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ffmpeg / libavformat / flvdec.c @ f96d0eef

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1
/*
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 * FLV demuxer
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 * Copyright (c) 2003 The FFmpeg Project.
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 *
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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
static int flv_probe(AVProbeData *p)
30
{
31
    const uint8_t *d;
32

    
33
    d = p->buf;
34
    if (d[0] == 'F' && d[1] == 'L' && d[2] == 'V' && d[3] < 5 && d[5]==0) {
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        return AVPROBE_SCORE_MAX;
36
    }
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    return 0;
38
}
39

    
40
static void flv_set_audio_codec(AVFormatContext *s, AVStream *astream, int flv_codecid) {
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    AVCodecContext *acodec = astream->codec;
42
    switch(flv_codecid) {
43
        //no distinction between S16 and S8 PCM codec flags
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        case FLV_CODECID_PCM:
45
            acodec->codec_id = acodec->bits_per_coded_sample == 8 ? CODEC_ID_PCM_S8 :
46
#ifdef WORDS_BIGENDIAN
47
                                CODEC_ID_PCM_S16BE;
48
#else
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                                CODEC_ID_PCM_S16LE;
50
#endif
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            break;
52
        case FLV_CODECID_PCM_LE:
53
            acodec->codec_id = acodec->bits_per_coded_sample == 8 ? CODEC_ID_PCM_S8 : CODEC_ID_PCM_S16LE; break;
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        case FLV_CODECID_AAC  : acodec->codec_id = CODEC_ID_AAC;                                    break;
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        case FLV_CODECID_ADPCM: acodec->codec_id = CODEC_ID_ADPCM_SWF;                              break;
56
        case FLV_CODECID_SPEEX:
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            acodec->codec_id = CODEC_ID_SPEEX;
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            acodec->sample_rate = 16000;
59
            break;
60
        case FLV_CODECID_MP3  : acodec->codec_id = CODEC_ID_MP3      ; astream->need_parsing = AVSTREAM_PARSE_FULL; break;
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        case FLV_CODECID_NELLYMOSER_8KHZ_MONO:
62
            acodec->sample_rate = 8000; //in case metadata does not otherwise declare samplerate
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        case FLV_CODECID_NELLYMOSER:
64
            acodec->codec_id = CODEC_ID_NELLYMOSER;
65
            break;
66
        default:
67
            av_log(s, AV_LOG_INFO, "Unsupported audio codec (%x)\n", flv_codecid >> FLV_AUDIO_CODECID_OFFSET);
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            acodec->codec_tag = flv_codecid >> FLV_AUDIO_CODECID_OFFSET;
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    }
70
}
71

    
72
static int flv_set_video_codec(AVFormatContext *s, AVStream *vstream, int flv_codecid) {
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    AVCodecContext *vcodec = vstream->codec;
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    switch(flv_codecid) {
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        case FLV_CODECID_H263  : vcodec->codec_id = CODEC_ID_FLV1   ; break;
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        case FLV_CODECID_SCREEN: vcodec->codec_id = CODEC_ID_FLASHSV; break;
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        case FLV_CODECID_VP6   : vcodec->codec_id = CODEC_ID_VP6F   ;
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        case FLV_CODECID_VP6A  :
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            if(flv_codecid == FLV_CODECID_VP6A)
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                vcodec->codec_id = CODEC_ID_VP6A;
81
            if(vcodec->extradata_size != 1) {
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                vcodec->extradata_size = 1;
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                vcodec->extradata = av_malloc(1);
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            }
85
            vcodec->extradata[0] = get_byte(s->pb);
86
            return 1; // 1 byte body size adjustment for flv_read_packet()
87
        case FLV_CODECID_H264:
88
            vcodec->codec_id = CODEC_ID_H264;
89
            return 3; // not 4, reading packet type will consume one byte
90
        default:
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            av_log(s, AV_LOG_INFO, "Unsupported video codec (%x)\n", flv_codecid);
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            vcodec->codec_tag = flv_codecid;
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    }
94

    
95
    return 0;
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}
97

    
98
static int amf_get_string(ByteIOContext *ioc, char *buffer, int buffsize) {
99
    int length = get_be16(ioc);
100
    if(length >= buffsize) {
101
        url_fskip(ioc, length);
102
        return -1;
103
    }
104

    
105
    get_buffer(ioc, buffer, length);
106

    
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    buffer[length] = '\0';
108

    
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    return length;
110
}
111

    
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static int amf_parse_object(AVFormatContext *s, AVStream *astream, AVStream *vstream, const char *key, int64_t max_pos, int depth) {
113
    AVCodecContext *acodec, *vcodec;
114
    ByteIOContext *ioc;
115
    AMFDataType amf_type;
116
    char str_val[256];
117
    double num_val;
118

