static int flac_read_header(AVFormatContext *s, AVFormatParameters *ap) { int ret, metadata_last=0, metadata_type, metadata_size, found_streaminfo=0; uint8_t header[4]; uint8_t *buffer=NULL; AVStream *st = avformat_new_stream(s, NULL); if (!st) return AVERROR(ENOMEM); st->codec->codec_type = AVMEDIA_TYPE_AUDIO; st->codec->codec_id = CODEC_ID_FLAC; st->need_parsing = AVSTREAM_PARSE_FULL; /* the parameters will be extracted from the compressed bitstream */ /* if fLaC marker is not found, assume there is no header */ if (avio_rl32(s->pb) != MKTAG('f','L','a','C')) { avio_seek(s->pb, -4, SEEK_CUR); return 0; } /* process metadata blocks */ while (!s->pb->eof_reached && !metadata_last) { avio_read(s->pb, header, 4); avpriv_flac_parse_block_header(header, &metadata_last, &metadata_type, &metadata_size); switch (metadata_type) { /* allocate and read metadata block for supported types */ case FLAC_METADATA_TYPE_STREAMINFO: case FLAC_METADATA_TYPE_CUESHEET: case FLAC_METADATA_TYPE_VORBIS_COMMENT: buffer = av_mallocz(metadata_size + FF_INPUT_BUFFER_PADDING_SIZE); if (!buffer) { return AVERROR(ENOMEM); } if (avio_read(s->pb, buffer, metadata_size) != metadata_size) { av_freep(&buffer); return AVERROR(EIO); } break; /* skip metadata block for unsupported types */ default: ret = avio_skip(s->pb, metadata_size); if (ret < 0) return ret; } if (metadata_type == FLAC_METADATA_TYPE_STREAMINFO) { FLACStreaminfo si; /* STREAMINFO can only occur once */ if (found_streaminfo) { av_freep(&buffer); return AVERROR_INVALIDDATA; } if (metadata_size != FLAC_STREAMINFO_SIZE) { av_freep(&buffer); return AVERROR_INVALIDDATA; } found_streaminfo = 1; st->codec->extradata = buffer; st->codec->extradata_size = metadata_size; buffer = NULL; /* get codec params from STREAMINFO header */ avpriv_flac_parse_streaminfo(st->codec, &si, st->codec->extradata); /* set time base and duration */ if (si.samplerate > 0) { avpriv_set_pts_info(st, 64, 1, si.samplerate); if (si.samples > 0) st->duration = si.samples; } } else if (metadata_type == FLAC_METADATA_TYPE_CUESHEET) { uint8_t isrc[13]; uint64_t start; const uint8_t *offset; int i, j, chapters, track, ti; if (metadata_size < 431) return AVERROR_INVALIDDATA; offset = buffer + 395; chapters = bytestream_get_byte(&offset) - 1; if (chapters <= 0) return AVERROR_INVALIDDATA; for (i = 0; i < chapters; i++) { if (offset + 36 - buffer > metadata_size) return AVERROR_INVALIDDATA; start = bytestream_get_be64(&offset); track = bytestream_get_byte(&offset); bytestream_get_buffer(&offset, isrc, 12); isrc[12] = 0; offset += 14; ti = bytestream_get_byte(&offset); if (ti <= 0) return AVERROR_INVALIDDATA; for (j = 0; j < ti; j++) offset += 12; avpriv_new_chapter(s, track, st->time_base, start, AV_NOPTS_VALUE, isrc); } } else { /* STREAMINFO must be the first block */ if (!found_streaminfo) { av_freep(&buffer); return AVERROR_INVALIDDATA; } /* process supported blocks other than STREAMINFO */ if (metadata_type == FLAC_METADATA_TYPE_VORBIS_COMMENT) { if (ff_vorbis_comment(s, &s->metadata, buffer, metadata_size)) { av_log(s, AV_LOG_WARNING, "error parsing VorbisComment metadata\n"); } } av_freep(&buffer); } } return 0; }