libavformat/flvdec.c

   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
  27 #include "libavutil/avstring.h"
  28 #include "libavcodec/bytestream.h"
  29 #include "libavcodec/mpeg4audio.h"
  30 #include "avformat.h"
  31 #include "flv.h"
  32
  33 typedef struct {
  34     int wrong_dts; ///< wrong dts due to negative cts
  35 } FLVContext;
  36
  37 static int flv_probe(AVProbeData *p)
  38 {
  39     const uint8_t *d;
  40
  41     d = p->buf;
  42     if (d[0] == 'F' && d[1] == 'L' && d[2] == 'V' && d[3] < 5 && d[5]==0) {
  43         return AVPROBE_SCORE_MAX;
  44     }
  45     return 0;
  46 }
  47
  48 /**
  49  * Builds a Speex header.
  50  * This is not needed for the libavcodec libspeex decoder, but is needed for
  51  * stream copy and for decoders which require a header.
  52  */
  53 static void flv_build_speex_header(uint8_t *extradata)
  54 {
  55     memset(extradata, 0, 80);
  56     bytestream_put_buffer(&extradata, "Speex   ", 8);   // speex_string
  57     bytestream_put_buffer(&extradata, "1.2rc1",   6);   // speex_version
  58     extradata += 14;                                    // speex_version padding
  59     bytestream_put_le32(&extradata,     1);             // speex_version_id
  60     bytestream_put_le32(&extradata,    80);             // header_size
  61     bytestream_put_le32(&extradata, 16000);             // rate
  62     bytestream_put_le32(&extradata,     1);             // mode
  63     bytestream_put_le32(&extradata,     4);             // mode_bitstream_version
  64     bytestream_put_le32(&extradata,     1);             // nb_channels
  65     bytestream_put_le32(&extradata,    -1);             // bitrate
  66     bytestream_put_le32(&extradata,   320);             // frame_size
  67                                                         // vbr = 0
  68                                                         // frames_per_packet = 0
  69                                                         // extra_headers = 0
  70                                                         // reserved1 = 0
  71                                                         // reserved2 = 0
  72 }
  73
  74 static void flv_set_audio_codec(AVFormatContext *s, AVStream *astream, int flv_codecid) {
  75     AVCodecContext *acodec = astream->codec;
  76     switch(flv_codecid) {
  77         //no distinction between S16 and S8 PCM codec flags
  78         case FLV_CODECID_PCM:
  79             acodec->codec_id = acodec->bits_per_coded_sample == 8 ? CODEC_ID_PCM_S8 :
  80 #if HAVE_BIGENDIAN
  81                                 CODEC_ID_PCM_S16BE;
  82 #else
  83                                 CODEC_ID_PCM_S16LE;
  84 #endif
  85             break;
  86         case FLV_CODECID_PCM_LE:
  87             acodec->codec_id = acodec->bits_per_coded_sample == 8 ? CODEC_ID_PCM_S8 : CODEC_ID_PCM_S16LE; break;
  88         case FLV_CODECID_AAC  : acodec->codec_id = CODEC_ID_AAC;                                    break;
  89         case FLV_CODECID_ADPCM: acodec->codec_id = CODEC_ID_ADPCM_SWF;                              break;
  90         case FLV_CODECID_SPEEX:
  91             acodec->codec_id = CODEC_ID_SPEEX;
  92             acodec->sample_rate = 16000;
  93             acodec->extradata = av_mallocz(80 + FF_INPUT_BUFFER_PADDING_SIZE);
  94             if (acodec->extradata) {
  95                 acodec->extradata_size = 80;
  96                 flv_build_speex_header(acodec->extradata);
  97             } else {
  98                 av_log(s, AV_LOG_WARNING, "Unable to create Speex extradata\n");
  99             }
 100             break;
 101         case FLV_CODECID_MP3  : acodec->codec_id = CODEC_ID_MP3      ; astream->need_parsing = AVSTREAM_PARSE_FULL; break;
 102         case FLV_CODECID_NELLYMOSER_8KHZ_MONO:
 103             acodec->sample_rate = 8000; //in case metadata does not otherwise declare samplerate
 104         case FLV_CODECID_NELLYMOSER:
 105             acodec->codec_id = CODEC_ID_NELLYMOSER;
 106             break;
 107         default:
 108             av_log(s, AV_LOG_INFO, "Unsupported audio codec (%x)\n", flv_codecid >> FLV_AUDIO_CODECID_OFFSET);
