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 #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:
  45             acodec->codec_id = acodec->bits_per_sample == 8 ? CODEC_ID_PCM_S8 :
  46 #ifdef WORDS_BIGENDIAN
  47                                 CODEC_ID_PCM_S16BE;
  48 #else
  49                                 CODEC_ID_PCM_S16LE;
  50 #endif
  51             break;
  52         case FLV_CODECID_PCM_LE:
  53             acodec->codec_id = acodec->bits_per_sample == 8 ? CODEC_ID_PCM_S8 : CODEC_ID_PCM_S16LE; break;
  54         case FLV_CODECID_ADPCM: acodec->codec_id = CODEC_ID_ADPCM_SWF;                              break;
  55         case FLV_CODECID_MP3  : acodec->codec_id = CODEC_ID_MP3      ; astream->need_parsing = AVSTREAM_PARSE_FULL; break;
  56         case FLV_CODECID_NELLYMOSER_8HZ_MONO:
  57             acodec->sample_rate = 8000; //in case metadata does not otherwise declare samplerate
  58         case FLV_CODECID_NELLYMOSER:
  59             acodec->codec_id = CODEC_ID_NELLYMOSER;
  60             break;
  61         default:
  62             av_log(s, AV_LOG_INFO, "Unsupported audio codec (%x)\n", flv_codecid >> FLV_AUDIO_CODECID_OFFSET);
  63             acodec->codec_tag = flv_codecid >> FLV_AUDIO_CODECID_OFFSET;
  64     }
  65 }
  66
  67 static int flv_set_video_codec(AVFormatContext *s, AVStream *vstream, int flv_codecid) {
  68     AVCodecContext *vcodec = vstream->codec;
  69     switch(flv_codecid) {
  70         case FLV_CODECID_H263  : vcodec->codec_id = CODEC_ID_FLV1   ; break;
  71         case FLV_CODECID_SCREEN: vcodec->codec_id = CODEC_ID_FLASHSV; break;
  72         case FLV_CODECID_VP6   : vcodec->codec_id = CODEC_ID_VP6F   ;
  73         case FLV_CODECID_VP6A  :
  74             if(flv_codecid == FLV_CODECID_VP6A)
  75                 vcodec->codec_id = CODEC_ID_VP6A;
  76             if(vcodec->extradata_size != 1) {
  77                 vcodec->extradata_size = 1;
  78                 vcodec->extradata = av_malloc(1);
  79             }
  80             vcodec->extradata[0] = get_byte(s->pb);
  81             return 1; // 1 byte body size adjustment for flv_read_packet()
  82         default:
  83             av_log(s, AV_LOG_INFO, "Unsupported video codec (%x)\n", flv_codecid);
  84             vcodec->codec_tag = flv_codecid;
  85     }
  86
  87     return 0;
  88 }
  89
  90 static int amf_get_string(ByteIOContext *ioc, char *buffer, int buffsize) {
  91     int length = get_be16(ioc);
  92     if(length >= buffsize) {
  93         url_fskip(ioc, length);
  94         return -1;
  95     }
  96
  97     get_buffer(ioc, buffer, length);
  98
  99     buffer[length] = '\0';
 100
 101     return length;
 102 }
 103
 104 static int amf_parse_object(AVFormatContext *s, AVStream *astream, AVStream *vstream, const char *key, unsigned int max_pos, int depth) {
 105     AVCodecContext *acodec, *vcodec;
 106     ByteIOContext *ioc;
 107     AMFDataType amf_type;
 108     char str_val[256];
 109     double num_val;
 110
 111     num_val = 0;
 112     ioc = s->pb;
 113
 114     amf_type = get_byte(ioc);
 115
 116     switch(amf_type) {
 117         case AMF_DATA_TYPE_NUMBER:
 118             num_val = av_int2dbl(get_be64(ioc)); break;
 119         case AMF_DATA_TYPE_BOOL:
 120             num_val = get_byte(ioc); break;
 121         case AMF_DATA_TYPE_STRING:
 122             if(amf_get_string(ioc, str_val, sizeof(str_val)) < 0)
 123                 return -1;
 124             break;
 125         case AMF_DATA_TYPE_OBJECT: {
 126             unsigned int keylen;
 127
 128             while(url_ftell(ioc) < max_pos - 2 && (keylen = get_be16(ioc))) {
 129                 url_fskip(ioc, keylen); //skip key string
 130                 if(amf_parse_object(s, NULL, NULL, NULL, max_pos, depth + 1) < 0)
 131                     return -1; //if we couldn't skip, bomb out.
