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/*
* Copyright (C) 2015 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 android.media;
import android.annotation.IntDef;
import android.annotation.NonNull;
import android.annotation.Nullable;
import android.media.AudioTrack;
import android.media.PlaybackParams;
import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import android.util.Log;
import android.view.Surface;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.nio.ByteBuffer;
import java.util.concurrent.TimeUnit;
import java.util.LinkedList;
import java.util.List;
/**
* MediaSync class can be used to synchronously playback audio and video streams.
* It can be used to play audio-only or video-only stream, too.
*
* MediaSync is generally used like this:
*
* MediaSync sync = new MediaSync();
* sync.setSurface(surface);
* Surface inputSurface = sync.createInputSurface();
* ...
* // MediaCodec videoDecoder = ...;
* videoDecoder.configure(format, inputSurface, ...);
* ...
* sync.setAudioTrack(audioTrack);
* sync.setCallback(new MediaSync.Callback() {
* {@literal @Override}
* public void onAudioBufferConsumed(MediaSync sync, ByteBuffer audioBuffer, int bufferId) {
* ...
* }
* }, null);
* // This needs to be done since sync is paused on creation.
* sync.setPlaybackParams(new PlaybackParams().setSpeed(1.f));
*
* for (;;) {
* ...
* // send video frames to surface for rendering, e.g., call
* // videoDecoder.releaseOutputBuffer(videoOutputBufferIx, videoPresentationTimeNs);
* // More details are available as below.
* ...
* sync.queueAudio(audioByteBuffer, bufferId, audioPresentationTimeUs); // non-blocking.
* // The audioByteBuffer and bufferId will be returned via callback.
* // More details are available as below.
* ...
* ...
* }
* sync.setPlaybackParams(new PlaybackParams().setSpeed(0.f));
* sync.release();
* sync = null;
*
* // The following code snippet illustrates how video/audio raw frames are created by
* // MediaCodec's, how they are fed to MediaSync and how they are returned by MediaSync.
* // This is the callback from MediaCodec.
* onOutputBufferAvailable(MediaCodec codec, int bufferId, BufferInfo info) {
* // ...
* if (codec == videoDecoder) {
* // surface timestamp must contain media presentation time in nanoseconds.
* codec.releaseOutputBuffer(bufferId, 1000 * info.presentationTime);
* } else {
* ByteBuffer audioByteBuffer = codec.getOutputBuffer(bufferId);
* sync.queueAudio(audioByteBuffer, bufferId, info.presentationTime);
* }
* // ...
* }
*
* // This is the callback from MediaSync.
* onAudioBufferConsumed(MediaSync sync, ByteBuffer buffer, int bufferId) {
* // ...
* audioDecoder.releaseBuffer(bufferId, false);
* // ...
* }
*
*
*
* The client needs to configure corresponding sink by setting the Surface and/or AudioTrack
* based on the stream type it will play.
*
* For video, the client needs to call {@link #createInputSurface} to obtain a surface on
* which it will render video frames.
*
* For audio, the client needs to set up audio track correctly, e.g., using {@link
* AudioTrack#MODE_STREAM}. The audio buffers are sent to MediaSync directly via {@link
* #queueAudio}, and are returned to the client via {@link Callback#onAudioBufferConsumed}
* asynchronously. The client should not modify an audio buffer till it's returned.
*
* The client can optionally pre-fill audio/video buffers by setting playback rate to 0.0,
* and then feed audio/video buffers to corresponding components. This can reduce possible
* initial underrun.
*
*/
public final class MediaSync {
/**
* MediaSync callback interface. Used to notify the user asynchronously
* of various MediaSync events.
*/
public static abstract class Callback {
/**
* Called when returning an audio buffer which has been consumed.
*
* @param sync The MediaSync object.
* @param audioBuffer The returned audio buffer.
* @param bufferId The ID associated with audioBuffer as passed into
* {@link MediaSync#queueAudio}.
*/
public abstract void onAudioBufferConsumed(
@NonNull MediaSync sync, @NonNull ByteBuffer audioBuffer, int bufferId);
}
/** Audio track failed.
* @see android.media.MediaSync.OnErrorListener
*/
public static final int MEDIASYNC_ERROR_AUDIOTRACK_FAIL = 1;
/** The surface failed to handle video buffers.
* @see android.media.MediaSync.OnErrorListener
*/
public static final int MEDIASYNC_ERROR_SURFACE_FAIL = 2;
/**
* Interface definition of a callback to be invoked when there
* has been an error during an asynchronous operation (other errors
* will throw exceptions at method call time).
*/
public interface OnErrorListener {
/**
* Called to indicate an error.
