flvdec.c
Go to the documentation of this file.
1 /*
2  * FLV demuxer
3  * Copyright (c) 2003 The Libav 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 Libav.
11  *
12  * Libav 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  * Libav 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 Libav; if not, write to the Free Software
24  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
25  */
26 
27 #include "libavutil/avstring.h"
28 #include "libavutil/dict.h"
29 #include "libavutil/intfloat.h"
30 #include "libavutil/mathematics.h"
31 #include "libavcodec/bytestream.h"
32 #include "libavcodec/mpeg4audio.h"
33 #include "avformat.h"
34 #include "internal.h"
35 #include "avio_internal.h"
36 #include "flv.h"
37 
38 #define KEYFRAMES_TAG "keyframes"
39 #define KEYFRAMES_TIMESTAMP_TAG "times"
40 #define KEYFRAMES_BYTEOFFSET_TAG "filepositions"
41 
42 typedef struct {
43  int wrong_dts;
44  uint8_t *new_extradata[2];
45  int new_extradata_size[2];
48 } FLVContext;
49 
50 static int flv_probe(AVProbeData *p)
51 {
52  const uint8_t *d;
53 
54  d = p->buf;
55  if (d[0] == 'F' && d[1] == 'L' && d[2] == 'V' && d[3] < 5 && d[5]==0 && AV_RB32(d+5)>8) {
56  return AVPROBE_SCORE_MAX;
57  }
58  return 0;
59 }
60 
61 static void flv_set_audio_codec(AVFormatContext *s, AVStream *astream, AVCodecContext *acodec, int flv_codecid) {
62  switch(flv_codecid) {
63  //no distinction between S16 and S8 PCM codec flags
64  case FLV_CODECID_PCM:
65  acodec->codec_id = acodec->bits_per_coded_sample == 8 ? CODEC_ID_PCM_U8 :
66 #if HAVE_BIGENDIAN
68 #else
70 #endif
71  break;
72  case FLV_CODECID_PCM_LE:
73  acodec->codec_id = acodec->bits_per_coded_sample == 8 ? CODEC_ID_PCM_U8 : CODEC_ID_PCM_S16LE; break;
74  case FLV_CODECID_AAC : acodec->codec_id = CODEC_ID_AAC; break;
75  case FLV_CODECID_ADPCM: acodec->codec_id = CODEC_ID_ADPCM_SWF; break;
76  case FLV_CODECID_SPEEX:
77  acodec->codec_id = CODEC_ID_SPEEX;
78  acodec->sample_rate = 16000;
79  break;
80  case FLV_CODECID_MP3 : acodec->codec_id = CODEC_ID_MP3 ; astream->need_parsing = AVSTREAM_PARSE_FULL; break;
82  acodec->sample_rate = 8000; //in case metadata does not otherwise declare samplerate
83  acodec->codec_id = CODEC_ID_NELLYMOSER;
84  break;
86  acodec->sample_rate = 16000;
87  acodec->codec_id = CODEC_ID_NELLYMOSER;
88  break;
90  acodec->codec_id = CODEC_ID_NELLYMOSER;
91  break;
92  default:
93  av_log(s, AV_LOG_INFO, "Unsupported audio codec (%x)\n", flv_codecid >> FLV_AUDIO_CODECID_OFFSET);
94  acodec->codec_tag = flv_codecid >> FLV_AUDIO_CODECID_OFFSET;
95  }
96 }
97 
98 static int flv_set_video_codec(AVFormatContext *s, AVStream *vstream, int flv_codecid) {
99  AVCodecContext *vcodec = vstream->codec;
100  switch(flv_codecid) {
101  case FLV_CODECID_H263 : vcodec->codec_id = CODEC_ID_FLV1 ; break;
102  case FLV_CODECID_SCREEN: vcodec->codec_id = CODEC_ID_FLASHSV; break;
103  case FLV_CODECID_SCREEN2: vcodec->codec_id = CODEC_ID_FLASHSV2; break;
104  case FLV_CODECID_VP6 : vcodec->codec_id = CODEC_ID_VP6F ;
105  case FLV_CODECID_VP6A :
106  if(flv_codecid == FLV_CODECID_VP6A)
107  vcodec->codec_id = CODEC_ID_VP6A;
108  if(vcodec->extradata_size != 1) {
109  vcodec->extradata_size = 1;
110  vcodec->extradata = av_malloc(1);
111  }
112  vcodec->extradata[0] = avio_r8(s->pb);
113  return 1; // 1 byte body size adjustment for flv_read_packet()
114  case FLV_CODECID_H264:
115  vcodec->codec_id = CODEC_ID_H264;
116  return 3; // not 4, reading packet type will consume one byte
117  default:
118  av_log(s, AV_LOG_INFO, "Unsupported video codec (%x)\n", flv_codecid);
119  vcodec->codec_tag = flv_codecid;
120  }
121 
122  return 0;
123 }
124 
125 static int amf_get_string(AVIOContext *ioc, char *buffer, int buffsize) {
126  int length = avio_rb16(ioc);
127  if(length >= buffsize) {
128  avio_skip(ioc, length);
129  return -1;
130  }
131 
132  avio_read(ioc, buffer, length);
133 
134  buffer[length] = '\0';
135 
136  return length;
137 }
138 
