/*
* Copyright (C) 2016 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 androidx.media3.exoplayer;
import androidx.media3.common.PlaybackParameters;
import androidx.media3.common.util.Clock;
import androidx.media3.common.util.UnstableApi;
import androidx.media3.common.util.Util;
/**
* A {@link MediaClock} whose position advances with real time based on the playback parameters when
* started.
*/
@UnstableApi
public final class StandaloneMediaClock implements MediaClock {
private final Clock clock;
private boolean started;
private long baseUs;
private long baseElapsedMs;
private PlaybackParameters playbackParameters;
/**
* Creates a new standalone media clock using the given {@link Clock} implementation.
*
* @param clock A {@link Clock}.
*/
public StandaloneMediaClock(Clock clock) {
this.clock = clock;
playbackParameters = PlaybackParameters.DEFAULT;
}
/** Starts the clock. Does nothing if the clock is already started. */
public void start() {
if (!started) {
baseElapsedMs = clock.elapsedRealtime();
started = true;
}
}
/** Stops the clock. Does nothing if the clock is already stopped. */
public void stop() {
if (started) {
resetPosition(getPositionUs());
started = false;
}
}
/**
* Resets the clock's position.
*
* @param positionUs The position to set in microseconds.
*/
public void resetPosition(long positionUs) {
baseUs = positionUs;
if (started) {
baseElapsedMs = clock.elapsedRealtime();
}
}
@Override
public long getPositionUs() {
long positionUs = baseUs;
if (started) {
long elapsedSinceBaseMs = clock.elapsedRealtime() - baseElapsedMs;
if (playbackParameters.speed == 1f) {
positionUs += Util.msToUs(elapsedSinceBaseMs);
} else {
// Add the media time in microseconds that will elapse in elapsedSinceBaseMs milliseconds of
// wallclock time
positionUs += playbackParameters.getMediaTimeUsForPlayoutTimeMs(elapsedSinceBaseMs);
}
}
return positionUs;
}
@Override
public void setPlaybackParameters(PlaybackParameters playbackParameters) {
// Store the current position as the new base, in case the playback speed has changed.
if (started) {
resetPosition(getPositionUs());
}
this.playbackParameters = playbackParameters;
}
@Override
public PlaybackParameters getPlaybackParameters() {
return playbackParameters;
}
}