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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.ts;
import static org.mozilla.thirdparty.com.google.android.exoplayer2.extractor.ts.TsPayloadReader.FLAG_DATA_ALIGNMENT_INDICATOR;
import static org.mozilla.thirdparty.com.google.android.exoplayer2.metadata.id3.Id3Decoder.ID3_HEADER_LENGTH;
import org.mozilla.thirdparty.com.google.android.exoplayer2.C;
import org.mozilla.thirdparty.com.google.android.exoplayer2.Format;
import org.mozilla.thirdparty.com.google.android.exoplayer2.extractor.ExtractorOutput;
import org.mozilla.thirdparty.com.google.android.exoplayer2.extractor.TrackOutput;
import org.mozilla.thirdparty.com.google.android.exoplayer2.extractor.ts.TsPayloadReader.TrackIdGenerator;
import org.mozilla.thirdparty.com.google.android.exoplayer2.util.Log;
import org.mozilla.thirdparty.com.google.android.exoplayer2.util.MimeTypes;
import org.mozilla.thirdparty.com.google.android.exoplayer2.util.ParsableByteArray;
/**
* Parses ID3 data and extracts individual text information frames.
*/
public final class Id3Reader implements ElementaryStreamReader {
private static final String TAG = "Id3Reader";
private final ParsableByteArray id3Header;
private TrackOutput output;
// State that should be reset on seek.
private boolean writingSample;
// Per sample state that gets reset at the start of each sample.
private long sampleTimeUs;
private int sampleSize;
private int sampleBytesRead;
public Id3Reader() {
id3Header = new ParsableByteArray(ID3_HEADER_LENGTH);
}
@Override
public void seek() {
writingSample = false;
}
@Override
public void createTracks(ExtractorOutput extractorOutput, TrackIdGenerator idGenerator) {
idGenerator.generateNewId();
output = extractorOutput.track(idGenerator.getTrackId(), C.TRACK_TYPE_METADATA);
output.format(Format.createSampleFormat(idGenerator.getFormatId(), MimeTypes.APPLICATION_ID3,
null, Format.NO_VALUE, null));
}
@Override
public void packetStarted(long pesTimeUs, @TsPayloadReader.Flags int flags) {
if ((flags & FLAG_DATA_ALIGNMENT_INDICATOR) == 0) {
return;
}
writingSample = true;
sampleTimeUs = pesTimeUs;
sampleSize = 0;
sampleBytesRead = 0;
}
@Override
public void consume(ParsableByteArray data) {
if (!writingSample) {
return;
}
int bytesAvailable = data.bytesLeft();
if (sampleBytesRead < ID3_HEADER_LENGTH) {
// We're still reading the ID3 header.
int headerBytesAvailable = Math.min(bytesAvailable, ID3_HEADER_LENGTH - sampleBytesRead);
System.arraycopy(data.data, data.getPosition(), id3Header.data, sampleBytesRead,
headerBytesAvailable);
if (sampleBytesRead + headerBytesAvailable == ID3_HEADER_LENGTH) {
// We've finished reading the ID3 header. Extract the sample size.
id3Header.setPosition(0);
if ('I' != id3Header.readUnsignedByte() || 'D' != id3Header.readUnsignedByte()
|| '3' != id3Header.readUnsignedByte()) {
Log.w(TAG, "Discarding invalid ID3 tag");
writingSample = false;
return;
}
id3Header.skipBytes(3); // version (2) + flags (1)
sampleSize = ID3_HEADER_LENGTH + id3Header.readSynchSafeInt();
}
}
// Write data to the output.
int bytesToWrite = Math.min(bytesAvailable, sampleSize - sampleBytesRead);
output.sampleData(data, bytesToWrite);
sampleBytesRead += bytesToWrite;
}
@Override
public void packetFinished() {
if (!writingSample || sampleSize == 0 || sampleBytesRead != sampleSize) {
return;
}
output.sampleMetadata(sampleTimeUs, C.BUFFER_FLAG_KEY_FRAME, sampleSize, 0, null);
writingSample = false;
}
}
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