    
119
    num_val = 0;
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    ioc = s->pb;
121

    
122
    amf_type = get_byte(ioc);
123

    
124
    switch(amf_type) {
125
        case AMF_DATA_TYPE_NUMBER:
126
            num_val = av_int2dbl(get_be64(ioc)); break;
127
        case AMF_DATA_TYPE_BOOL:
128
            num_val = get_byte(ioc); break;
129
        case AMF_DATA_TYPE_STRING:
130
            if(amf_get_string(ioc, str_val, sizeof(str_val)) < 0)
131
                return -1;
132
            break;
133
        case AMF_DATA_TYPE_OBJECT: {
134
            unsigned int keylen;
135

    
136
            while(url_ftell(ioc) < max_pos - 2 && (keylen = get_be16(ioc))) {
137
                url_fskip(ioc, keylen); //skip key string
138
                if(amf_parse_object(s, NULL, NULL, NULL, max_pos, depth + 1) < 0)
139
                    return -1; //if we couldn't skip, bomb out.
140
            }
141
            if(get_byte(ioc) != AMF_END_OF_OBJECT)
142
                return -1;
143
        }
144
            break;
145
        case AMF_DATA_TYPE_NULL:
146
        case AMF_DATA_TYPE_UNDEFINED:
147
        case AMF_DATA_TYPE_UNSUPPORTED:
148
            break; //these take up no additional space
149
        case AMF_DATA_TYPE_MIXEDARRAY:
150
            url_fskip(ioc, 4); //skip 32-bit max array index
151
            while(url_ftell(ioc) < max_pos - 2 && amf_get_string(ioc, str_val, sizeof(str_val)) > 0) {
152
                //this is the only case in which we would want a nested parse to not skip over the object
153
                if(amf_parse_object(s, astream, vstream, str_val, max_pos, depth + 1) < 0)
154
                    return -1;
155
            }
156
            if(get_byte(ioc) != AMF_END_OF_OBJECT)
157
                return -1;
158
            break;
159
        case AMF_DATA_TYPE_ARRAY: {
160
            unsigned int arraylen, i;
161

    
162
            arraylen = get_be32(ioc);
163
            for(i = 0; i < arraylen && url_ftell(ioc) < max_pos - 1; i++) {
164
                if(amf_parse_object(s, NULL, NULL, NULL, max_pos, depth + 1) < 0)
165
                    return -1; //if we couldn't skip, bomb out.
166
            }
167
        }
168
            break;
169
        case AMF_DATA_TYPE_DATE:
170
            url_fskip(ioc, 8 + 2); //timestamp (double) and UTC offset (int16)
171
            break;
172
        default: //unsupported type, we couldn't skip
173
            return -1;
174
    }
175

    
176
    if(depth == 1 && key) { //only look for metadata values when we are not nested and key != NULL
177
        acodec = astream ? astream->codec : NULL;
178
        vcodec = vstream ? vstream->codec : NULL;
179

    
180
        if(amf_type == AMF_DATA_TYPE_BOOL) {
181
            if(!strcmp(key, "stereo") && acodec) acodec->channels = num_val > 0 ? 2 : 1;
182
        } else if(amf_type == AMF_DATA_TYPE_NUMBER) {
183
            if(!strcmp(key, "duration")) s->duration = num_val * AV_TIME_BASE;
184
//            else if(!strcmp(key, "width")  && vcodec && num_val > 0) vcodec->width  = num_val;
185
//            else if(!strcmp(key, "height") && vcodec && num_val > 0) vcodec->height = num_val;
186
            else if(!strcmp(key, "audiocodecid") && acodec && 0 <= (int)num_val)
187
                flv_set_audio_codec(s, astream, (int)num_val << FLV_AUDIO_CODECID_OFFSET);
188
            else if(!strcmp(key, "videocodecid") && vcodec && 0 <= (int)num_val)
189
                flv_set_video_codec(s, vstream, (int)num_val);
190
            else if(!strcmp(key, "audiosamplesize") && acodec && 0 < (int)num_val) {
191
                acodec->bits_per_coded_sample = num_val;
192
                //we may have to rewrite a previously read codecid because FLV only marks PCM endianness.
193
                if(num_val == 8 && (acodec->codec_id == CODEC_ID_PCM_S16BE || acodec->codec_id == CODEC_ID_PCM_S16LE))
194
                    acodec->codec_id = CODEC_ID_PCM_S8;
195
            }
196
            else if(!strcmp(key, "audiosamplerate") && acodec && num_val >= 0) {
197
                //some tools, like FLVTool2, write consistently approximate metadata sample rates
198
                if (!acodec->sample_rate) {
199
                    switch((int)num_val) {
200
                        case 44000: acodec->sample_rate = 44100  ; break;
201
                        case 22000: acodec->sample_rate = 22050  ; break;
202
                        case 11000: acodec->sample_rate = 11025  ; break;
203
                        case 5000 : acodec->sample_rate = 5512   ; break;
204
                        default   : acodec->sample_rate = num_val;
205
                    }
206
                }
207
            }
208
        }
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
    ByteIOContext *ioc;
218
    int i, keylen;
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
    keylen = 0;
224
    ioc = s->pb;
225

