// @VisibleForTesting
/* package */ VorbisSetup readSetupHeaders(ExtractorInput input, ParsableByteArray scratch)
throws IOException, InterruptedException {
if (vorbisIdHeader == null) {
oggReader.readPacket(input, scratch);
vorbisIdHeader = VorbisUtil.readVorbisIdentificationHeader(scratch);
scratch.reset();
}
if (commentHeader == null) {
oggReader.readPacket(input, scratch);
commentHeader = VorbisUtil.readVorbisCommentHeader(scratch);
scratch.reset();
}
oggReader.readPacket(input, scratch);
// the third packet contains the setup header
byte[] setupHeaderData = new byte[scratch.limit()];
// raw data of vorbis setup header has to be passed to decoder as CSD buffer #2
System.arraycopy(scratch.data, 0, setupHeaderData, 0, scratch.limit());
// partially decode setup header to get the modes
Mode[] modes = VorbisUtil.readVorbisModes(scratch, vorbisIdHeader.channels);
// we need the ilog of modes all the time when extracting, so we compute it once
int iLogModes = VorbisUtil.iLog(modes.length - 1);
scratch.reset();
return new VorbisSetup(vorbisIdHeader, commentHeader, setupHeaderData, modes, iLogModes);
}
@Override
public void seek() {
oggReader.reset();
previousPacketBlockSize = -1;
elapsedSamples = 0;
seenFirstAudioPacket = false;
scratch.reset();
}
@Override
public int read(ExtractorInput input, PositionHolder seekPosition)
throws IOException, InterruptedException {
if (vorbisSetup == null) {
vorbisSetup = readSetupHeaders(input, scratch);
ArrayList<byte[]> codecInitialisationData = new ArrayList<>();
codecInitialisationData.clear();
codecInitialisationData.add(vorbisSetup.idHeader.data);
codecInitialisationData.add(vorbisSetup.setupHeaderData);
long duration =
input.getLength() == C.LENGTH_UNBOUNDED
? C.UNKNOWN_TIME_US
: input.getLength() * 8000000 / vorbisSetup.idHeader.getApproximateBitrate();
trackOutput.format(
MediaFormat.createAudioFormat(
null,
MimeTypes.AUDIO_VORBIS,
this.vorbisSetup.idHeader.bitrateNominal,
OGG_MAX_SEGMENT_SIZE * 255,
duration,
this.vorbisSetup.idHeader.channels,
(int) this.vorbisSetup.idHeader.sampleRate,
codecInitialisationData,
null));
}
if (oggReader.readPacket(input, scratch)) {
// if this is an audio packet...
if ((scratch.data[0] & 0x01) != 1) {
// ... we need to decode the block size
int packetBlockSize = decodeBlockSize(scratch.data[0], vorbisSetup);
// a packet contains samples produced from overlapping the previous and current frame data
// (https://www.xiph.org/vorbis/doc/Vorbis_I_spec.html#x1-350001.3.2)
int samplesInPacket =
seenFirstAudioPacket ? (packetBlockSize + previousPacketBlockSize) / 4 : 0;
// codec expects the number of samples appended to audio data
appendNumberOfSamples(scratch, samplesInPacket);
// calculate time and send audio data to codec
long timeUs = elapsedSamples * C.MICROS_PER_SECOND / vorbisSetup.idHeader.sampleRate;
trackOutput.sampleData(scratch, scratch.limit());
trackOutput.sampleMetadata(timeUs, C.SAMPLE_FLAG_SYNC, scratch.limit(), 0, null);
// update state in members for next iteration
seenFirstAudioPacket = true;
elapsedSamples += samplesInPacket;
previousPacketBlockSize = packetBlockSize;
}
scratch.reset();
return RESULT_CONTINUE;
}
return RESULT_END_OF_INPUT;
}
@Override
public boolean sniff(ExtractorInput input) throws IOException, InterruptedException {
try {
OggReader.PageHeader header = new OggReader.PageHeader();
OggReader.populatePageHeader(input, header, scratch, true);
if ((header.type & 0x02) != 0x02) {
throw new ParserException("expected page to be first page of a logical stream");
}
input.resetPeekPosition();
} catch (ParserException e) {
Log.e(TAG, e.getMessage());
return false;
}
return true;
}