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/*
* Copyright (C) 2019 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.wav;
import org.mozilla.thirdparty.com.google.android.exoplayer2.C;
import org.mozilla.thirdparty.com.google.android.exoplayer2.extractor.SeekMap;
import org.mozilla.thirdparty.com.google.android.exoplayer2.extractor.SeekPoint;
import org.mozilla.thirdparty.com.google.android.exoplayer2.util.Util;
/* package */ final class WavSeekMap implements SeekMap {
private final WavHeader wavHeader;
private final int framesPerBlock;
private final long firstBlockPosition;
private final long blockCount;
private final long durationUs;
public WavSeekMap(
WavHeader wavHeader, int framesPerBlock, long dataStartPosition, long dataEndPosition) {
this.wavHeader = wavHeader;
this.framesPerBlock = framesPerBlock;
this.firstBlockPosition = dataStartPosition;
this.blockCount = (dataEndPosition - dataStartPosition) / wavHeader.blockSize;
durationUs = blockIndexToTimeUs(blockCount);
}
@Override
public boolean isSeekable() {
return true;
}
@Override
public long getDurationUs() {
return durationUs;
}
@Override
public SeekPoints getSeekPoints(long timeUs) {
// Calculate the containing block index, constraining to valid indices.
long blockIndex = (timeUs * wavHeader.frameRateHz) / (C.MICROS_PER_SECOND * framesPerBlock);
blockIndex = Util.constrainValue(blockIndex, 0, blockCount - 1);
long seekPosition = firstBlockPosition + (blockIndex * wavHeader.blockSize);
long seekTimeUs = blockIndexToTimeUs(blockIndex);
SeekPoint seekPoint = new SeekPoint(seekTimeUs, seekPosition);
if (seekTimeUs >= timeUs || blockIndex == blockCount - 1) {
return new SeekPoints(seekPoint);
} else {
long secondBlockIndex = blockIndex + 1;
long secondSeekPosition = firstBlockPosition + (secondBlockIndex * wavHeader.blockSize);
long secondSeekTimeUs = blockIndexToTimeUs(secondBlockIndex);
SeekPoint secondSeekPoint = new SeekPoint(secondSeekTimeUs, secondSeekPosition);
return new SeekPoints(seekPoint, secondSeekPoint);
}
}
private long blockIndexToTimeUs(long blockIndex) {
return Util.scaleLargeTimestamp(
blockIndex * framesPerBlock, C.MICROS_PER_SECOND, wavHeader.frameRateHz);
}
}
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