 132             }
 133             if(get_byte(ioc) != AMF_END_OF_OBJECT)
 134                 return -1;
 135         }
 136             break;
 137         case AMF_DATA_TYPE_NULL:
 138         case AMF_DATA_TYPE_UNDEFINED:
 139         case AMF_DATA_TYPE_UNSUPPORTED:
 140             break; //these take up no additional space
 141         case AMF_DATA_TYPE_MIXEDARRAY:
 142             url_fskip(ioc, 4); //skip 32-bit max array index
 143             while(url_ftell(ioc) < max_pos - 2 && amf_get_string(ioc, str_val, sizeof(str_val)) > 0) {
 144                 //this is the only case in which we would want a nested parse to not skip over the object
 145                 if(amf_parse_object(s, astream, vstream, str_val, max_pos, depth + 1) < 0)
 146                     return -1;
 147             }
 148             if(get_byte(ioc) != AMF_END_OF_OBJECT)
 149                 return -1;
 150             break;
 151         case AMF_DATA_TYPE_ARRAY: {
 152             unsigned int arraylen, i;
 153
 154             arraylen = get_be32(ioc);
 155             for(i = 0; i < arraylen && url_ftell(ioc) < max_pos - 1; i++) {
 156                 if(amf_parse_object(s, NULL, NULL, NULL, max_pos, depth + 1) < 0)
 157                     return -1; //if we couldn't skip, bomb out.
 158             }
 159         }
 160             break;
 161         case AMF_DATA_TYPE_DATE:
 162             url_fskip(ioc, 8 + 2); //timestamp (double) and UTC offset (int16)
 163             break;
 164         default: //unsupported type, we couldn't skip
 165             return -1;
 166     }
 167
 168     if(depth == 1 && key) { //only look for metadata values when we are not nested and key != NULL
 169         acodec = astream ? astream->codec : NULL;
 170         vcodec = vstream ? vstream->codec : NULL;
 171
 172         if(amf_type == AMF_DATA_TYPE_BOOL) {
 173             if(!strcmp(key, "stereo") && acodec) acodec->channels = num_val > 0 ? 2 : 1;
 174         } else if(amf_type == AMF_DATA_TYPE_NUMBER) {
 175             if(!strcmp(key, "duration")) s->duration = num_val * AV_TIME_BASE;
 176 //            else if(!strcmp(key, "width")  && vcodec && num_val > 0) vcodec->width  = num_val;
 177 //            else if(!strcmp(key, "height") && vcodec && num_val > 0) vcodec->height = num_val;
 178             else if(!strcmp(key, "audiocodecid") && acodec && 0 <= (int)num_val)
 179                 flv_set_audio_codec(s, astream, (int)num_val << FLV_AUDIO_CODECID_OFFSET);
 180             else if(!strcmp(key, "videocodecid") && vcodec && 0 <= (int)num_val)
 181                 flv_set_video_codec(s, vstream, (int)num_val);
 182             else if(!strcmp(key, "audiosamplesize") && acodec && 0 < (int)num_val) {
 183                 acodec->bits_per_sample = num_val;
 184                 //we may have to rewrite a previously read codecid because FLV only marks PCM endianness.
 185                 if(num_val == 8 && (acodec->codec_id == CODEC_ID_PCM_S16BE || acodec->codec_id == CODEC_ID_PCM_S16LE))
 186                     acodec->codec_id = CODEC_ID_PCM_S8;
 187             }
 188             else if(!strcmp(key, "audiosamplerate") && acodec && num_val >= 0) {
 189                 //some tools, like FLVTool2, write consistently approximate metadata sample rates
 190                 if (!acodec->sample_rate) {
 191                     switch((int)num_val) {
 192                         case 44000: acodec->sample_rate = 44100  ; break;
 193                         case 22000: acodec->sample_rate = 22050  ; break;
 194                         case 11000: acodec->sample_rate = 11025  ; break;
 195                         case 5000 : acodec->sample_rate = 5512   ; break;
 196                         default   : acodec->sample_rate = num_val;
 197                     }
 198                 }
 199             }
 200         }
 201     }
 202
 203     return 0;
 204 }
 205
 206 static int flv_read_metabody(AVFormatContext *s, unsigned int next_pos) {
 207     AMFDataType type;
 208     AVStream *stream, *astream, *vstream;
 209     ByteIOContext *ioc;
 210     int i, keylen;
 211     char buffer[11]; //only needs to hold the string "onMetaData". Anything longer is something we don't want.
