Statistics
| Branch: | Revision:

ffmpeg / libavformat / flvdec.c @ 890d2799

History | View | Annotate | Download (14.3 KB)

1
/*
2
 * FLV demuxer
3
 * Copyright (c) 2003 The FFmpeg 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 FFmpeg.
11
 *
12
 * FFmpeg 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
 * FFmpeg is distributed in the hope that it will be useful,
18
 * 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
23
 * License along with FFmpeg; if not, write to the Free Software
24
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
25
 */
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) {
35
        return AVPROBE_SCORE_MAX;
36
    }
37
    return 0;
38
}
39

    
40
static void flv_set_audio_codec(AVFormatContext *s, AVStream *astream, int flv_codecid) {
41
    AVCodecContext *acodec = astream->codec;
42
    switch(flv_codecid) {
43
        //no distinction between S16 and S8 PCM codec flags
44
        case FLV_CODECID_PCM_BE:
45
            acodec->codec_id = acodec->bits_per_sample == 8 ? CODEC_ID_PCM_S8 : CODEC_ID_PCM_S16BE; break;
46
        case FLV_CODECID_PCM_LE:
47
            acodec->codec_id = acodec->bits_per_sample == 8 ? CODEC_ID_PCM_S8 : CODEC_ID_PCM_S16LE; break;
48
        case FLV_CODECID_ADPCM: acodec->codec_id = CODEC_ID_ADPCM_SWF;                              break;
49
        case FLV_CODECID_MP3  : acodec->codec_id = CODEC_ID_MP3      ; astream->need_parsing = AVSTREAM_PARSE_FULL; break;
50
        case FLV_CODECID_NELLYMOSER_8HZ_MONO:
51
            acodec->sample_rate = 8000; //in case metadata does not otherwise declare samplerate
52
        case FLV_CODECID_NELLYMOSER:
53
            acodec->codec_id = CODEC_ID_NELLYMOSER;
54
            break;
55
        default:
56
            av_log(s, AV_LOG_INFO, "Unsupported audio codec (%x)\n", flv_codecid >> FLV_AUDIO_CODECID_OFFSET);
57
            acodec->codec_tag = flv_codecid >> FLV_AUDIO_CODECID_OFFSET;
58
    }
59
}
60

    
61
static int flv_set_video_codec(AVFormatContext *s, AVStream *vstream, int flv_codecid) {
62
    AVCodecContext *vcodec = vstream->codec;
63
    switch(flv_codecid) {
64
        case FLV_CODECID_H263  : vcodec->codec_id = CODEC_ID_FLV1   ; break;
65
        case FLV_CODECID_SCREEN: vcodec->codec_id = CODEC_ID_FLASHSV; break;
66
        case FLV_CODECID_VP6   : vcodec->codec_id = CODEC_ID_VP6F   ;
67
        case FLV_CODECID_VP6A  :
68
            if(flv_codecid == FLV_CODECID_VP6A)
69
                vcodec->codec_id = CODEC_ID_VP6A;
70
            if(vcodec->extradata_size != 1) {
71
                vcodec->extradata_size = 1;
72
                vcodec->extradata = av_malloc(1);
73
            }
74
            vcodec->extradata[0] = get_byte(s->pb);
75
            return 1; // 1 byte body size adjustment for flv_read_packet()
76
        default:
77
            av_log(s, AV_LOG_INFO, "Unsupported video codec (%x)\n", flv_codecid);
78
            vcodec->codec_tag = flv_codecid;
79
    }
80

    
81
    return 0;
82
}
83

    
84
static int amf_get_string(ByteIOContext *ioc, char *buffer, int buffsize) {
85
    int length = get_be16(ioc);
86
    if(length >= buffsize) {
87
        url_fskip(ioc, length);
88
        return -1;
89
    }
90

    
91
    get_buffer(ioc, buffer, length);
92

    
93
    buffer[length] = '\0';
94

    
95
    return length;
96
}
97

    
98
static int amf_parse_object(AVFormatContext *s, AVStream *astream, AVStream *vstream, const char *key, unsigned int max_pos, int depth) {
99
    AVCodecContext *acodec, *vcodec;
100
    ByteIOContext *ioc;
101
    AMFDataType amf_type;
102
    char str_val[256];
103
    double num_val;
104