 109             acodec->codec_tag = flv_codecid >> FLV_AUDIO_CODECID_OFFSET;
 110     }
 111 }
 112
 113 static int flv_set_video_codec(AVFormatContext *s, AVStream *vstream, int flv_codecid) {
 114     AVCodecContext *vcodec = vstream->codec;
 115     switch(flv_codecid) {
 116         case FLV_CODECID_H263  : vcodec->codec_id = CODEC_ID_FLV1   ; break;
 117         case FLV_CODECID_SCREEN: vcodec->codec_id = CODEC_ID_FLASHSV; break;
 118         case FLV_CODECID_VP6   : vcodec->codec_id = CODEC_ID_VP6F   ;
 119         case FLV_CODECID_VP6A  :
 120             if(flv_codecid == FLV_CODECID_VP6A)
 121                 vcodec->codec_id = CODEC_ID_VP6A;
 122             if(vcodec->extradata_size != 1) {
 123                 vcodec->extradata_size = 1;
 124                 vcodec->extradata = av_malloc(1);
 125             }
 126             vcodec->extradata[0] = get_byte(s->pb);
 127             return 1; // 1 byte body size adjustment for flv_read_packet()
 128         case FLV_CODECID_H264:
 129             vcodec->codec_id = CODEC_ID_H264;
 130             return 3; // not 4, reading packet type will consume one byte
 131         default:
 132             av_log(s, AV_LOG_INFO, "Unsupported video codec (%x)\n", flv_codecid);
 133             vcodec->codec_tag = flv_codecid;
 134     }
 135
 136     return 0;
 137 }
 138
 139 static int amf_get_string(ByteIOContext *ioc, char *buffer, int buffsize) {
 140     int length = get_be16(ioc);
 141     if(length >= buffsize) {
 142         url_fskip(ioc, length);
 143         return -1;
 144     }
 145
 146     get_buffer(ioc, buffer, length);
 147
 148     buffer[length] = '\0';
 149
 150     return length;
 151 }
 152
 153 static int amf_parse_object(AVFormatContext *s, AVStream *astream, AVStream *vstream, const char *key, int64_t max_pos, int depth) {
 154     AVCodecContext *acodec, *vcodec;
 155     ByteIOContext *ioc;
 156     AMFDataType amf_type;
 157     char str_val[256];
 158     double num_val;
 159
 160     num_val = 0;
 161     ioc = s->pb;
 162
 163     amf_type = get_byte(ioc);
 164
 165     switch(amf_type) {
 166         case AMF_DATA_TYPE_NUMBER:
 167             num_val = av_int2dbl(get_be64(ioc)); break;
 168         case AMF_DATA_TYPE_BOOL:
 169             num_val = get_byte(ioc); break;
 170         case AMF_DATA_TYPE_STRING:
 171             if(amf_get_string(ioc, str_val, sizeof(str_val)) < 0)
 172                 return -1;
 173             break;
 174         case AMF_DATA_TYPE_OBJECT: {
 175             unsigned int keylen;
 176
 177             while(url_ftell(ioc) < max_pos - 2 && (keylen = get_be16(ioc))) {
 178                 url_fskip(ioc, keylen); //skip key string
 179                 if(amf_parse_object(s, NULL, NULL, NULL, max_pos, depth + 1) < 0)
 180                     return -1; //if we couldn't skip, bomb out.
 181             }
 182             if(get_byte(ioc) != AMF_END_OF_OBJECT)
 183                 return -1;
 184         }
 185             break;
 186         case AMF_DATA_TYPE_NULL:
 187         case AMF_DATA_TYPE_UNDEFINED:
 188         case AMF_DATA_TYPE_UNSUPPORTED:
 189             break; //these take up no additional space
 190         case AMF_DATA_TYPE_MIXEDARRAY:
 191             url_fskip(ioc, 4); //skip 32-bit max array index
 192             while(url_ftell(ioc) < max_pos - 2 && amf_get_string(ioc, str_val, sizeof(str_val)) > 0) {
 193                 //this is the only case in which we would want a nested parse to not skip over the object
 194                 if(amf_parse_object(s, astream, vstream, str_val, max_pos, depth + 1) < 0)
 195                     return -1;
 196             }
 197             if(get_byte(ioc) != AMF_END_OF_OBJECT)
 198                 return -1;
 199             break;
 200         case AMF_DATA_TYPE_ARRAY: {
 201             unsigned int arraylen, i;
 202
 203             arraylen = get_be32(ioc);
 204             for(i = 0; i < arraylen && url_ftell(ioc) < max_pos - 1; i++) {
 205                 if(amf_parse_object(s, NULL, NULL, NULL, max_pos, depth + 1) < 0)
 206                     return -1; //if we couldn't skip, bomb out.