139 static int parse_keyframes_index(AVFormatContext *s, AVIOContext *ioc, AVStream *vstream, int64_t max_pos) {
140  unsigned int arraylen = 0, timeslen = 0, fileposlen = 0, i;
141  double num_val;
142  char str_val[256];
143  int64_t *times = NULL;
144  int64_t *filepositions = NULL;
145  int ret = AVERROR(ENOSYS);
146  int64_t initial_pos = avio_tell(ioc);
147  AVDictionaryEntry *creator = av_dict_get(s->metadata, "metadatacreator",
148  NULL, 0);
149 
150  if (creator && !strcmp(creator->value, "MEGA")) {
151  /* Files with this metadatacreator tag seem to have filepositions
152  * pointing at the 4 trailer bytes of the previous packet,
153  * which isn't the norm (nor what we expect here, nor what
154  * jwplayer + lighttpd expect, nor what flvtool2 produces).
155  * Just ignore the index in this case, instead of risking trying
156  * to adjust it to something that might or might not work. */
157  return 0;
158  }
159 
160  while (avio_tell(ioc) < max_pos - 2 && amf_get_string(ioc, str_val, sizeof(str_val)) > 0) {
161  int64_t* current_array;
162 
163  // Expect array object in context
164  if (avio_r8(ioc) != AMF_DATA_TYPE_ARRAY)
165  break;
166 
167  arraylen = avio_rb32(ioc);
168  if (arraylen >> 28)
169  break;
170 
171  /*
172  * Expect only 'times' or 'filepositions' sub-arrays in other case refuse to use such metadata
173  * for indexing
174  */
175  if (!strcmp(KEYFRAMES_TIMESTAMP_TAG, str_val) && !times) {
176  if (!(times = av_mallocz(sizeof(*times) * arraylen))) {
177  ret = AVERROR(ENOMEM);
178  goto finish;
179  }
180  timeslen = arraylen;
181  current_array = times;
182  } else if (!strcmp(KEYFRAMES_BYTEOFFSET_TAG, str_val) && !filepositions) {
183  if (!(filepositions = av_mallocz(sizeof(*filepositions) * arraylen))) {
184  ret = AVERROR(ENOMEM);
185  goto finish;
186  }
187  fileposlen = arraylen;
188  current_array = filepositions;
189  } else // unexpected metatag inside keyframes, will not use such metadata for indexing
190  break;
191 
192  for (i = 0; i < arraylen && avio_tell(ioc) < max_pos - 1; i++) {
193  if (avio_r8(ioc) != AMF_DATA_TYPE_NUMBER)
194  goto finish;
195  num_val = av_int2double(avio_rb64(ioc));
196  current_array[i] = num_val;
197  }
198  if (times && filepositions) {
199  // All done, exiting at a position allowing amf_parse_object
200  // to finish parsing the object
201  ret = 0;
202  break;
203  }
204  }
205 
206  if (!ret && timeslen == fileposlen)
207  for (i = 0; i < fileposlen; i++)
208  av_add_index_entry(vstream, filepositions[i], times[i]*1000, 0, 0, AVINDEX_KEYFRAME);
209  else
210  av_log(s, AV_LOG_WARNING, "Invalid keyframes object, skipping.\n");
211 
212 finish:
213  av_freep(&times);
214  av_freep(&filepositions);
215  // If we got unexpected data, but successfully reset back to
216  // the start pos, the caller can continue parsing
217  if (ret < 0 && avio_seek(ioc, initial_pos, SEEK_SET) > 0)
218  return 0;
219  return ret;
220 }
221 
222 static int amf_parse_object(AVFormatContext *s, AVStream *astream, AVStream *vstream, const char *key, int64_t max_pos, int depth) {
223  AVCodecContext *acodec, *vcodec;
224  AVIOContext *ioc;
225  AMFDataType amf_type;
226  char str_val[256];
227  double num_val;
228 
229  num_val = 0;
230  ioc = s->pb;
231 
232  amf_type = avio_r8(ioc);
233 
234  switch(amf_type) {
236  num_val = av_int2double(avio_rb64(ioc)); break;
237  case AMF_DATA_TYPE_BOOL:
238  num_val = avio_r8(ioc); break;
240  if(amf_get_string(ioc, str_val, sizeof(str_val)) < 0)
241  return -1;
242  break;
243  case AMF_DATA_TYPE_OBJECT: {
244  unsigned int keylen;
245 
246  if ((vstream || astream) && key && !strcmp(KEYFRAMES_TAG, key) && depth == 1)
247  if (parse_keyframes_index(s, ioc, vstream ? vstream : astream,
248  max_pos) < 0)
249  return -1;
250 
251  while(avio_tell(ioc) < max_pos - 2 && (keylen = avio_rb16(ioc))) {
252  avio_skip(ioc, keylen); //skip key string
253  if(amf_parse_object(s, NULL, NULL, NULL, max_pos, depth + 1) < 0)
254  return -1; //if we couldn't skip, bomb out.
