aboutsummaryrefslogtreecommitdiffstats
path: root/libavformat/flvdec.c
blob: 01da9e89e0473a8e5863dc5f68ae6db71cf57b35 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
/*
 * FLV demuxer
 * Copyright (c) 2003 The FFmpeg Project.
 *
 * This demuxer will generate a 1 byte extradata for VP6F content.
 * It is composed of:
 *  - upper 4bits: difference between encoded width and visible width
 *  - lower 4bits: difference between encoded height and visible height
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */
#include "avformat.h"
#include "flv.h"

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

static int flv_probe(AVProbeData *p)
{
    const uint8_t *d;

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

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

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

    return 0;
}

static int amf_get_string(ByteIOContext *ioc, char *buffer, int buffsize) {
    int length = get_be16(ioc);
    if(length >= buffsize) {
        url_fskip(ioc, length);
        return -1;
    }

    get_buffer(ioc, buffer, length);

    buffer[length] = '\0';

    return length;
}

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

    num_val = 0;
    ioc = s->pb;

    amf_type = get_byte(ioc);

    switch(amf_type) {
        case AMF_DATA_TYPE_NUMBER:
            num_val = av_int2dbl(get_be64(ioc)); break;
        case AMF_DATA_TYPE_BOOL:
            num_val = get_byte(ioc); break;
        case AMF_DATA_TYPE_STRING:
            if(amf_get_string(ioc, str_val, sizeof(str_val)) < 0)
                return -1;
            break;
        case AMF_DATA_TYPE_OBJECT: {
            unsigned int keylen;

            while(url_ftell(ioc) < max_pos - 2 && (keylen = get_be16(ioc))) {
                url_fskip(ioc, keylen); //skip key string
                if(amf_parse_object(s, NULL, NULL, NULL, max_pos, depth + 1) < 0)
                    return -1; //if we couldn't skip, bomb out.
            }
            if(get_byte(ioc) != AMF_END_OF_OBJECT)
                return -1;
        }
            break;
        case AMF_DATA_TYPE_NULL:
        case AMF_DATA_TYPE_UNDEFINED:
        case AMF_DATA_TYPE_UNSUPPORTED:
            break; //these take up no additional space
        case AMF_DATA_TYPE_MIXEDARRAY:
            url_fskip(ioc, 4); //skip 32-bit max array index
            while(url_ftell(ioc) < max_pos - 2 && amf_get_string(ioc, str_val, sizeof(str_val)) > 0) {
                //this is the only case in which we would want a nested parse to not skip over the object
                if(amf_parse_object(s, astream, vstream, str_val, max_pos, depth + 1) < 0)
                    return -1;
            }
            if(get_byte(ioc) != AMF_END_OF_OBJECT)
                return -1;
            break;
        case AMF_DATA_TYPE_ARRAY: {
            unsigned int arraylen, i;

            arraylen = get_be32(ioc);
            for(i = 0; i < arraylen && url_ftell(ioc) < max_pos - 1; i++) {
                if(amf_parse_object(s, NULL, NULL, NULL, max_pos, depth + 1) < 0)
                    return -1; //if we couldn't skip, bomb out.
            }
        }
            break;
        case AMF_DATA_TYPE_DATE:
            url_fskip(ioc, 8 + 2); //timestamp (double) and UTC offset (int16)
            break;
        default: //unsupported type, we couldn't skip
            return -1;
    }