*
* @param sync The MediaSync the error pertains to
* @param what The type of error that has occurred:
*
* - {@link #MEDIASYNC_ERROR_AUDIOTRACK_FAIL}
*
- {@link #MEDIASYNC_ERROR_SURFACE_FAIL}
*
* @param extra an extra code, specific to the error. Typically
* implementation dependent.
*/
void onError(@NonNull MediaSync sync, int what, int extra);
}
private static final String TAG = "MediaSync";
private static final int EVENT_CALLBACK = 1;
private static final int EVENT_SET_CALLBACK = 2;
private static final int CB_RETURN_AUDIO_BUFFER = 1;
private static class AudioBuffer {
public ByteBuffer mByteBuffer;
public int mBufferIndex;
long mPresentationTimeUs;
public AudioBuffer(@NonNull ByteBuffer byteBuffer, int bufferId,
long presentationTimeUs) {
mByteBuffer = byteBuffer;
mBufferIndex = bufferId;
mPresentationTimeUs = presentationTimeUs;
}
}
private final Object mCallbackLock = new Object();
private Handler mCallbackHandler = null;
private MediaSync.Callback mCallback = null;
private final Object mOnErrorListenerLock = new Object();
private Handler mOnErrorListenerHandler = null;
private MediaSync.OnErrorListener mOnErrorListener = null;
private Thread mAudioThread = null;
// Created on mAudioThread when mAudioThread is started. When used on user thread, they should
// be guarded by checking mAudioThread.
private Handler mAudioHandler = null;
private Looper mAudioLooper = null;
private final Object mAudioLock = new Object();
private AudioTrack mAudioTrack = null;
private List mAudioBuffers = new LinkedList();
// this is only used for paused/running decisions, so it is not affected by clock drift
private float mPlaybackRate = 0.0f;
private long mNativeContext;
/**
* Class constructor. On creation, MediaSync is paused, i.e., playback rate is 0.0f.
*/
public MediaSync() {
native_setup();
}
private native final void native_setup();
@Override
protected void finalize() {
native_finalize();
}
private native final void native_finalize();
/**
* Make sure you call this when you're done to free up any opened
* component instance instead of relying on the garbage collector
* to do this for you at some point in the future.
*/
public final void release() {
returnAudioBuffers();
if (mAudioThread != null) {
if (mAudioLooper != null) {
mAudioLooper.quit();
}
}
setCallback(null, null);
native_release();
}
private native final void native_release();
/**
* Sets an asynchronous callback for actionable MediaSync events.
*
* This method can be called multiple times to update a previously set callback. If the
* handler is changed, undelivered notifications scheduled for the old handler may be dropped.
*
* Do not call this inside callback.
*
* @param cb The callback that will run. Use {@code null} to stop receiving callbacks.
* @param handler The Handler that will run the callback. Use {@code null} to use MediaSync's
* internal handler if it exists.
*/
public void setCallback(@Nullable /* MediaSync. */ Callback cb, @Nullable Handler handler) {
synchronized(mCallbackLock) {
if (handler != null) {
mCallbackHandler = handler;
} else {
Looper looper;
if ((looper = Looper.myLooper()) == null) {
looper = Looper.getMainLooper();
}
if (looper == null) {
mCallbackHandler = null;
} else {
mCallbackHandler = new Handler(looper);
}
}
mCallback = cb;
}
}
/**
* Sets an asynchronous callback for error events.
*
* This method can be called multiple times to update a previously set listener. If the
* handler is changed, undelivered notifications scheduled for the old handler may be dropped.
*
* Do not call this inside callback.
*
* @param listener The callback that will run. Use {@code null} to stop receiving callbacks.
* @param handler The Handler that will run the callback. Use {@code null} to use MediaSync's
* internal handler if it exists.
*/
public void setOnErrorListener(@Nullable /* MediaSync. */ OnErrorListener listener,
@Nullable Handler handler) {
synchronized(mOnErrorListenerLock) {
if (handler != null) {
mOnErrorListenerHandler = handler;
} else {
Looper looper;
if ((looper = Looper.myLooper()) == null) {
looper = Looper.getMainLooper();
}
if (looper == null) {
mOnErrorListenerHandler = null;
} else {
mOnErrorListenerHandler = new Handler(looper);
}
}
mOnErrorListener = listener;
}
}
/**
* Sets the output surface for MediaSync.
*
* Currently, this is only supported in the Initialized state.
*
* @param surface Specify a surface on which to render the video data.
* @throws IllegalArgumentException if the surface has been released, is invalid,
* or can not be connected.
* @throws IllegalStateException if setting the surface is not supported, e.g.
* not in the Initialized state, or another surface has already been set.
*/
public void setSurface(@Nullable Surface surface) {
native_setSurface(surface);
}
private native final void native_setSurface(@Nullable Surface surface);
/**
* Sets the audio track for MediaSync.