255  }
256  if(avio_r8(ioc) != AMF_END_OF_OBJECT)
257  return -1;
258  }
259  break;
260  case AMF_DATA_TYPE_NULL:
263  break; //these take up no additional space
265  avio_skip(ioc, 4); //skip 32-bit max array index
266  while(avio_tell(ioc) < max_pos - 2 && amf_get_string(ioc, str_val, sizeof(str_val)) > 0) {
267  //this is the only case in which we would want a nested parse to not skip over the object
268  if(amf_parse_object(s, astream, vstream, str_val, max_pos, depth + 1) < 0)
269  return -1;
270  }
271  if(avio_r8(ioc) != AMF_END_OF_OBJECT)
272  return -1;
273  break;
274  case AMF_DATA_TYPE_ARRAY: {
275  unsigned int arraylen, i;
276 
277  arraylen = avio_rb32(ioc);
278  for(i = 0; i < arraylen && avio_tell(ioc) < max_pos - 1; i++) {
279  if(amf_parse_object(s, NULL, NULL, NULL, max_pos, depth + 1) < 0)
280  return -1; //if we couldn't skip, bomb out.
281  }
282  }
283  break;
284  case AMF_DATA_TYPE_DATE:
285  avio_skip(ioc, 8 + 2); //timestamp (double) and UTC offset (int16)
286  break;
287  default: //unsupported type, we couldn't skip
288  return -1;
289  }
290 
291  if(depth == 1 && key) { //only look for metadata values when we are not nested and key != NULL
292  acodec = astream ? astream->codec : NULL;
293  vcodec = vstream ? vstream->codec : NULL;
294 
295  if (amf_type == AMF_DATA_TYPE_NUMBER) {
296  if (!strcmp(key, "duration"))
297  s->duration = num_val * AV_TIME_BASE;
298  else if (!strcmp(key, "videodatarate") && vcodec && 0 <= (int)(num_val * 1024.0))
299  vcodec->bit_rate = num_val * 1024.0;
300  else if (!strcmp(key, "audiodatarate") && acodec && 0 <= (int)(num_val * 1024.0))
301  acodec->bit_rate = num_val * 1024.0;
302  }
303 
304  if (!strcmp(key, "duration") ||
305  !strcmp(key, "filesize") ||
306  !strcmp(key, "width") ||
307  !strcmp(key, "height") ||
308  !strcmp(key, "videodatarate") ||
309  !strcmp(key, "framerate") ||
310  !strcmp(key, "videocodecid") ||
311  !strcmp(key, "audiodatarate") ||
312  !strcmp(key, "audiosamplerate") ||
313  !strcmp(key, "audiosamplesize") ||
314  !strcmp(key, "stereo") ||
315  !strcmp(key, "audiocodecid"))
316  return 0;
317 
318  if(amf_type == AMF_DATA_TYPE_BOOL) {
319  av_strlcpy(str_val, num_val > 0 ? "true" : "false", sizeof(str_val));
320  av_dict_set(&s->metadata, key, str_val, 0);
321  } else if(amf_type == AMF_DATA_TYPE_NUMBER) {
322  snprintf(str_val, sizeof(str_val), "%.f", num_val);
323  av_dict_set(&s->metadata, key, str_val, 0);
324  } else if (amf_type == AMF_DATA_TYPE_STRING)
325  av_dict_set(&s->metadata, key, str_val, 0);
326  }
327 
328  return 0;
329 }
330 
331 static int flv_read_metabody(AVFormatContext *s, int64_t next_pos) {
332  AMFDataType type;
333  AVStream *stream, *astream, *vstream;
334  AVIOContext *ioc;
335  int i;
336  char buffer[11]; //only needs to hold the string "onMetaData". Anything longer is something we don't want.
