mirror of https://github.com/NekoX-Dev/NekoX.git
181 lines
6.7 KiB
Java
181 lines
6.7 KiB
Java
/*
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* Copyright (C) 2017 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.google.android.exoplayer2.audio;
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import com.google.android.exoplayer2.C;
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import com.google.android.exoplayer2.util.Util;
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import java.nio.ByteBuffer;
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/** Audio processor for trimming samples from the start/end of data. */
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/* package */ final class TrimmingAudioProcessor extends BaseAudioProcessor {
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@C.PcmEncoding private static final int OUTPUT_ENCODING = C.ENCODING_PCM_16BIT;
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private int trimStartFrames;
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private int trimEndFrames;
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private boolean reconfigurationPending;
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private int pendingTrimStartBytes;
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private byte[] endBuffer;
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private int endBufferSize;
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private long trimmedFrameCount;
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/** Creates a new audio processor for trimming samples from the start/end of data. */
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public TrimmingAudioProcessor() {
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endBuffer = Util.EMPTY_BYTE_ARRAY;
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}
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/**
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* Sets the number of audio frames to trim from the start and end of audio passed to this
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* processor. After calling this method, call {@link #configure(AudioFormat)} to apply the new
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* trimming frame counts.
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*
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* @param trimStartFrames The number of audio frames to trim from the start of audio.
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* @param trimEndFrames The number of audio frames to trim from the end of audio.
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* @see AudioSink#configure(int, int, int, int, int[], int, int)
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*/
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public void setTrimFrameCount(int trimStartFrames, int trimEndFrames) {
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this.trimStartFrames = trimStartFrames;
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this.trimEndFrames = trimEndFrames;
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}
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/** Sets the trimmed frame count returned by {@link #getTrimmedFrameCount()} to zero. */
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public void resetTrimmedFrameCount() {
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trimmedFrameCount = 0;
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}
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/**
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* Returns the number of audio frames trimmed since the last call to {@link
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* #resetTrimmedFrameCount()}.
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*/
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public long getTrimmedFrameCount() {
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return trimmedFrameCount;
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}
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@Override
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public AudioFormat onConfigure(AudioFormat inputAudioFormat)
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throws UnhandledAudioFormatException {
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if (inputAudioFormat.encoding != OUTPUT_ENCODING) {
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throw new UnhandledAudioFormatException(inputAudioFormat);
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}
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reconfigurationPending = true;
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return trimStartFrames != 0 || trimEndFrames != 0 ? inputAudioFormat : AudioFormat.NOT_SET;
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}
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@Override
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public void queueInput(ByteBuffer inputBuffer) {
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int position = inputBuffer.position();
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int limit = inputBuffer.limit();
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int remaining = limit - position;
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if (remaining == 0) {
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return;
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}
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// Trim any pending start bytes from the input buffer.
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int trimBytes = Math.min(remaining, pendingTrimStartBytes);
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trimmedFrameCount += trimBytes / inputAudioFormat.bytesPerFrame;
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pendingTrimStartBytes -= trimBytes;
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inputBuffer.position(position + trimBytes);
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if (pendingTrimStartBytes > 0) {
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// Nothing to output yet.
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return;
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}
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remaining -= trimBytes;
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// endBuffer must be kept as full as possible, so that we trim the right amount of media if we
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// don't receive any more input. After taking into account the number of bytes needed to keep
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// endBuffer as full as possible, the output should be any surplus bytes currently in endBuffer
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// followed by any surplus bytes in the new inputBuffer.
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int remainingBytesToOutput = endBufferSize + remaining - endBuffer.length;
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ByteBuffer buffer = replaceOutputBuffer(remainingBytesToOutput);
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// Output from endBuffer.
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int endBufferBytesToOutput = Util.constrainValue(remainingBytesToOutput, 0, endBufferSize);
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buffer.put(endBuffer, 0, endBufferBytesToOutput);
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remainingBytesToOutput -= endBufferBytesToOutput;
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// Output from inputBuffer, restoring its limit afterwards.
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int inputBufferBytesToOutput = Util.constrainValue(remainingBytesToOutput, 0, remaining);
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inputBuffer.limit(inputBuffer.position() + inputBufferBytesToOutput);
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buffer.put(inputBuffer);
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inputBuffer.limit(limit);
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remaining -= inputBufferBytesToOutput;
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// Compact endBuffer, then repopulate it using the new input.
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endBufferSize -= endBufferBytesToOutput;
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System.arraycopy(endBuffer, endBufferBytesToOutput, endBuffer, 0, endBufferSize);
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inputBuffer.get(endBuffer, endBufferSize, remaining);
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endBufferSize += remaining;
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buffer.flip();
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}
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@Override
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public ByteBuffer getOutput() {
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if (super.isEnded() && endBufferSize > 0) {
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// Because audio processors may be drained in the middle of the stream we assume that the
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// contents of the end buffer need to be output. For gapless transitions, configure will
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// always be called, so the end buffer is cleared in onQueueEndOfStream.
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replaceOutputBuffer(endBufferSize).put(endBuffer, 0, endBufferSize).flip();
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endBufferSize = 0;
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}
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return super.getOutput();
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}
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@Override
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public boolean isEnded() {
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return super.isEnded() && endBufferSize == 0;
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}
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@Override
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protected void onQueueEndOfStream() {
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if (reconfigurationPending) {
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// Trim audio in the end buffer.
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if (endBufferSize > 0) {
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trimmedFrameCount += endBufferSize / inputAudioFormat.bytesPerFrame;
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}
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endBufferSize = 0;
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}
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}
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@Override
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protected void onFlush() {
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if (reconfigurationPending) {
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// Flushing activates the new configuration, so prepare to trim bytes from the start/end.
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reconfigurationPending = false;
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endBuffer = new byte[trimEndFrames * inputAudioFormat.bytesPerFrame];
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pendingTrimStartBytes = trimStartFrames * inputAudioFormat.bytesPerFrame;
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}
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// TODO(internal b/77292509): Flushing occurs to activate a configuration (handled above) but
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// also when seeking within a stream. This implementation currently doesn't handle seek to start
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// (where we need to trim at the start again), nor seeks to non-zero positions before start
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// trimming has occurred (where we should set pendingTrimStartBytes to zero). These cases can be
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// fixed by trimming in queueInput based on timestamp, once that information is available.
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// Any data in the end buffer should no longer be output if we are playing from a different
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// position, so discard it and refill the buffer using new input.
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endBufferSize = 0;
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}
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@Override
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protected void onReset() {
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endBuffer = Util.EMPTY_BYTE_ARRAY;
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}
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}
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