    
105
    num_val = 0;
106
    ioc = s->pb;
107

    
108
    amf_type = get_byte(ioc);
109

    
110
    switch(amf_type) {
111
        case AMF_DATA_TYPE_NUMBER:
112
            num_val = av_int2dbl(get_be64(ioc)); break;
113
        case AMF_DATA_TYPE_BOOL:
114
            num_val = get_byte(ioc); break;
115
        case AMF_DATA_TYPE_STRING:
116
            if(amf_get_string(ioc, str_val, sizeof(str_val)) < 0)
117
                return -1;
118
            break;
119
        case AMF_DATA_TYPE_OBJECT: {
120
            unsigned int keylen;
121

    
122
            while(url_ftell(ioc) < max_pos - 2 && (keylen = get_be16(ioc))) {
123
                url_fskip(ioc, keylen); //skip key string
124
                if(amf_parse_object(s, NULL, NULL, NULL, max_pos, depth + 1) < 0)
125
                    return -1; //if we couldn't skip, bomb out.
126
            }
127
            if(get_byte(ioc) != AMF_END_OF_OBJECT)
128
                return -1;
129
        }
130
            break;
131
        case AMF_DATA_TYPE_NULL:
132
        case AMF_DATA_TYPE_UNDEFINED:
133
        case AMF_DATA_TYPE_UNSUPPORTED:
134
            break; //these take up no additional space
135
        case AMF_DATA_TYPE_MIXEDARRAY:
136
            url_fskip(ioc, 4); //skip 32-bit max array index
137
            while(url_ftell(ioc) < max_pos - 2 && amf_get_string(ioc, str_val, sizeof(str_val)) > 0) {
138
                //this is the only case in which we would want a nested parse to not skip over the object
139
                if(amf_parse_object(s, astream, vstream, str_val, max_pos, depth + 1) < 0)
140
                    return -1;
141
            }
142
            if(get_byte(ioc) != AMF_END_OF_OBJECT)
143
                return -1;
144
            break;
145
        case AMF_DATA_TYPE_ARRAY: {
146
            unsigned int arraylen, i;
147

    
148
            arraylen = get_be32(ioc);
149
            for(i = 0; i < arraylen && url_ftell(ioc) < max_pos - 1; i++) {
150
                if(amf_parse_object(s, NULL, NULL, NULL, max_pos, depth + 1) < 0)
151
                    return -1; //if we couldn't skip, bomb out.
152
            }
153
        }
154
            break;
155
        case AMF_DATA_TYPE_DATE:
156
            url_fskip(ioc, 8 + 2); //timestamp (double) and UTC offset (int16)
157
            break;
158
        default: //unsupported type, we couldn't skip
159
            return -1;
160
    }
161

    
162
    if(depth == 1 && key) { //only look for metadata values when we are not nested and key != NULL
163
        acodec = astream ? astream->codec : NULL;
164
        vcodec = vstream ? vstream->codec : NULL;
165

    
166
        if(amf_type == AMF_DATA_TYPE_BOOL) {
167
            if(!strcmp(key, "stereo") && acodec) acodec->channels = num_val > 0 ? 2 : 1;
168
        } else if(amf_type == AMF_DATA_TYPE_NUMBER) {
169
            if(!strcmp(key, "duration")) s->duration = num_val * AV_TIME_BASE;
170
//            else if(!strcmp(key, "width")  && vcodec && num_val > 0) vcodec->width  = num_val;
171
//            else if(!strcmp(key, "height") && vcodec && num_val > 0) vcodec->height = num_val;
172
            else if(!strcmp(key, "audiocodecid") && acodec) flv_set_audio_codec(s, astream, (int)num_val << FLV_AUDIO_CODECID_OFFSET);
173
            else if(!strcmp(key, "videocodecid") && vcodec) flv_set_video_codec(s, vstream, (int)num_val);
174
            else if(!strcmp(key, "audiosamplesize") && acodec && num_val >= 0) {
175
                acodec->bits_per_sample = num_val;
176
                //we may have to rewrite a previously read codecid because FLV only marks PCM endianness.
177
                if(num_val == 8 && (acodec->codec_id == CODEC_ID_PCM_S16BE || acodec->codec_id == CODEC_ID_PCM_S16LE))
178
                    acodec->codec_id = CODEC_ID_PCM_S8;
179
            }
180
            else if(!strcmp(key, "audiosamplerate") && acodec && num_val >= 0) {
181
                //some tools, like FLVTool2, write consistently approximate metadata sample rates
182
                switch((int)num_val) {
183
                    case 44000: acodec->sample_rate = 44100  ; break;
184
                    case 22000: acodec->sample_rate = 22050  ; break;
185
                    case 11000: acodec->sample_rate = 11025  ; break;
186
                    case 5000 : acodec->sample_rate = 5512   ; break;
187
                    default   : acodec->sample_rate = num_val;
188
                }
189
            }
190
        }
191
    }
192