337 
338  astream = NULL;
339  vstream = NULL;
340  ioc = s->pb;
341 
342  //first object needs to be "onMetaData" string
343  type = avio_r8(ioc);
344  if(type != AMF_DATA_TYPE_STRING || amf_get_string(ioc, buffer, sizeof(buffer)) < 0 || strcmp(buffer, "onMetaData"))
345  return -1;
346 
347  //find the streams now so that amf_parse_object doesn't need to do the lookup every time it is called.
348  for(i = 0; i < s->nb_streams; i++) {
349  stream = s->streams[i];
350  if (stream->codec->codec_type == AVMEDIA_TYPE_AUDIO) astream = stream;
351  else if(stream->codec->codec_type == AVMEDIA_TYPE_VIDEO) vstream = stream;
352  }
353 
354  //parse the second object (we want a mixed array)
355  if(amf_parse_object(s, astream, vstream, buffer, next_pos, 0) < 0)
356  return -1;
357 
358  return 0;
359 }
360 
361 static AVStream *create_stream(AVFormatContext *s, int is_audio){
363  if (!st)
364  return NULL;
365  st->id = is_audio;
367  avpriv_set_pts_info(st, 32, 1, 1000); /* 32 bit pts in ms */
368  return st;
369 }
370 
372  AVFormatParameters *ap)
373 {
374  int offset, flags;
375 
376  avio_skip(s->pb, 4);
377  flags = avio_r8(s->pb);
378  /* old flvtool cleared this field */
379  /* FIXME: better fix needed */
380  if (!flags) {
382  av_log(s, AV_LOG_WARNING, "Broken FLV file, which says no streams present, this might fail\n");
383  }
384 
388 
389  if(flags & FLV_HEADER_FLAG_HASVIDEO){
390  if(!create_stream(s, 0))
391  return AVERROR(ENOMEM);
392  }
393  if(flags & FLV_HEADER_FLAG_HASAUDIO){
394  if(!create_stream(s, 1))
395  return AVERROR(ENOMEM);
396  }
397 
398  offset = avio_rb32(s->pb);
399  avio_seek(s->pb, offset, SEEK_SET);
400  avio_skip(s->pb, 4);
401 
402  s->start_time = 0;
403 
404  return 0;
405 }
406 
408 {
409  FLVContext *flv = s->priv_data;
410  av_freep(&flv->new_extradata[0]);
411  av_freep(&flv->new_extradata[1]);
412  return 0;
413 }
414 
416 {
417  av_free(st->codec->extradata);
419  if (!st->codec->extradata)
420  return AVERROR(ENOMEM);
421  st->codec->extradata_size = size;
423  return 0;
424 }
425 
426 static int flv_queue_extradata(FLVContext *flv, AVIOContext *pb, int stream,
427  int size)
428 {
429  av_free(flv->new_extradata[stream]);
431  if (!flv->new_extradata[stream])
432  return AVERROR(ENOMEM);
433  flv->new_extradata_size[stream] = size;
434  avio_read(pb, flv->new_extradata[stream], size);
435  return 0;
436 }
437 
439 {
440  FLVContext *flv = s->priv_data;
441  int ret, i, type, size, flags, is_audio;
442  int64_t next, pos;
443  int64_t dts, pts = AV_NOPTS_VALUE;
444  int sample_rate = 0, channels = 0;
445  AVStream *st = NULL;
446 
447  for(;;avio_skip(s->pb, 4)){ /* pkt size is repeated at end. skip it */
448  pos = avio_tell(s->pb);
449  type = avio_r8(s->pb);
450  size = avio_rb24(s->pb);
451  dts = avio_rb24(s->pb);
452  dts |= avio_r8(s->pb) << 24;
453  av_dlog(s, "type:%d, size:%d, dts:%"PRId64"\n", type, size, dts);
454  if (s->pb->eof_reached)
455  return AVERROR_EOF;
456  avio_skip(s->pb, 3); /* stream id, always 0 */
457  flags = 0;
458 
459  if(size == 0)
460  continue;
461 
462  next= size + avio_tell(s->pb);
463 
464  if (type == FLV_TAG_TYPE_AUDIO) {
465  is_audio=1;
466  flags = avio_r8(s->pb);
467  size--;
468  } else if (type == FLV_TAG_TYPE_VIDEO) {
469  is_audio=0;