 212
 213     astream = NULL;
 214     vstream = NULL;
 215     keylen = 0;
 216     ioc = s->pb;
 217
 218     //first object needs to be "onMetaData" string
 219     type = get_byte(ioc);
 220     if(type != AMF_DATA_TYPE_STRING || amf_get_string(ioc, buffer, sizeof(buffer)) < 0 || strcmp(buffer, "onMetaData"))
 221         return -1;
 222
 223     //find the streams now so that amf_parse_object doesn't need to do the lookup every time it is called.
 224     for(i = 0; i < s->nb_streams; i++) {
 225         stream = s->streams[i];
 226         if     (stream->codec->codec_type == CODEC_TYPE_AUDIO) astream = stream;
 227         else if(stream->codec->codec_type == CODEC_TYPE_VIDEO) vstream = stream;
 228     }
 229
 230     //parse the second object (we want a mixed array)
 231     if(amf_parse_object(s, astream, vstream, buffer, next_pos, 0) < 0)
 232         return -1;
 233
 234     return 0;
 235 }
 236
 237 static AVStream *create_stream(AVFormatContext *s, int is_audio){
 238     AVStream *st = av_new_stream(s, is_audio);
 239     if (!st)
 240         return NULL;
 241     st->codec->codec_type = is_audio ? CODEC_TYPE_AUDIO : CODEC_TYPE_VIDEO;
 242     av_set_pts_info(st, 32, 1, 1000); /* 32 bit pts in ms */
 243     return st;
 244 }
 245
 246 static int flv_read_header(AVFormatContext *s,
 247                            AVFormatParameters *ap)
 248 {
 249     int offset, flags;
 250
 251     url_fskip(s->pb, 4);
 252     flags = get_byte(s->pb);
 253     /* old flvtool cleared this field */
 254     /* FIXME: better fix needed */
 255     if (!flags) {
 256         flags = FLV_HEADER_FLAG_HASVIDEO | FLV_HEADER_FLAG_HASAUDIO;
 257         av_log(s, AV_LOG_WARNING, "Broken FLV file, which says no streams present, this might fail\n");
 258     }
 259
 260     if((flags & (FLV_HEADER_FLAG_HASVIDEO|FLV_HEADER_FLAG_HASAUDIO))
 261              != (FLV_HEADER_FLAG_HASVIDEO|FLV_HEADER_FLAG_HASAUDIO))
 262         s->ctx_flags |= AVFMTCTX_NOHEADER;
 263
 264     if(flags & FLV_HEADER_FLAG_HASVIDEO){
 265         if(!create_stream(s, 0))
 266             return AVERROR(ENOMEM);
 267     }
 268     if(flags & FLV_HEADER_FLAG_HASAUDIO){
 269         if(!create_stream(s, 1))
 270             return AVERROR(ENOMEM);
 271     }
 272
 273     offset = get_be32(s->pb);
 274     url_fseek(s->pb, offset, SEEK_SET);
 275
 276     s->start_time = 0;
 277
 278     return 0;
 279 }
 280
 281 static int flv_read_packet(AVFormatContext *s, AVPacket *pkt)
 282 {
 283     int ret, i, type, size, flags, is_audio, next, pos;
 284     unsigned dts;
 285     AVStream *st = NULL;
 286
 287  for(;;){
 288     pos = url_ftell(s->pb);
 289     url_fskip(s->pb, 4); /* size of previous packet */
 290     type = get_byte(s->pb);
 291     size = get_be24(s->pb);
 292     dts = get_be24(s->pb);
 293     dts |= get_byte(s->pb) << 24;
 294 //    av_log(s, AV_LOG_DEBUG, "type:%d, size:%d, dts:%d\n", type, size, dts);
 295     if (url_feof(s->pb))
 296         return AVERROR(EIO);
 297     url_fskip(s->pb, 3); /* stream id, always 0 */
 298     flags = 0;
 299
 300     if(size == 0)
 301         continue;
 302
 303     next= size + url_ftell(s->pb);
 304
 305     if (type == FLV_TAG_TYPE_AUDIO) {
 306         is_audio=1;
 307         flags = get_byte(s->pb);
 308     } else if (type == FLV_TAG_TYPE_VIDEO) {
 309         is_audio=0;
 310         flags = get_byte(s->pb);
 311     } else {