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

        if(amf_type == AMF_DATA_TYPE_BOOL) {
            if(!strcmp(key, "stereo") && acodec) acodec->channels = num_val > 0 ? 2 : 1;
        } else if(amf_type == AMF_DATA_TYPE_NUMBER) {
            if(!strcmp(key, "duration")) s->duration = num_val * AV_TIME_BASE;
//            else if(!strcmp(key, "width")  && vcodec && num_val > 0) vcodec->width  = num_val;
//            else if(!strcmp(key, "height") && vcodec && num_val > 0) vcodec->height = num_val;
            else if(!strcmp(key, "audiocodecid") && acodec && 0 <= (int)num_val)
                flv_set_audio_codec(s, astream, (int)num_val << FLV_AUDIO_CODECID_OFFSET);
            else if(!strcmp(key, "videocodecid") && vcodec && 0 <= (int)num_val)
                flv_set_video_codec(s, vstream, (int)num_val);
            else if(!strcmp(key, "audiosamplesize") && acodec && 0 < (int)num_val) {
                acodec->bits_per_coded_sample = num_val;
                //we may have to rewrite a previously read codecid because FLV only marks PCM endianness.
                if(num_val == 8 && (acodec->codec_id == CODEC_ID_PCM_S16BE || acodec->codec_id == CODEC_ID_PCM_S16LE))
                    acodec->codec_id = CODEC_ID_PCM_S8;
            }
            else if(!strcmp(key, "audiosamplerate") && acodec && num_val >= 0) {
                //some tools, like FLVTool2, write consistently approximate metadata sample rates
                if (!acodec->sample_rate) {
                    switch((int)num_val) {
                        case 44000: acodec->sample_rate = 44100  ; break;
                        case 22000: acodec->sample_rate = 22050  ; break;
                        case 11000: acodec->sample_rate = 11025  ; break;
                        case 5000 : acodec->sample_rate = 5512   ; break;
                        default   : acodec->sample_rate = num_val;
                    }
                }
            }
        }
    }

    return 0;
}

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

    astream = NULL;
    vstream = NULL;
    keylen = 0;
    ioc = s->pb;

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

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

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

    return 0;
}

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

static int flv_read_header(AVFormatContext *s,
                           AVFormatParameters *ap)
{
    int offset, flags;

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

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

    if(flags & FLV_HEADER_FLAG_HASVIDEO){
        if(!create_stream(s, 0))
            return AVERROR(ENOMEM);
    }
    if(flags & FLV_HEADER_FLAG_HASAUDIO){
        if(!create_stream(s, 1))
            return AVERROR(ENOMEM);
    }

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

    s->start_time = 0;

    return 0;
}

static int flv_get_extradata(AVFormatContext *s, AVStream *st, int size)
{
    av_free(st->codec->extradata);
    st->codec->extradata = av_mallocz(size + FF_INPUT_BUFFER_PADDING_SIZE);
    if (!st->codec->extradata)
        return AVERROR(ENOMEM);
    st->codec->extradata_size = size;
    get_buffer(s->pb, st->codec->extradata, st->codec->extradata_size);
    return 0;
}

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

 retry:
 for(;;){
    pos = url_ftell(s->pb);
    url_fskip(s->pb, 4); /* size of previous packet */
    type = get_byte(s->pb);
    size = get_be24(s->pb);
    dts = get_be24(s->pb);
    dts |= get_byte(s->pb) << 24;
//    av_log(s, AV_LOG_DEBUG, "type:%d, size:%d, dts:%d\n", type, size, dts);
    if (url_feof(s->pb))
        return AVERROR(EIO);
    url_fskip(s->pb, 3); /* stream id, always 0 */
    flags = 0;

    if(size == 0)
        continue;

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

    if (type == FLV_TAG_TYPE_AUDIO) {
        is_audio=1;
        flags = get_byte(s->pb);
        size--;
    } else if (type == FLV_TAG_TYPE_VIDEO) {
        is_audio=0;
        flags = get_byte(s->pb);
        size--;
        if ((flags & 0xf0) == 0x50) /* video info / command frame */
            goto skip;
    } else {
        if (type == FLV_TAG_TYPE_META && size > 13+1+4)
            flv_read_metabody(s, next);
        else /* skip packet */
            av_log(s, AV_LOG_ERROR, "skipping flv packet: type %d, size %d, flags %d\n", type, size, flags);
    skip:
        url_fseek(s->pb, next, SEEK_SET);
        continue;
    }

    /* skip empty data packets */
    if (!size)
        continue;