*
* Currently, this is only supported in the Initialized state.
*
* @param audioTrack Specify an AudioTrack through which to render the audio data.
* @throws IllegalArgumentException if the audioTrack has been released, or is invalid.
* @throws IllegalStateException if setting the audio track is not supported, e.g.
* not in the Initialized state, or another audio track has already been set.
*/
public void setAudioTrack(@Nullable AudioTrack audioTrack) {
native_setAudioTrack(audioTrack);
mAudioTrack = audioTrack;
if (audioTrack != null && mAudioThread == null) {
createAudioThread();
}
}
private native final void native_setAudioTrack(@Nullable AudioTrack audioTrack);
/**
* Requests a Surface to use as the input. This may only be called after
* {@link #setSurface}.
*
* The application is responsible for calling release() on the Surface when
* done.
* @throws IllegalStateException if not set, or another input surface has
* already been created.
*/
@NonNull
public native final Surface createInputSurface();
/**
* Sets playback rate using {@link PlaybackParams}.
*
* When using MediaSync with {@link AudioTrack}, set playback params using this
* call instead of calling it directly on the track, so that the sync is aware of
* the params change.
*
* This call also works if there is no audio track.
*
* @param params the playback params to use. {@link PlaybackParams#getSpeed
* Speed} is the ratio between desired playback rate and normal one. 1.0 means
* normal playback speed. 0.0 means pause. Value larger than 1.0 means faster playback,
* while value between 0.0 and 1.0 for slower playback. Note: the normal rate
* does not change as a result of this call. To restore the original rate at any time,
* use speed of 1.0.
*
* @throws IllegalStateException if the internal sync engine or the audio track has not
* been initialized.
* @throws IllegalArgumentException if the params are not supported.
*/
public void setPlaybackParams(@NonNull PlaybackParams params) {
synchronized(mAudioLock) {
mPlaybackRate = native_setPlaybackParams(params);;
}
if (mPlaybackRate != 0.0 && mAudioThread != null) {
postRenderAudio(0);
}
}
/**
* Gets the playback rate using {@link PlaybackParams}.
*
* @return the playback rate being used.
*
* @throws IllegalStateException if the internal sync engine or the audio track has not
* been initialized.
*/
@NonNull
public native PlaybackParams getPlaybackParams();
private native float native_setPlaybackParams(@NonNull PlaybackParams params);
/**
* Sets A/V sync mode.
*
* @param params the A/V sync params to apply
*
* @throws IllegalStateException if the internal player engine has not been
* initialized.
* @throws IllegalArgumentException if params are not supported.
*/
public void setSyncParams(@NonNull SyncParams params) {
synchronized(mAudioLock) {
mPlaybackRate = native_setSyncParams(params);;
}
if (mPlaybackRate != 0.0 && mAudioThread != null) {
postRenderAudio(0);
}
}
private native float native_setSyncParams(@NonNull SyncParams params);
/**
* Gets the A/V sync mode.
*
* @return the A/V sync params
*
* @throws IllegalStateException if the internal player engine has not been
* initialized.
*/
@NonNull
public native SyncParams getSyncParams();
/**
* Flushes all buffers from the sync object.
*
* All pending unprocessed audio and video buffers are discarded. If an audio track was
* configured, it is flushed and stopped. If a video output surface was configured, the
* last frame queued to it is left on the frame. Queue a blank video frame to clear the
* surface,
*
* No callbacks are received for the flushed buffers.
*
* @throws IllegalStateException if the internal player engine has not been
* initialized.
*/
public void flush() {
synchronized(mAudioLock) {
mAudioBuffers.clear();
mCallbackHandler.removeCallbacksAndMessages(null);
}
if (mAudioTrack != null) {
mAudioTrack.pause();
mAudioTrack.flush();
// Call stop() to signal to the AudioSink to completely fill the
// internal buffer before resuming playback.
mAudioTrack.stop();
}
native_flush();
}
private native final void native_flush();
/**
* Get current playback position.
*
* The MediaTimestamp represents how the media time correlates to the system time in
* a linear fashion using an anchor and a clock rate. During regular playback, the media
* time moves fairly constantly (though the anchor frame may be rebased to a current
* system time, the linear correlation stays steady). Therefore, this method does not
* need to be called often.
*
* To help users get current playback position, this method always anchors the timestamp
* to the current {@link System#nanoTime system time}, so
* {@link MediaTimestamp#getAnchorMediaTimeUs} can be used as current playback position.
*
* @return a MediaTimestamp object if a timestamp is available, or {@code null} if no timestamp
* is available, e.g. because the media player has not been initialized.
