mirror of https://github.com/NekoX-Dev/NekoX.git
100 lines
3.4 KiB
Java
100 lines
3.4 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 androidx.annotation.Nullable;
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import com.google.android.exoplayer2.C;
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import com.google.android.exoplayer2.util.Assertions;
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import java.nio.ByteBuffer;
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/**
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* An {@link AudioProcessor} that applies a mapping from input channels onto specified output
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* channels. This can be used to reorder, duplicate or discard channels.
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*/
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@SuppressWarnings("nullness:initialization.fields.uninitialized")
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/* package */ final class ChannelMappingAudioProcessor extends BaseAudioProcessor {
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@Nullable private int[] pendingOutputChannels;
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@Nullable private int[] outputChannels;
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/**
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* Resets the channel mapping. After calling this method, call {@link #configure(AudioFormat)} to
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* start using the new channel map.
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*
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* @param outputChannels The mapping from input to output channel indices, or {@code null} to
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* leave the input unchanged.
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* @see AudioSink#configure(int, int, int, int, int[], int, int)
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*/
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public void setChannelMap(@Nullable int[] outputChannels) {
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pendingOutputChannels = outputChannels;
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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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@Nullable int[] outputChannels = pendingOutputChannels;
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if (outputChannels == null) {
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return AudioFormat.NOT_SET;
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}
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if (inputAudioFormat.encoding != C.ENCODING_PCM_16BIT) {
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throw new UnhandledAudioFormatException(inputAudioFormat);
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}
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boolean active = inputAudioFormat.channelCount != outputChannels.length;
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for (int i = 0; i < outputChannels.length; i++) {
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int channelIndex = outputChannels[i];
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if (channelIndex >= inputAudioFormat.channelCount) {
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throw new UnhandledAudioFormatException(inputAudioFormat);
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}
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active |= (channelIndex != i);
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}
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return active
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? new AudioFormat(inputAudioFormat.sampleRate, outputChannels.length, C.ENCODING_PCM_16BIT)
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: 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[] outputChannels = Assertions.checkNotNull(this.outputChannels);
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int position = inputBuffer.position();
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int limit = inputBuffer.limit();
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int frameCount = (limit - position) / inputAudioFormat.bytesPerFrame;
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int outputSize = frameCount * outputAudioFormat.bytesPerFrame;
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ByteBuffer buffer = replaceOutputBuffer(outputSize);
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while (position < limit) {
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for (int channelIndex : outputChannels) {
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buffer.putShort(inputBuffer.getShort(position + 2 * channelIndex));
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}
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position += inputAudioFormat.bytesPerFrame;
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}
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inputBuffer.position(limit);
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buffer.flip();
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}
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@Override
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protected void onFlush() {
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outputChannels = pendingOutputChannels;
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}
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@Override
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protected void onReset() {
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outputChannels = null;
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pendingOutputChannels = null;
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}
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}
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