    
193
    return 0;
194
}
195

    
196
static int flv_read_metabody(AVFormatContext *s, unsigned int next_pos) {
197
    AMFDataType type;
198
    AVStream *stream, *astream, *vstream;
199
    ByteIOContext *ioc;
200
    int i, keylen;
201
    char buffer[11]; //only needs to hold the string "onMetaData". Anything longer is something we don't want.
202

    
203
    astream = NULL;
204
    vstream = NULL;
205
    keylen = 0;
206
    ioc = s->pb;
207

    
208
    //first object needs to be "onMetaData" string
209
    type = get_byte(ioc);
210
    if(type != AMF_DATA_TYPE_STRING || amf_get_string(ioc, buffer, sizeof(buffer)) < 0 || strcmp(buffer, "onMetaData"))
211
        return -1;
212

    
213
    //find the streams now so that amf_parse_object doesn't need to do the lookup every time it is called.
214
    for(i = 0; i < s->nb_streams; i++) {
215
        stream = s->streams[i];
216
        if     (stream->codec->codec_type == CODEC_TYPE_AUDIO) astream = stream;
217
        else if(stream->codec->codec_type == CODEC_TYPE_VIDEO) vstream = stream;
218
    }
219

    
220
    //parse the second object (we want a mixed array)
221
    if(amf_parse_object(s, astream, vstream, buffer, next_pos, 0) < 0)
222
        return -1;
223

    
224
    return 0;
225
}
226

    
227
static AVStream *create_stream(AVFormatContext *s, int is_audio){
228
    AVStream *st = av_new_stream(s, is_audio);
229
    if (!st)
230
        return NULL;
231
    st->codec->codec_type = is_audio ? CODEC_TYPE_AUDIO : CODEC_TYPE_VIDEO;
232
    av_set_pts_info(st, 24, 1, 1000); /* 24 bit pts in ms */
233
    return st;
234
}
235

    
236
static int flv_read_header(AVFormatContext *s,
237
                           AVFormatParameters *ap)
238
{
239
    int offset, flags;
240

    
241
    url_fskip(s->pb, 4);
242
    flags = get_byte(s->pb);
243
    /* old flvtool cleared this field */
244
    /* FIXME: better fix needed */
245
    if (!flags) {
246
        flags = FLV_HEADER_FLAG_HASVIDEO | FLV_HEADER_FLAG_HASAUDIO;
247
        av_log(s, AV_LOG_WARNING, "Broken FLV file, which says no streams present, this might fail\n");
248
    }
249

    
250
    if(flags & FLV_HEADER_FLAG_HASVIDEO){
251
        if(!create_stream(s, 0))
252
            return AVERROR(ENOMEM);
253
    }
254
    if(flags & FLV_HEADER_FLAG_HASAUDIO){
255
        if(!create_stream(s, 1))
256
            return AVERROR(ENOMEM);
257
    }
258

    
259
    offset = get_be32(s->pb);
260
    url_fseek(s->pb, offset, SEEK_SET);
261

    
262
    s->start_time = 0;
263

    
264
    return 0;
265
}
266

    
267
static int flv_read_packet(AVFormatContext *s, AVPacket *pkt)
268
{
269
    int ret, i, type, size, pts, flags, is_audio, next, pos;
270
    AVStream *st = NULL;
271

    
272
 for(;;){
273
    pos = url_ftell(s->pb);
274
    url_fskip(s->pb, 4); /* size of previous packet */
275
    type = get_byte(s->pb);
276
    size = get_be24(s->pb);
277
    pts = get_be24(s->pb);
278
    pts |= get_byte(s->pb) << 24;
279
//    av_log(s, AV_LOG_DEBUG, "type:%d, size:%d, pts:%d\n", type, size, pts);
280
    if (url_feof(s->pb))
281
        return AVERROR(EIO);
282
    url_fskip(s->pb, 3); /* stream id, always 0 */
283
    flags = 0;
284

    
285
    if(size == 0)
286
        continue;
287

    
288
    next= size + url_ftell(s->pb);
289

    
290
    if (type == FLV_TAG_TYPE_AUDIO) {
291
        is_audio=1;
292
        flags = get_byte(s->pb);
293
    } else if (type == FLV_TAG_TYPE_VIDEO) {
294
        is_audio=0;
295
        flags = get_byte(s->pb);
296
    } else {
297
        if (type == FLV_TAG_TYPE_META && size > 13+1+4)
298
            flv_read_metabody(s, next);
299
        else /* skip packet */
300
            av_log(s, AV_LOG_ERROR, "skipping flv packet: type %d, size %d, flags %d\n", type, size, flags);
301
        url_fseek(s->pb, next, SEEK_SET);
302
        continue;
303
    }
304