*
* @see MediaTimestamp
*/
@Nullable
public MediaTimestamp getTimestamp()
{
try {
// TODO: create the timestamp in native
MediaTimestamp timestamp = new MediaTimestamp();
if (native_getTimestamp(timestamp)) {
return timestamp;
} else {
return null;
}
} catch (IllegalStateException e) {
return null;
}
}
private native final boolean native_getTimestamp(@NonNull MediaTimestamp timestamp);
/**
* Queues the audio data asynchronously for playback (AudioTrack must be in streaming mode).
* If the audio track was flushed as a result of {@link #flush}, it will be restarted.
* @param audioData the buffer that holds the data to play. This buffer will be returned
* to the client via registered callback.
* @param bufferId an integer used to identify audioData. It will be returned to
* the client along with audioData. This helps applications to keep track of audioData,
* e.g., it can be used to store the output buffer index used by the audio codec.
* @param presentationTimeUs the presentation timestamp in microseconds for the first frame
* in the buffer.
* @throws IllegalStateException if audio track is not set or internal configureation
* has not been done correctly.
*/
public void queueAudio(
@NonNull ByteBuffer audioData, int bufferId, long presentationTimeUs) {
if (mAudioTrack == null || mAudioThread == null) {
throw new IllegalStateException(
"AudioTrack is NOT set or audio thread is not created");
}
synchronized(mAudioLock) {
mAudioBuffers.add(new AudioBuffer(audioData, bufferId, presentationTimeUs));
}
if (mPlaybackRate != 0.0) {
postRenderAudio(0);
}
}
// When called on user thread, make sure to check mAudioThread != null.
private void postRenderAudio(long delayMillis) {
mAudioHandler.postDelayed(new Runnable() {
public void run() {
synchronized(mAudioLock) {
if (mPlaybackRate == 0.0) {
return;
}
if (mAudioBuffers.isEmpty()) {
return;
}
AudioBuffer audioBuffer = mAudioBuffers.get(0);
int size = audioBuffer.mByteBuffer.remaining();
// restart audio track after flush
if (size > 0 && mAudioTrack.getPlayState() != AudioTrack.PLAYSTATE_PLAYING) {
try {
mAudioTrack.play();
} catch (IllegalStateException e) {
Log.w(TAG, "could not start audio track");
}
}
int sizeWritten = mAudioTrack.write(
audioBuffer.mByteBuffer,
size,
AudioTrack.WRITE_NON_BLOCKING);
if (sizeWritten > 0) {
if (audioBuffer.mPresentationTimeUs != -1) {
native_updateQueuedAudioData(
size, audioBuffer.mPresentationTimeUs);
audioBuffer.mPresentationTimeUs = -1;
}
if (sizeWritten == size) {
postReturnByteBuffer(audioBuffer);
mAudioBuffers.remove(0);
if (!mAudioBuffers.isEmpty()) {
postRenderAudio(0);
}
return;
}
}
long pendingTimeMs = TimeUnit.MICROSECONDS.toMillis(
native_getPlayTimeForPendingAudioFrames());
postRenderAudio(pendingTimeMs / 2);
}
}
}, delayMillis);
}
private native final void native_updateQueuedAudioData(
int sizeInBytes, long presentationTimeUs);
private native final long native_getPlayTimeForPendingAudioFrames();
private final void postReturnByteBuffer(@NonNull final AudioBuffer audioBuffer) {
synchronized(mCallbackLock) {
if (mCallbackHandler != null) {
final MediaSync sync = this;
mCallbackHandler.post(new Runnable() {
public void run() {
Callback callback;
synchronized(mCallbackLock) {
callback = mCallback;
if (mCallbackHandler == null
|| mCallbackHandler.getLooper().getThread()
!= Thread.currentThread()) {
// callback handler has been changed.
return;
}
}
if (callback != null) {
callback.onAudioBufferConsumed(sync, audioBuffer.mByteBuffer,
audioBuffer.mBufferIndex);
}
}
});
}
}
}
private final void returnAudioBuffers() {
synchronized(mAudioLock) {
for (AudioBuffer audioBuffer: mAudioBuffers) {
postReturnByteBuffer(audioBuffer);
}
mAudioBuffers.clear();
}
}
private void createAudioThread() {
mAudioThread = new Thread() {
@Override
public void run() {
Looper.prepare();
synchronized(mAudioLock) {
mAudioLooper = Looper.myLooper();
mAudioHandler = new Handler();
mAudioLock.notify();
}
Looper.loop();
}
};
mAudioThread.start();
synchronized(mAudioLock) {
try {
mAudioLock.wait();
} catch(InterruptedException e) {
}
}
}
static {
System.loadLibrary("media_jni");
native_init();
}
private static native final void native_init();
}