470  flags = avio_r8(s->pb);
471  size--;
472  if ((flags & 0xf0) == 0x50) /* video info / command frame */
473  goto skip;
474  } else {
475  if (type == FLV_TAG_TYPE_META && size > 13+1+4)
476  flv_read_metabody(s, next);
477  else /* skip packet */
478  av_log(s, AV_LOG_DEBUG, "skipping flv packet: type %d, size %d, flags %d\n", type, size, flags);
479  skip:
480  avio_seek(s->pb, next, SEEK_SET);
481  continue;
482  }
483 
484  /* skip empty data packets */
485  if (!size)
486  continue;
487 
488  /* now find stream */
489  for(i=0;i<s->nb_streams;i++) {
490  st = s->streams[i];
491  if (st->id == is_audio)
492  break;
493  }
494  if(i == s->nb_streams){
495  av_log(s, AV_LOG_ERROR, "invalid stream\n");
496  st= create_stream(s, is_audio);
498  }
499  av_dlog(s, "%d %X %d \n", is_audio, flags, st->discard);
500  if( (st->discard >= AVDISCARD_NONKEY && !((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY || is_audio))
501  ||(st->discard >= AVDISCARD_BIDIR && ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_DISP_INTER && !is_audio))
502  || st->discard >= AVDISCARD_ALL
503  ){
504  avio_seek(s->pb, next, SEEK_SET);
505  continue;
506  }
507  if ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY)
508  av_add_index_entry(st, pos, dts, size, 0, AVINDEX_KEYFRAME);
509  break;
510  }
511 
512  // if not streamed and no duration from metadata then seek to end to find the duration from the timestamps
513  if(s->pb->seekable && (!s->duration || s->duration==AV_NOPTS_VALUE)){
514  int size;
515  const int64_t pos= avio_tell(s->pb);
516  const int64_t fsize= avio_size(s->pb);
517  avio_seek(s->pb, fsize-4, SEEK_SET);
518  size= avio_rb32(s->pb);
519  avio_seek(s->pb, fsize-3-size, SEEK_SET);
520  if(size == avio_rb24(s->pb) + 11){
521  uint32_t ts = avio_rb24(s->pb);
522  ts |= avio_r8(s->pb) << 24;
523  s->duration = ts * (int64_t)AV_TIME_BASE / 1000;
524  }
525  avio_seek(s->pb, pos, SEEK_SET);
526  }
527 
528  if(is_audio){
529  int bits_per_coded_sample;
530  channels = (flags & FLV_AUDIO_CHANNEL_MASK) == FLV_STEREO ? 2 : 1;
531  sample_rate = (44100 << ((flags & FLV_AUDIO_SAMPLERATE_MASK) >> FLV_AUDIO_SAMPLERATE_OFFSET) >> 3);
532  bits_per_coded_sample = (flags & FLV_AUDIO_SAMPLESIZE_MASK) ? 16 : 8;
533  if(!st->codec->channels || !st->codec->sample_rate || !st->codec->bits_per_coded_sample) {
534  st->codec->channels = channels;
535  st->codec->sample_rate = sample_rate;
536  st->codec->bits_per_coded_sample = bits_per_coded_sample;
537  }
538  if(!st->codec->codec_id){
539  flv_set_audio_codec(s, st, st->codec, flags & FLV_AUDIO_CODECID_MASK);
540  flv->last_sample_rate = st->codec->sample_rate;
541  flv->last_channels = st->codec->channels;
542  } else {
543  AVCodecContext ctx;
544  ctx.sample_rate = sample_rate;
545  flv_set_audio_codec(s, st, &ctx, flags & FLV_AUDIO_CODECID_MASK);
546  sample_rate = ctx.sample_rate;
547  }
548  }else{
549  size -= flv_set_video_codec(s, st, flags & FLV_VIDEO_CODECID_MASK);
550  }
551 
552  if (st->codec->codec_id == CODEC_ID_AAC ||
553  st->codec->codec_id == CODEC_ID_H264) {
554  int type = avio_r8(s->pb);
555  size--;
556  if (st->codec->codec_id == CODEC_ID_H264) {
557  int32_t cts = (avio_rb24(s->pb)+0xff800000)^0xff800000; // sign extension
558  pts = dts + cts;
559  if (cts < 0) { // dts are wrong