    /* now find stream */
    for(i=0;i<s->nb_streams;i++) {
        st = s->streams[i];
        if (st->id == is_audio)
            break;
    }
    if(i == s->nb_streams){
        av_log(NULL, AV_LOG_ERROR, "invalid stream\n");
        st= create_stream(s, is_audio);
        s->ctx_flags &= ~AVFMTCTX_NOHEADER;
    }
//    av_log(NULL, AV_LOG_DEBUG, "%d %X %d \n", is_audio, flags, st->discard);
    if(  (st->discard >= AVDISCARD_NONKEY && !((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY ||         is_audio))
       ||(st->discard >= AVDISCARD_BIDIR  &&  ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_DISP_INTER && !is_audio))
       || st->discard >= AVDISCARD_ALL
       ){
        url_fseek(s->pb, next, SEEK_SET);
        continue;
    }
    if ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY)
        av_add_index_entry(st, pos, dts, size, 0, AVINDEX_KEYFRAME);
    break;
 }

    // if not streamed and no duration from metadata then seek to end to find the duration from the timestamps
    if(!url_is_streamed(s->pb) && s->duration==AV_NOPTS_VALUE){
        int size;
        const int64_t pos= url_ftell(s->pb);
        const int64_t fsize= url_fsize(s->pb);
        url_fseek(s->pb, fsize-4, SEEK_SET);
        size= get_be32(s->pb);
        url_fseek(s->pb, fsize-3-size, SEEK_SET);
        if(size == get_be24(s->pb) + 11){
            s->duration= get_be24(s->pb) * (int64_t)AV_TIME_BASE / 1000;
        }
        url_fseek(s->pb, pos, SEEK_SET);
    }

    if(is_audio){
        if(!st->codec->channels || !st->codec->sample_rate || !st->codec->bits_per_coded_sample) {
            st->codec->channels = (flags & FLV_AUDIO_CHANNEL_MASK) == FLV_STEREO ? 2 : 1;
            st->codec->sample_rate = (44100 << ((flags & FLV_AUDIO_SAMPLERATE_MASK) >> FLV_AUDIO_SAMPLERATE_OFFSET) >> 3);
            st->codec->bits_per_coded_sample = (flags & FLV_AUDIO_SAMPLESIZE_MASK) ? 16 : 8;
        }
        if(!st->codec->codec_id){
            flv_set_audio_codec(s, st, flags & FLV_AUDIO_CODECID_MASK);
        }
    }else{
        size -= flv_set_video_codec(s, st, flags & FLV_VIDEO_CODECID_MASK);
    }

    if (st->codec->codec_id == CODEC_ID_AAC ||
        st->codec->codec_id == CODEC_ID_H264) {
        int type = get_byte(s->pb);
        size--;
        if (st->codec->codec_id == CODEC_ID_H264) {
            int32_t cts = (get_be24(s->pb)+0xff800000)^0xff800000; // sign extension
            pts = dts + cts;
            if (cts < 0) { // dts are wrong
                flv->wrong_dts = 1;
                av_log(s, AV_LOG_WARNING, "negative cts, previous timestamps might be wrong\n");
            }
            if (flv->wrong_dts)
                dts = AV_NOPTS_VALUE;
        }
        if (type == 0) {
            if ((ret = flv_get_extradata(s, st, size)) < 0)
                return ret;
            goto retry;
        }
    }

    ret= av_get_packet(s->pb, pkt, size);
    if (ret <= 0) {
        return AVERROR(EIO);
    }
    /* note: we need to modify the packet size here to handle the last
       packet */
    pkt->size = ret;
    pkt->dts = dts;
    pkt->pts = pts == AV_NOPTS_VALUE ? dts : pts;
    pkt->stream_index = st->index;

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

    return ret;
}

AVInputFormat flv_demuxer = {
    "flv",
    NULL_IF_CONFIG_SMALL("FLV format"),
    sizeof(FLVContext),
    flv_probe,
    flv_read_header,
    flv_read_packet,
    .extensions = "flv",
    .value = CODEC_ID_FLV1,
};