 207             }
 208         }
 209             break;
 210         case AMF_DATA_TYPE_DATE:
 211             url_fskip(ioc, 8 + 2); //timestamp (double) and UTC offset (int16)
 212             break;
 213         default: //unsupported type, we couldn't skip
 214             return -1;
 215     }
 216
 217     if(depth == 1 && key) { //only look for metadata values when we are not nested and key != NULL
 218         acodec = astream ? astream->codec : NULL;
 219         vcodec = vstream ? vstream->codec : NULL;
 220
 221         if(amf_type == AMF_DATA_TYPE_BOOL) {
 222             av_strlcpy(str_val, num_val > 0 ? "true" : "false", sizeof(str_val));
 223             av_metadata_set(&s->metadata, key, str_val);
 224         } else if(amf_type == AMF_DATA_TYPE_NUMBER) {
 225             snprintf(str_val, sizeof(str_val), "%.f", num_val);
 226             av_metadata_set(&s->metadata, key, str_val);
 227             if(!strcmp(key, "duration")) s->duration = num_val * AV_TIME_BASE;
 228             else if(!strcmp(key, "videodatarate") && vcodec && 0 <= (int)(num_val * 1024.0))
 229                 vcodec->bit_rate = num_val * 1024.0;
 230         } else if (amf_type == AMF_DATA_TYPE_STRING)
 231           av_metadata_set(&s->metadata, key, str_val);
 232     }
 233
 234     return 0;
 235 }
 236
 237 static int flv_read_metabody(AVFormatContext *s, int64_t next_pos) {
 238     AMFDataType type;
 239     AVStream *stream, *astream, *vstream;
 240     ByteIOContext *ioc;
 241     int i;
 242     char buffer[11]; //only needs to hold the string "onMetaData". Anything longer is something we don't want.
 243
 244     astream = NULL;
 245     vstream = NULL;
 246     ioc = s->pb;
 247
 248     //first object needs to be "onMetaData" string
 249     type = get_byte(ioc);
 250     if(type != AMF_DATA_TYPE_STRING || amf_get_string(ioc, buffer, sizeof(buffer)) < 0 || strcmp(buffer, "onMetaData"))
 251         return -1;
 252
 253     //find the streams now so that amf_parse_object doesn't need to do the lookup every time it is called.
 254     for(i = 0; i < s->nb_streams; i++) {
 255         stream = s->streams[i];
 256         if     (stream->codec->codec_type == CODEC_TYPE_AUDIO) astream = stream;
 257         else if(stream->codec->codec_type == CODEC_TYPE_VIDEO) vstream = stream;
 258     }
 259
 260     //parse the second object (we want a mixed array)
 261     if(amf_parse_object(s, astream, vstream, buffer, next_pos, 0) < 0)
 262         return -1;
 263
 264     return 0;
 265 }
 266
 267 static AVStream *create_stream(AVFormatContext *s, int is_audio){
 268     AVStream *st = av_new_stream(s, is_audio);
 269     if (!st)
 270         return NULL;
 271     st->codec->codec_type = is_audio ? CODEC_TYPE_AUDIO : CODEC_TYPE_VIDEO;
 272     av_set_pts_info(st, 32, 1, 1000); /* 32 bit pts in ms */
 273     return st;
 274 }
 275
 276 static int flv_read_header(AVFormatContext *s,
 277                            AVFormatParameters *ap)
 278 {
 279     int offset, flags;
 280
 281     url_fskip(s->pb, 4);
 282     flags = get_byte(s->pb);
 283     /* old flvtool cleared this field */
 284     /* FIXME: better fix needed */
 285     if (!flags) {
 286         flags = FLV_HEADER_FLAG_HASVIDEO | FLV_HEADER_FLAG_HASAUDIO;
 287         av_log(s, AV_LOG_WARNING, "Broken FLV file, which says no streams present, this might fail\n");
 288     }
 289
 290     if((flags & (FLV_HEADER_FLAG_HASVIDEO|FLV_HEADER_FLAG_HASAUDIO))
 291              != (FLV_HEADER_FLAG_HASVIDEO|FLV_HEADER_FLAG_HASAUDIO))
 292         s->ctx_flags |= AVFMTCTX_NOHEADER;
 293
 294     if(flags & FLV_HEADER_FLAG_HASVIDEO){