560  flv->wrong_dts = 1;
561  av_log(s, AV_LOG_WARNING, "negative cts, previous timestamps might be wrong\n");
562  }
563  if (flv->wrong_dts)
564  dts = AV_NOPTS_VALUE;
565  }
566  if (type == 0) {
567  if (st->codec->extradata) {
568  if ((ret = flv_queue_extradata(flv, s->pb, is_audio, size)) < 0)
569  return ret;
570  ret = AVERROR(EAGAIN);
571  goto leave;
572  }
573  if ((ret = flv_get_extradata(s, st, size)) < 0)
574  return ret;
575  if (st->codec->codec_id == CODEC_ID_AAC) {
576  MPEG4AudioConfig cfg;
578  st->codec->extradata_size * 8, 1);
579  st->codec->channels = cfg.channels;
580  if (cfg.ext_sample_rate)
581  st->codec->sample_rate = cfg.ext_sample_rate;
582  else
583  st->codec->sample_rate = cfg.sample_rate;
584  av_dlog(s, "mp4a config channels %d sample rate %d\n",
585  st->codec->channels, st->codec->sample_rate);
586  }
587 
588  ret = AVERROR(EAGAIN);
589  goto leave;
590  }
591  }
592 
593  /* skip empty data packets */
594  if (!size) {
595  ret = AVERROR(EAGAIN);
596  goto leave;
597  }
598 
599  ret= av_get_packet(s->pb, pkt, size);
600  if (ret < 0) {
601  return AVERROR(EIO);
602  }
603  /* note: we need to modify the packet size here to handle the last
604  packet */
605  pkt->size = ret;
606  pkt->dts = dts;
607  pkt->pts = pts == AV_NOPTS_VALUE ? dts : pts;
608  pkt->stream_index = st->index;
609  if (flv->new_extradata[is_audio]) {
611  flv->new_extradata_size[is_audio]);
612  if (side) {
613  memcpy(side, flv->new_extradata[is_audio],
614  flv->new_extradata_size[is_audio]);
615  av_freep(&flv->new_extradata[is_audio]);
616  flv->new_extradata_size[is_audio] = 0;
617  }
618  }
619  if (is_audio && (sample_rate != flv->last_sample_rate ||
620  channels != flv->last_channels)) {
621  flv->last_sample_rate = sample_rate;
622  flv->last_channels = channels;
623  ff_add_param_change(pkt, channels, 0, sample_rate, 0, 0);
624  }
625 
626  if (is_audio || ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY))
627  pkt->flags |= AV_PKT_FLAG_KEY;
628 
629 leave:
630  avio_skip(s->pb, 4);
631  return ret;
632 }
633 
634 static int flv_read_seek(AVFormatContext *s, int stream_index,
635  int64_t ts, int flags)
636 {
637  return avio_seek_time(s->pb, stream_index, ts, flags);
638 }
639 
640 #if 0 /* don't know enough to implement this */
641 static int flv_read_seek2(AVFormatContext *s, int stream_index,
642  int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
643 {
644  int ret = AVERROR(ENOSYS);
645 
646  if (ts - min_ts > (uint64_t)(max_ts - ts)) flags |= AVSEEK_FLAG_BACKWARD;
647 
648  if (!s->pb->seekable) {
649  if (stream_index < 0) {
650  stream_index = av_find_default_stream_index(s);
651  if (stream_index < 0)
652  return -1;
653 
654  /* timestamp for default must be expressed in AV_TIME_BASE units */
655  ts = av_rescale_rnd(ts, 1000, AV_TIME_BASE,
657  }
658  ret = avio_seek_time(s->pb, stream_index, ts, flags);
659  }
660 
661  if (ret == AVERROR(ENOSYS))
662  ret = av_seek_frame(s, stream_index, ts, flags);
663  return ret;
664 }
665 #endif
666 
668  .name = "flv",
669  .long_name = NULL_IF_CONFIG_SMALL("FLV format"),
670  .priv_data_size = sizeof(FLVContext),
675 #if 0
676  .read_seek2 = flv_read_seek2,
677 #endif
679  .extensions = "flv",
680  .value = CODEC_ID_FLV1,
681 };