (type == FLV_TAG_TYPE_VIDEO) {
336
        is_audio=0;
337
        flags = get_byte(s->pb);
338
        size--;
339
        if ((flags & 0xf0) == 0x50) /* video info / command frame */
340
            goto skip;
341
    } else {
342
        if (type == FLV_TAG_TYPE_META && size > 13+1+4)
343
            flv_read_metabody(s, next);
344
        else /* skip packet */
345
            av_log(s, AV_LOG_ERROR, "skipping flv packet: type %d, size %d, flags %d\n", type, size, flags);
346
    skip:
347
        url_fseek(s->pb, next, SEEK_SET);
348
        continue;
349
    }
350

    
351
    /* skip empty data packets */
352
    if (!size)
353
        continue;
354

    
355
    /* now find stream */
356
    for(i=0;i<s->nb_streams;i++) {
357
        st = s->streams[i];
358
        if (st->id == is_audio)
359
            break;
360
    }
361
    if(i == s->nb_streams){
362
        av_log(NULL, AV_LOG_ERROR, "invalid stream\n");
363
        st= create_stream(s, is_audio);
364
        s->ctx_flags &= ~AVFMTCTX_NOHEADER;
365
    }
366
//    av_log(NULL, AV_LOG_DEBUG, "%d %X %d \n", is_audio, flags, st->discard);
367
    if(  (st->discard >= AVDISCARD_NONKEY && !((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY ||         is_audio))
368
       ||(st->discard >= AVDISCARD_BIDIR  &&  ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_DISP_INTER && !is_audio))
369
       || st->discard >= AVDISCARD_ALL
370
       ){
371
        url_fseek(s->pb, next, SEEK_SET);
372
        continue;
373
    }
374
    if ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY)
375
        av_add_index_entry(st, pos, dts, size, 0, AVINDEX_KEYFRAME);
376
    break;
377
 }
378

    
379
    // if not streamed and no duration from metadata then seek to end to find the duration from the timestamps
380
    if(!url_is_streamed(s->pb) && s->duration==AV_NOPTS_VALUE){
381
        int size;
382
        const int64_t pos= url_ftell(s->pb);
383
        const int64_t fsize= url_fsize(s->pb);
384
        url_fseek(s->pb, fsize-4, SEEK_SET);
385
        size= get_be32(s->pb);
386
        url_fseek(s->pb, fsize-3-size, SEEK_SET);
387
        if(size == get_be24(s->pb) + 11){
388
            s->duration= get_be24(s->pb) * (int64_t)AV_TIME_BASE / 1000;
389
        }
390
        url_fseek(s->pb, pos, SEEK_SET);
391
    }
392

    
393
    if(is_audio){
394
        if(!st->codec->channels || !st->codec->sample_rate || !st->codec->bits_per_coded_sample) {
395
            st->codec->channels = (flags & FLV_AUDIO_CHANNEL_MASK) == FLV_STEREO ? 2 : 1;
396
            st->codec->sample_rate = (44100 << ((flags & FLV_AUDIO_SAMPLERATE_MASK) >> FLV_AUDIO_SAMPLERATE_OFFSET) >> 3);
397
            st->codec->bits_per_coded_sample = (flags & FLV_AUDIO_SAMPLESIZE_MASK) ? 16 : 8;
398
        }
399
        if(!st->codec->codec_id){
400
            flv_set_audio_codec(s, st, flags & FLV_AUDIO_CODECID_MASK);
401
        }
402
    }else{
403
        size -= flv_set_video_codec(s, st, flags & FLV_VIDEO_CODECID_MASK);
404
    }
405

    
406
    if (st->codec->codec_id == CODEC_ID_AAC ||
407
        st->codec->codec_id == CODEC_ID_H264) {
408
        int type = get_byte(s->pb);
409
        size--;
410
        if (st->codec->codec_id == CODEC_ID_H264) {
411
            int32_t cts = (get_be24(s->pb)+0xff800000)^0xff800000; // sign extension
412
            pts = dts + cts;
413
            if (cts < 0) { // dts are wrong
414
                flv->wrong_dts = 1;
415
                av_log(s, AV_LOG_WARNING, "negative cts, previous timestamps might be wrong\n");
416
            }
417
            if (flv->wrong_dts)
418
                dts = AV_NOPTS_VALUE;
419
        }
420
        if (type == 0) {
421
            if ((ret = flv_get_extradata(s, st, size)) < 0)
422
                return ret;
423
            goto retry;
424
        }
425
    }
426

    
427
    ret= av_get_packet(s->pb, pkt, size);
428
    if (ret <= 0) {
429
        return AVERROR(EIO);
430
    }
431
    /* note: we need to modify the packet size here to handle the last
432
       packet */
433
    pkt->size = ret;
434
    pkt->dts = dts;
435
    pkt->pts = pts == AV_NOPTS_VALUE ? dts : pts;
436
    pkt->stream_index = st->index;
437

    
438
    if (is_audio || ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY))
439
        pkt->flags |= PKT_FLAG_KEY;
440

    
441
    return ret;
442
}
443

    
444
AVInputFormat flv_demuxer = {
445
    "flv",
446
    NULL_IF_CONFIG_SMALL("FLV format"),
447
    sizeof(FLVContext),
448
    flv_probe,
449
    flv_read_header,
450
    flv_read_packet,
451
    .extensions = "flv",
452
    .value = CODEC_ID_FLV1,
453
};