int ff_get_wav_header(AVIOContext *pb, AVCodecContext *codec, int size) { int id; id = avio_rl16(pb); codec->codec_type = AVMEDIA_TYPE_AUDIO; codec->channels = avio_rl16(pb); codec->sample_rate = avio_rl32(pb); codec->bit_rate = avio_rl32(pb) * 8; codec->block_align = avio_rl16(pb); if (size == 14) { /* We're dealing with plain vanilla WAVEFORMAT */ codec->bits_per_coded_sample = 8; }else codec->bits_per_coded_sample = avio_rl16(pb); if (id == 0xFFFE) { codec->codec_tag = 0; } else { codec->codec_tag = id; codec->codec_id = ff_wav_codec_get_id(id, codec->bits_per_coded_sample); } if (size >= 18) { /* We're obviously dealing with WAVEFORMATEX */ int cbSize = avio_rl16(pb); /* cbSize */ size -= 18; cbSize = FFMIN(size, cbSize); if (cbSize >= 22 && id == 0xfffe) { /* WAVEFORMATEXTENSIBLE */ ff_asf_guid subformat; codec->bits_per_coded_sample = avio_rl16(pb); codec->channel_layout = avio_rl32(pb); /* dwChannelMask */ ff_get_guid(pb, &subformat); if (!memcmp(subformat + 4, (const uint8_t[]){FF_MEDIASUBTYPE_BASE_GUID}, 12)) { codec->codec_tag = AV_RL32(subformat); codec->codec_id = ff_wav_codec_get_id(codec->codec_tag, codec->bits_per_coded_sample); } else { codec->codec_id = ff_codec_guid_get_id(ff_codec_wav_guids, subformat); if (!codec->codec_id) av_log(codec, AV_LOG_WARNING, "unknown subformat:"FF_PRI_GUID"\n", FF_ARG_GUID(subformat)); } cbSize -= 22; size -= 22; } codec->extradata_size = cbSize; if (cbSize > 0) { av_free(codec->extradata); codec->extradata = av_mallocz(codec->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE); if (!codec->extradata) return AVERROR(ENOMEM); avio_read(pb, codec->extradata, codec->extradata_size); size -= cbSize; } /* It is possible for the chunk to contain garbage at the end */ if (size > 0) avio_skip(pb, size); } if (codec->codec_id == CODEC_ID_AAC_LATM) { /* channels and sample_rate values are those prior to applying SBR and/or PS */ codec->channels = 0; codec->sample_rate = 0; } /* override bits_per_coded_sample for G.726 */ if (codec->codec_id == CODEC_ID_ADPCM_G726) codec->bits_per_coded_sample = codec->bit_rate / codec->sample_rate; return 0; }