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/*
* Copyright (C) 2016 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.mozilla.thirdparty.com.google.android.exoplayer2.extractor.ogg;
import org.mozilla.thirdparty.com.google.android.exoplayer2.extractor.ExtractorInput;
import org.mozilla.thirdparty.com.google.android.exoplayer2.extractor.FlacFrameReader;
import org.mozilla.thirdparty.com.google.android.exoplayer2.extractor.FlacMetadataReader;
import org.mozilla.thirdparty.com.google.android.exoplayer2.extractor.FlacSeekTableSeekMap;
import org.mozilla.thirdparty.com.google.android.exoplayer2.extractor.SeekMap;
import org.mozilla.thirdparty.com.google.android.exoplayer2.util.Assertions;
import org.mozilla.thirdparty.com.google.android.exoplayer2.util.FlacConstants;
import org.mozilla.thirdparty.com.google.android.exoplayer2.util.FlacStreamMetadata;
import org.mozilla.thirdparty.com.google.android.exoplayer2.util.ParsableByteArray;
import org.mozilla.thirdparty.com.google.android.exoplayer2.util.Util;
import java.io.IOException;
import java.util.Arrays;
/**
* {@link StreamReader} to extract Flac data out of Ogg byte stream.
*/
/* package */ final class FlacReader extends StreamReader {
private static final byte AUDIO_PACKET_TYPE = (byte) 0xFF;
private static final int FRAME_HEADER_SAMPLE_NUMBER_OFFSET = 4;
private FlacStreamMetadata streamMetadata;
private FlacOggSeeker flacOggSeeker;
public static boolean verifyBitstreamType(ParsableByteArray data) {
return data.bytesLeft() >= 5 && data.readUnsignedByte() == 0x7F && // packet type
data.readUnsignedInt() == 0x464C4143; // ASCII signature "FLAC"
}
@Override
protected void reset(boolean headerData) {
super.reset(headerData);
if (headerData) {
streamMetadata = null;
flacOggSeeker = null;
}
}
private static boolean isAudioPacket(byte[] data) {
return data[0] == AUDIO_PACKET_TYPE;
}
@Override
protected long preparePayload(ParsableByteArray packet) {
if (!isAudioPacket(packet.data)) {
return -1;
}
return getFlacFrameBlockSize(packet);
}
@Override
protected boolean readHeaders(ParsableByteArray packet, long position, SetupData setupData) {
byte[] data = packet.data;
if (streamMetadata == null) {
streamMetadata = new FlacStreamMetadata(data, 17);
byte[] metadata = Arrays.copyOfRange(data, 9, packet.limit());
setupData.format = streamMetadata.getFormat(metadata, /* id3Metadata= */ null);
} else if ((data[0] & 0x7F) == FlacConstants.METADATA_TYPE_SEEK_TABLE) {
flacOggSeeker = new FlacOggSeeker();
FlacStreamMetadata.SeekTable seekTable =
FlacMetadataReader.readSeekTableMetadataBlock(packet);
streamMetadata = streamMetadata.copyWithSeekTable(seekTable);
} else if (isAudioPacket(data)) {
if (flacOggSeeker != null) {
flacOggSeeker.setFirstFrameOffset(position);
setupData.oggSeeker = flacOggSeeker;
}
return false;
}
return true;
}
private int getFlacFrameBlockSize(ParsableByteArray packet) {
int blockSizeKey = (packet.data[2] & 0xFF) >> 4;
if (blockSizeKey == 6 || blockSizeKey == 7) {
// Skip the sample number.
packet.skipBytes(FRAME_HEADER_SAMPLE_NUMBER_OFFSET);
packet.readUtf8EncodedLong();
}
int result = FlacFrameReader.readFrameBlockSizeSamplesFromKey(packet, blockSizeKey);
packet.setPosition(0);
return result;
}
private class FlacOggSeeker implements OggSeeker {
private long firstFrameOffset;
private long pendingSeekGranule;
public FlacOggSeeker() {
firstFrameOffset = -1;
pendingSeekGranule = -1;
}
public void setFirstFrameOffset(long firstFrameOffset) {
this.firstFrameOffset = firstFrameOffset;
}
@Override
public long read(ExtractorInput input) throws IOException, InterruptedException {
if (pendingSeekGranule >= 0) {
long result = -(pendingSeekGranule + 2);
pendingSeekGranule = -1;
return result;
}
return -1;
}
@Override
public void startSeek(long targetGranule) {
Assertions.checkNotNull(streamMetadata.seekTable);
long[] seekPointGranules = streamMetadata.seekTable.pointSampleNumbers;
int index = Util.binarySearchFloor(seekPointGranules, targetGranule, true, true);
pendingSeekGranule = seekPointGranules[index];
}
@Override
public SeekMap createSeekMap() {
Assertions.checkState(firstFrameOffset != -1);
return new FlacSeekTableSeekMap(streamMetadata, firstFrameOffset);
}
}
}
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