mirror of https://github.com/NekoX-Dev/NekoX.git
149 lines
5.9 KiB
Java
149 lines
5.9 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.Format;
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import com.google.android.exoplayer2.util.Util;
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import java.nio.ByteBuffer;
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import java.nio.ByteOrder;
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/**
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* Interface for audio processors, which take audio data as input and transform it, potentially
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* modifying its channel count, encoding and/or sample rate.
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*
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* <p>In addition to being able to modify the format of audio, implementations may allow parameters
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* to be set that affect the output audio and whether the processor is active/inactive.
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*/
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public interface AudioProcessor {
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/** PCM audio format that may be handled by an audio processor. */
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final class AudioFormat {
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public static final AudioFormat NOT_SET =
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new AudioFormat(
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/* sampleRate= */ Format.NO_VALUE,
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/* channelCount= */ Format.NO_VALUE,
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/* encoding= */ Format.NO_VALUE);
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/** The sample rate in Hertz. */
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public final int sampleRate;
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/** The number of interleaved channels. */
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public final int channelCount;
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/** The type of linear PCM encoding. */
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@C.PcmEncoding public final int encoding;
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/** The number of bytes used to represent one audio frame. */
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public final int bytesPerFrame;
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public AudioFormat(int sampleRate, int channelCount, @C.PcmEncoding int encoding) {
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this.sampleRate = sampleRate;
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this.channelCount = channelCount;
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this.encoding = encoding;
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bytesPerFrame =
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Util.isEncodingLinearPcm(encoding)
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? Util.getPcmFrameSize(encoding, channelCount)
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: Format.NO_VALUE;
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}
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@Override
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public String toString() {
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return "AudioFormat["
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+ "sampleRate="
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+ sampleRate
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+ ", channelCount="
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+ channelCount
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+ ", encoding="
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+ encoding
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+ ']';
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}
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}
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/** Exception thrown when a processor can't be configured for a given input audio format. */
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final class UnhandledAudioFormatException extends Exception {
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public UnhandledAudioFormatException(AudioFormat inputAudioFormat) {
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super("Unhandled format: " + inputAudioFormat);
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}
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}
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/** An empty, direct {@link ByteBuffer}. */
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ByteBuffer EMPTY_BUFFER = ByteBuffer.allocateDirect(0).order(ByteOrder.nativeOrder());
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/**
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* Configures the processor to process input audio with the specified format. After calling this
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* method, call {@link #isActive()} to determine whether the audio processor is active. Returns
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* the configured output audio format if this instance is active.
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*
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* <p>After calling this method, it is necessary to {@link #flush()} the processor to apply the
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* new configuration. Before applying the new configuration, it is safe to queue input and get
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* output in the old input/output formats. Call {@link #queueEndOfStream()} when no more input
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* will be supplied in the old input format.
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*
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* @param inputAudioFormat The format of audio that will be queued after the next call to {@link
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* #flush()}.
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* @return The configured output audio format if this instance is {@link #isActive() active}.
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* @throws UnhandledAudioFormatException Thrown if the specified format can't be handled as input.
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*/
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AudioFormat configure(AudioFormat inputAudioFormat) throws UnhandledAudioFormatException;
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/** Returns whether the processor is configured and will process input buffers. */
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boolean isActive();
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/**
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* Queues audio data between the position and limit of the input {@code buffer} for processing.
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* {@code buffer} must be a direct byte buffer with native byte order. Its contents are treated as
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* read-only. Its position will be advanced by the number of bytes consumed (which may be zero).
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* The caller retains ownership of the provided buffer. Calling this method invalidates any
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* previous buffer returned by {@link #getOutput()}.
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*
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* @param buffer The input buffer to process.
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*/
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void queueInput(ByteBuffer buffer);
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/**
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* Queues an end of stream signal. After this method has been called,
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* {@link #queueInput(ByteBuffer)} may not be called until after the next call to
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* {@link #flush()}. Calling {@link #getOutput()} will return any remaining output data. Multiple
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* calls may be required to read all of the remaining output data. {@link #isEnded()} will return
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* {@code true} once all remaining output data has been read.
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*/
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void queueEndOfStream();
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/**
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* Returns a buffer containing processed output data between its position and limit. The buffer
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* will always be a direct byte buffer with native byte order. Calling this method invalidates any
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* previously returned buffer. The buffer will be empty if no output is available.
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*
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* @return A buffer containing processed output data between its position and limit.
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*/
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ByteBuffer getOutput();
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/**
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* Returns whether this processor will return no more output from {@link #getOutput()} until it
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* has been {@link #flush()}ed and more input has been queued.
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*/
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boolean isEnded();
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/**
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* Clears any buffered data and pending output. If the audio processor is active, also prepares
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* the audio processor to receive a new stream of input in the last configured (pending) format.
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*/
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void flush();
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/** Resets the processor to its unconfigured state, releasing any resources. */
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void reset();
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}
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