    
226
    //first object needs to be "onMetaData" string
227
    type = get_byte(ioc);
228
    if(type != AMF_DATA_TYPE_STRING || amf_get_string(ioc, buffer, sizeof(buffer)) < 0 || strcmp(buffer, "onMetaData"))
229
        return -1;
230

    
231
    //find the streams now so that amf_parse_object doesn't need to do the lookup every time it is called.
232
    for(i = 0; i < s->nb_streams; i++) {
233
        stream = s->streams[i];
234
        if     (stream->codec->codec_type == CODEC_TYPE_AUDIO) astream = stream;
235
        else if(stream->codec->codec_type == CODEC_TYPE_VIDEO) vstream = stream;
236
    }
237

    
238
    //parse the second object (we want a mixed array)
239
    if(amf_parse_object(s, astream, vstream, buffer, next_pos, 0) < 0)
240
        return -1;
241

    
242
    return 0;
243
}
244

    
245
static AVStream *create_stream(AVFormatContext *s, int is_audio){
246
    AVStream *st = av_new_stream(s, is_audio);
247
    if (!st)
248
        return NULL;
249
    st->codec->codec_type = is_audio ? CODEC_TYPE_AUDIO : CODEC_TYPE_VIDEO;
250
    av_set_pts_info(st, 32, 1, 1000); /* 32 bit pts in ms */
251
    return st;
252
}
253

    
254
static int flv_read_header(AVFormatContext *s,
255
                           AVFormatParameters *ap)
256
{
257
    int offset, flags;
258

    
259
    url_fskip(s->pb, 4);
260
    flags = get_byte(s->pb);
261
    /* old flvtool cleared this field */
262
    /* FIXME: better fix needed */
263
    if (!flags) {
264
        flags = FLV_HEADER_FLAG_HASVIDEO | FLV_HEADER_FLAG_HASAUDIO;
265
        av_log(s, AV_LOG_WARNING, "Broken FLV file, which says no streams present, this might fail\n");
266
    }
267

    
268
    if((flags & (FLV_HEADER_FLAG_HASVIDEO|FLV_HEADER_FLAG_HASAUDIO))
269
             != (FLV_HEADER_FLAG_HASVIDEO|FLV_HEADER_FLAG_HASAUDIO))
270
        s->ctx_flags |= AVFMTCTX_NOHEADER;
271

    
272
    if(flags & FLV_HEADER_FLAG_HASVIDEO){
273
        if(!create_stream(s, 0))
274
            return AVERROR(ENOMEM);
275
    }
276
    if(flags & FLV_HEADER_FLAG_HASAUDIO){
277
        if(!create_stream(s, 1))
278
            return AVERROR(ENOMEM);
279
    }
280

    
281
    offset = get_be32(s->pb);
282
    url_fseek(s->pb, offset, SEEK_SET);
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
    get_buffer(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
    int ret, i, type, size, flags, is_audio;
303
    int64_t next, pos;
304
    unsigned dts;
305
    AVStream *st = NULL;
306

    
307
 retry:
308
 for(;;){
309
    pos = url_ftell(s->pb);
310
    url_fskip(s->pb, 4); /* size of previous packet */
311
    type = get_byte(s->pb);
312
    size = get_be24(s->pb);
313
    dts = get_be24(s->pb);
314
    dts |= get_byte(s->pb) << 24;
315
//    av_log(s, AV_LOG_DEBUG, "type:%d, size:%d, dts:%d\n", type, size, dts);
316
    if (url_feof(s->pb))
317
        return AVERROR(EIO);
318
    url_fskip(s->pb, 3); /* stream id, always 0 */
319
    flags = 0;
320