 312         if (type == FLV_TAG_TYPE_META && size > 13+1+4)
 313             flv_read_metabody(s, next);
 314         else /* skip packet */
 315             av_log(s, AV_LOG_ERROR, "skipping flv packet: type %d, size %d, flags %d\n", type, size, flags);
 316         url_fseek(s->pb, next, SEEK_SET);
 317         continue;
 318     }
 319
 320     /* now find stream */
 321     for(i=0;i<s->nb_streams;i++) {
 322         st = s->streams[i];
 323         if (st->id == is_audio)
 324             break;
 325     }
 326     if(i == s->nb_streams){
 327         av_log(NULL, AV_LOG_ERROR, "invalid stream\n");
 328         st= create_stream(s, is_audio);
 329         s->ctx_flags &= ~AVFMTCTX_NOHEADER;
 330     }
 331 //    av_log(NULL, AV_LOG_DEBUG, "%d %X %d \n", is_audio, flags, st->discard);
 332     if(  (st->discard >= AVDISCARD_NONKEY && !((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY ||         is_audio))
 333        ||(st->discard >= AVDISCARD_BIDIR  &&  ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_DISP_INTER && !is_audio))
 334        || st->discard >= AVDISCARD_ALL
 335        ){
 336         url_fseek(s->pb, next, SEEK_SET);
 337         continue;
 338     }
 339     if ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY)
 340         av_add_index_entry(st, pos, dts, size, 0, AVINDEX_KEYFRAME);
 341     break;
 342  }
 343
 344     // if not streamed and no duration from metadata then seek to end to find the duration from the timestamps
 345     if(!url_is_streamed(s->pb) && s->duration==AV_NOPTS_VALUE){
 346         int size;
 347         const int pos= url_ftell(s->pb);
 348         const int fsize= url_fsize(s->pb);
 349         url_fseek(s->pb, fsize-4, SEEK_SET);
 350         size= get_be32(s->pb);
 351         url_fseek(s->pb, fsize-3-size, SEEK_SET);
 352         if(size == get_be24(s->pb) + 11){
 353             s->duration= get_be24(s->pb) * (int64_t)AV_TIME_BASE / 1000;
 354         }
 355         url_fseek(s->pb, pos, SEEK_SET);
 356     }
 357
 358     if(is_audio){
 359         if(!st->codec->sample_rate || !st->codec->bits_per_sample || (!st->codec->codec_id && !st->codec->codec_tag)) {
 360             st->codec->channels = (flags & FLV_AUDIO_CHANNEL_MASK) == FLV_STEREO ? 2 : 1;
 361             if((flags & FLV_AUDIO_CODECID_MASK) == FLV_CODECID_NELLYMOSER_8HZ_MONO)
 362                 st->codec->sample_rate= 8000;
 363             else
 364                 st->codec->sample_rate = (44100 << ((flags & FLV_AUDIO_SAMPLERATE_MASK) >> FLV_AUDIO_SAMPLERATE_OFFSET) >> 3);
 365             st->codec->bits_per_sample = (flags & FLV_AUDIO_SAMPLESIZE_MASK) ? 16 : 8;
 366             flv_set_audio_codec(s, st, flags & FLV_AUDIO_CODECID_MASK);
 367         }
 368     }else{
 369         size -= flv_set_video_codec(s, st, flags & FLV_VIDEO_CODECID_MASK);
 370     }
 371
 372     ret= av_get_packet(s->pb, pkt, size - 1);
 373     if (ret <= 0) {
 374         return AVERROR(EIO);
 375     }
 376     /* note: we need to modify the packet size here to handle the last
 377        packet */
 378     pkt->size = ret;
 379     pkt->dts = dts;
 380     pkt->stream_index = st->index;
 381
 382     if (is_audio || ((flags & FLV_VIDEO_FRAMETYPE_MASK) == FLV_FRAME_KEY))
 383         pkt->flags |= PKT_FLAG_KEY;
 384
 385     return ret;
 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     .extensions = "flv",
 396     .value = CODEC_ID_FLV1,
 397 };