 295         if(!create_stream(s, 0))
 296             return AVERROR(ENOMEM);
 297     }
 298     if(flags & FLV_HEADER_FLAG_HASAUDIO){
 299         if(!create_stream(s, 1))
 300             return AVERROR(ENOMEM);
 301     }
 302
 303     offset = get_be32(s->pb);
 304     url_fseek(s->pb, offset, SEEK_SET);
 305
 306     s->start_time = 0;
 307
 308     return 0;
 309 }
 310
 311 static int flv_get_extradata(AVFormatContext *s, AVStream *st, int size)
 312 {
 313     av_free(st->codec->extradata);
 314     st->codec->extradata = av_mallocz(size + FF_INPUT_BUFFER_PADDING_SIZE);
 315     if (!st->codec->extradata)
 316         return AVERROR(ENOMEM);
 317     st->codec->extradata_size = size;
 318     get_buffer(s->pb, st->codec->extradata, st->codec->extradata_size);
 319     return 0;
 320 }
 321
 322 static int flv_read_packet(AVFormatContext *s, AVPacket *pkt)
 323 {
 324     FLVContext *flv = s->priv_data;
 325     int ret, i, type, size, flags, is_audio;
 326     int64_t next, pos;
 327     int64_t dts, pts = AV_NOPTS_VALUE;
 328     AVStream *st = NULL;
 329
 330  for(;;){
 331     pos = url_ftell(s->pb);
 332     url_fskip(s->pb, 4); /* size of previous packet */
 333     type = get_byte(s->pb);
 334     size = get_be24(s->pb);
 335     dts = get_be24(s->pb);
 336     dts |= get_byte(s->pb) << 24;
 337 //    av_log(s, AV_LOG_DEBUG, "type:%d, size:%d, dts:%d\n", type, size, dts);
 338     if (url_feof(s->pb))
 339         return AVERROR_EOF;
 340     url_fskip(s->pb, 3); /* stream id, always 0 */
 341     flags = 0;
 342
 343     if(size == 0)
 344         continue;
 345
 346     next= size + url_ftell(s->pb);
 347
 348     if (type == FLV_TAG_TYPE_AUDIO) {
 349         is_audio=1;
 350         flags = get_byte(s->pb);
 351         size--;
 352     } else if (type == FLV_TAG_TYPE_VIDEO) {
 353         is_audio=0;
 354         flags = get_byte(s->pb);
 355         size--;
 356         if ((flags & 0xf0) == 0x50) /* video info / command frame */
 357             goto skip;
 358     } else {
 359         if (type == FLV_TAG_TYPE_META && size > 13+1+4)
 360             flv_read_metabody(s, next);
 361         else /* skip packet */
 362             av_log(s, AV_LOG_DEBUG, "skipping flv packet: type %d, size %d, flags %d\n", type, size, flags);
 363     skip:
 364         url_fseek(s->pb, next, SEEK_SET);
 365         continue;
 366     }
 367
 368     /* skip empty data packets */
 369     if (!size)
 370         continue;
 371
 372     /* now find stream */
 373     for(i=0;i<s->nb_streams;i++) {
 374         st = s->streams[i];
 375         if (st->id == is_audio)
 376             break;
 377     }
 378     if(i == s->nb_streams){
 379         av_log(s, AV_LOG_ERROR, "invalid stream\n");
 380         st= create_stream(s, is_audio);
 381         s->ctx_flags &= ~AVFMTCTX_NOHEADER;
 382     }
 383 //    av_log(s, AV_LOG_DEBUG, "%d %X %d \n", is_audio, flags, st->discard);
 384     if(  (st->discard >= AVDISCARD_NONKEY && !((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY ||         is_audio))
 385        ||(st->discard >= AVDISCARD_BIDIR  &&  ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_DISP_INTER && !is_audio))
 386        || st->discard >= AVDISCARD_ALL
 387        ){
 388         url_fseek(s->pb, next, SEEK_SET);
 389         continue;
 390     }
 391     if ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY)
 392         av_add_index_entry(st, pos, dts, size, 0, AVINDEX_KEYFRAME);
 393     break;
 394  }
 395
 396     // if not streamed and no duration from metadata then seek to end to find the duration from the timestamps