    
321
    if(size == 0)
322
        continue;
323

    
324
    next= size + url_ftell(s->pb);
325

    
326
    if (type == FLV_TAG_TYPE_AUDIO) {
327
        is_audio=1;
328
        flags = get_byte(s->pb);
329
        size--;
330
    } else if (type == FLV_TAG_TYPE_VIDEO) {
331
        is_audio=0;
332
        flags = get_byte(s->pb);
333
        size--;
334
        if ((flags & 0xf0) == 0x50) /* video info / command frame */
335
            goto skip;
336
    } else {
337
        if (type == FLV_TAG_TYPE_META && size > 13+1+4)
338
            flv_read_metabody(s, next);
339
        else /* skip packet */
340
            av_log(s, AV_LOG_ERROR, "skipping flv packet: type %d, size %d, flags %d\n", type, size, flags);
341
    skip:
342
        url_fseek(s->pb, next, SEEK_SET);
343
        continue;
344
    }
345

    
346
    /* skip empty data packets */
347
    if (!size)
348
        continue;
349

    
350
    /* now find stream */
351
    for(i=0;i<s->nb_streams;i++) {
352
        st = s->streams[i];
353
        if (st->id == is_audio)
354
            break;
355
    }
356
    if(i == s->nb_streams){
357
        av_log(NULL, AV_LOG_ERROR, "invalid stream\n");
358
        st= create_stream(s, is_audio);
359
        s->ctx_flags &= ~AVFMTCTX_NOHEADER;
360
    }
361
//    av_log(NULL, AV_LOG_DEBUG, "%d %X %d \n", is_audio, flags, st->discard);
362
    if(  (st->discard >= AVDISCARD_NONKEY && !((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY ||         is_audio))
363
       ||(st->discard >= AVDISCARD_BIDIR  &&  ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_DISP_INTER && !is_audio))
364
       || st->discard >= AVDISCARD_ALL
365
       ){
366
        url_fseek(s->pb, next, SEEK_SET);
367
        continue;
368
    }
369
    if ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY)
370
        av_add_index_entry(st, pos, dts, size, 0, AVINDEX_KEYFRAME);
371
    break;
372
 }
373

    
374
    // if not streamed and no duration from metadata then seek to end to find the duration from the timestamps
375
    if(!url_is_streamed(s->pb) && s->duration==AV_NOPTS_VALUE){
376
        int size;
377
        const int64_t pos= url_ftell(s->pb);
378
        const int64_t fsize= url_fsize(s->pb);
379
        url_fseek(s->pb, fsize-4, SEEK_SET);
380
        size= get_be32(s->pb);
381
        url_fseek(s->pb, fsize-3-size, SEEK_SET);
382
        if(size == get_be24(s->pb) + 11){
383
            s->duration= get_be24(s->pb) * (int64_t)AV_TIME_BASE / 1000;
384
        }
385
        url_fseek(s->pb, pos, SEEK_SET);
386
    }
387

    
388
    if(is_audio){
389
        if(!st->codec->sample_rate || !st->codec->bits_per_coded_sample || (!st->codec->codec_id && !st->codec->codec_tag)) {
390
            st->codec->channels = (flags & FLV_AUDIO_CHANNEL_MASK) == FLV_STEREO ? 2 : 1;
391
            if((flags & FLV_AUDIO_CODECID_MASK) == FLV_CODECID_NELLYMOSER_8KHZ_MONO)
392
                st->codec->sample_rate= 8000;
393
            else
394
                st->codec->sample_rate = (44100 << ((flags & FLV_AUDIO_SAMPLERATE_MASK) >> FLV_AUDIO_SAMPLERATE_OFFSET) >> 3);
395
            st->codec->bits_per_coded_sample = (flags & FLV_AUDIO_SAMPLESIZE_MASK) ? 16 : 8;
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 = get_byte(s->pb);
405
        size--;
406
        if (st->codec->codec_id == CODEC_ID_H264) {
407
            // cts offset ignored because it might to be signed
408
            // and would cause pts < dts
409
            get_be24(s->pb);
410
        }
411
        if (type == 0) {
412
            if ((ret = flv_get_extradata(s, st, size)) < 0)
413
                return ret;
414
            goto retry;
415
        }
416
    }
417

    
418
    ret= av_get_packet(s->pb, pkt, size);
419
    if (ret <= 0) {
420
        return AVERROR(EIO);
421
    }
422
    /* note: we need to modify the packet size here to handle the last
423
       packet */
424
    pkt->size = ret;
425
    pkt->dts = dts;
426
    pkt->stream_index = st->index;
427

    
428
    if (is_audio || ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY))
429
        pkt->flags |= PKT_FLAG_KEY;
430

    
431
    return ret;
432
}
433

    
434
AVInputFormat flv_demuxer = {
435
    "flv",
436
    NULL_IF_CONFIG_SMALL("FLV format"),
437
    0,
438
    flv_probe,
439
    flv_read_header,
440
    flv_read_packet,
441
    .extensions = "flv",
442
    .value = CODEC_ID_FLV1,
443
};