    
305
    /* now find stream */
306
    for(i=0;i<s->nb_streams;i++) {
307
        st = s->streams[i];
308
        if (st->id == is_audio)
309
            break;
310
    }
311
    if(i == s->nb_streams){
312
        av_log(NULL, AV_LOG_ERROR, "invalid stream\n");
313
        st= create_stream(s, is_audio);
314
    }
315
//    av_log(NULL, AV_LOG_DEBUG, "%d %X %d \n", is_audio, flags, st->discard);
316
    if(  (st->discard >= AVDISCARD_NONKEY && !((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY ||         is_audio))
317
       ||(st->discard >= AVDISCARD_BIDIR  &&  ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_DISP_INTER && !is_audio))
318
       || st->discard >= AVDISCARD_ALL
319
       ){
320
        url_fseek(s->pb, next, SEEK_SET);
321
        continue;
322
    }
323
    if ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY)
324
        av_add_index_entry(st, pos, pts, size, 0, AVINDEX_KEYFRAME);
325
    break;
326
 }
327

    
328
    // if not streamed and no duration from metadata then seek to end to find the duration from the timestamps
329
    if(!url_is_streamed(s->pb) && s->duration==AV_NOPTS_VALUE){
330
        int size;
331
        const int pos= url_ftell(s->pb);
332
        const int fsize= url_fsize(s->pb);
333
        url_fseek(s->pb, fsize-4, SEEK_SET);
334
        size= get_be32(s->pb);
335
        url_fseek(s->pb, fsize-3-size, SEEK_SET);
336
        if(size == get_be24(s->pb) + 11){
337
            s->duration= get_be24(s->pb) * (int64_t)AV_TIME_BASE / 1000;
338
        }
339
        url_fseek(s->pb, pos, SEEK_SET);
340
    }
341

    
342
    if(is_audio){
343
        if(!st->codec->sample_rate || !st->codec->bits_per_sample || (!st->codec->codec_id && !st->codec->codec_tag)) {
344
            st->codec->channels = (flags & FLV_AUDIO_CHANNEL_MASK) == FLV_STEREO ? 2 : 1;
345
            if((flags & FLV_AUDIO_CODECID_MASK) == FLV_CODECID_NELLYMOSER_8HZ_MONO)
346
                st->codec->sample_rate= 8000;
347
            else
348
                st->codec->sample_rate = (44100 << ((flags & FLV_AUDIO_SAMPLERATE_MASK) >> FLV_AUDIO_SAMPLERATE_OFFSET) >> 3);
349
            st->codec->bits_per_sample = (flags & FLV_AUDIO_SAMPLESIZE_MASK) ? 16 : 8;
350
            flv_set_audio_codec(s, st, flags & FLV_AUDIO_CODECID_MASK);
351
        }
352
    }else{
353
        size -= flv_set_video_codec(s, st, flags & FLV_VIDEO_CODECID_MASK);
354
    }
355

    
356
    ret= av_get_packet(s->pb, pkt, size - 1);
357
    if (ret <= 0) {
358
        return AVERROR(EIO);
359
    }
360
    /* note: we need to modify the packet size here to handle the last
361
       packet */
362
    pkt->size = ret;
363
    pkt->pts = pts;
364
    pkt->stream_index = st->index;
365

    
366
    if (is_audio || ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY))
367
        pkt->flags |= PKT_FLAG_KEY;
368

    
369
    return ret;
370
}
371

    
372
static int flv_read_close(AVFormatContext *s)
373
{
374
    return 0;
375
}
376

    
377
static int flv_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
378
{
379
    AVStream *st = s->streams[stream_index];
380
    int index = av_index_search_timestamp(st, timestamp, flags);
381
    if (index < 0)
382
        return -1;
383
    url_fseek(s->pb, st->index_entries[index].pos, SEEK_SET);
384

    
385
    return 0;
386
}
387

    
388
AVInputFormat flv_demuxer = {
389
    "flv",
390
    "flv format",
391
    0,
392
    flv_probe,
393
    flv_read_header,
394
    flv_read_packet,
395
    flv_read_close,
396
    flv_read_seek,
397
    .extensions = "flv",
398
    .value = CODEC_ID_FLV1,
399
};