 397     if(!url_is_streamed(s->pb) && s->duration==AV_NOPTS_VALUE){
 398         int size;
 399         const int64_t pos= url_ftell(s->pb);
 400         const int64_t fsize= url_fsize(s->pb);
 401         url_fseek(s->pb, fsize-4, SEEK_SET);
 402         size= get_be32(s->pb);
 403         url_fseek(s->pb, fsize-3-size, SEEK_SET);
 404         if(size == get_be24(s->pb) + 11){
 405             s->duration= get_be24(s->pb) * (int64_t)AV_TIME_BASE / 1000;
 406         }
 407         url_fseek(s->pb, pos, SEEK_SET);
 408     }
 409
 410     if(is_audio){
 411         if(!st->codec->channels || !st->codec->sample_rate || !st->codec->bits_per_coded_sample) {
 412             st->codec->channels = (flags & FLV_AUDIO_CHANNEL_MASK) == FLV_STEREO ? 2 : 1;
 413             st->codec->sample_rate = (44100 << ((flags & FLV_AUDIO_SAMPLERATE_MASK) >> FLV_AUDIO_SAMPLERATE_OFFSET) >> 3);
 414             st->codec->bits_per_coded_sample = (flags & FLV_AUDIO_SAMPLESIZE_MASK) ? 16 : 8;
 415         }
 416         if(!st->codec->codec_id){
 417             flv_set_audio_codec(s, st, flags & FLV_AUDIO_CODECID_MASK);
 418         }
 419     }else{
 420         size -= flv_set_video_codec(s, st, flags & FLV_VIDEO_CODECID_MASK);
 421     }
 422
 423     if (st->codec->codec_id == CODEC_ID_AAC ||
 424         st->codec->codec_id == CODEC_ID_H264) {
 425         int type = get_byte(s->pb);
 426         size--;
 427         if (st->codec->codec_id == CODEC_ID_H264) {
 428             int32_t cts = (get_be24(s->pb)+0xff800000)^0xff800000; // sign extension
 429             pts = dts + cts;
 430             if (cts < 0) { // dts are wrong
 431                 flv->wrong_dts = 1;
 432                 av_log(s, AV_LOG_WARNING, "negative cts, previous timestamps might be wrong\n");
 433             }
 434             if (flv->wrong_dts)
 435                 dts = AV_NOPTS_VALUE;
 436         }
 437         if (type == 0) {
 438             if ((ret = flv_get_extradata(s, st, size)) < 0)
 439                 return ret;
 440             if (st->codec->codec_id == CODEC_ID_AAC) {
 441                 MPEG4AudioConfig cfg;
 442                 ff_mpeg4audio_get_config(&cfg, st->codec->extradata,
 443                                          st->codec->extradata_size);
 444                 if (cfg.chan_config > 7)
 445                     return -1;
 446                 st->codec->channels = ff_mpeg4audio_channels[cfg.chan_config];
 447                 st->codec->sample_rate = cfg.sample_rate;
 448                 dprintf(s, "mp4a config channels %d sample rate %d\n",
 449                         st->codec->channels, st->codec->sample_rate);
 450             }
 451
 452             return AVERROR(EAGAIN);
 453         }
 454     }
 455
 456     /* skip empty data packets */
 457     if (!size)
 458         return AVERROR(EAGAIN);
 459
 460     ret= av_get_packet(s->pb, pkt, size);
 461     if (ret < 0) {
 462         return AVERROR(EIO);
 463     }
 464     /* note: we need to modify the packet size here to handle the last
 465        packet */
 466     pkt->size = ret;
 467     pkt->dts = dts;
 468     pkt->pts = pts == AV_NOPTS_VALUE ? dts : pts;
 469     pkt->stream_index = st->index;
 470
 471     if (is_audio || ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY))
 472         pkt->flags |= PKT_FLAG_KEY;
 473
 474     return ret;
 475 }
 476
 477 AVInputFormat flv_demuxer = {
 478     "flv",
 479     NULL_IF_CONFIG_SMALL("FLV format"),
 480     sizeof(FLVContext),
 481     flv_probe,
 482     flv_read_header,
 483     flv_read_packet,
 484     .extensions = "flv",
 485     .value = CODEC_ID_FLV1,
 486 };