diff options
Diffstat (limited to 'tuner/src/com/android/tv/tuner/exoplayer/audio/AudioClock.java')
-rw-r--r-- | tuner/src/com/android/tv/tuner/exoplayer/audio/AudioClock.java | 94 |
1 files changed, 94 insertions, 0 deletions
diff --git a/tuner/src/com/android/tv/tuner/exoplayer/audio/AudioClock.java b/tuner/src/com/android/tv/tuner/exoplayer/audio/AudioClock.java new file mode 100644 index 00000000..13eabc3a --- /dev/null +++ b/tuner/src/com/android/tv/tuner/exoplayer/audio/AudioClock.java @@ -0,0 +1,94 @@ +/* + * 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 com.android.tv.tuner.exoplayer.audio; + +import android.os.SystemClock; +import com.android.tv.common.SoftPreconditions; + +/** + * Copy of {@link com.google.android.exoplayer.MediaClock}. + * + * <p>A simple clock for tracking the progression of media time. The clock can be started, stopped + * and its time can be set and retrieved. When started, this clock is based on {@link + * SystemClock#elapsedRealtime()}. + */ +/* package */ class AudioClock { + private boolean mStarted; + + /** The media time when the clock was last set or stopped. */ + private long mPositionUs; + + /** + * The difference between {@link SystemClock#elapsedRealtime()} and {@link #mPositionUs} when + * the clock was last set or mStarted. + */ + private long mDeltaUs; + + private float mPlaybackSpeed = 1.0f; + private long mDeltaUpdatedTimeUs; + + /** Starts the clock. Does nothing if the clock is already started. */ + public void start() { + if (!mStarted) { + mStarted = true; + mDeltaUs = elapsedRealtimeMinus(mPositionUs); + mDeltaUpdatedTimeUs = SystemClock.elapsedRealtime() * 1000; + } + } + + /** Stops the clock. Does nothing if the clock is already stopped. */ + public void stop() { + if (mStarted) { + mPositionUs = elapsedRealtimeMinus(mDeltaUs); + mStarted = false; + } + } + + /** @param timeUs The position to set in microseconds. */ + public void setPositionUs(long timeUs) { + this.mPositionUs = timeUs; + mDeltaUs = elapsedRealtimeMinus(timeUs); + mDeltaUpdatedTimeUs = SystemClock.elapsedRealtime() * 1000; + } + + /** @return The current position in microseconds. */ + public long getPositionUs() { + if (!mStarted) { + return mPositionUs; + } + if (mPlaybackSpeed != 1.0f) { + long elapsedTimeFromPlaybackSpeedChanged = + SystemClock.elapsedRealtime() * 1000 - mDeltaUpdatedTimeUs; + return elapsedRealtimeMinus(mDeltaUs) + + (long) ((mPlaybackSpeed - 1.0f) * elapsedTimeFromPlaybackSpeedChanged); + } else { + return elapsedRealtimeMinus(mDeltaUs); + } + } + + /** Sets playback speed. {@code speed} should be positive. */ + public void setPlaybackSpeed(float speed) { + SoftPreconditions.checkState(speed > 0); + mDeltaUs = elapsedRealtimeMinus(getPositionUs()); + mDeltaUpdatedTimeUs = SystemClock.elapsedRealtime() * 1000; + mPlaybackSpeed = speed; + } + + private long elapsedRealtimeMinus(long toSubtractUs) { + return SystemClock.elapsedRealtime() * 1000 - toSubtractUs; + } +} |