/*
* 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.C;
import androidx.media3.common.MediaPeriodId;
import androidx.media3.common.Timeline;
import androidx.media3.common.TrackGroup;
import androidx.media3.common.util.UnstableApi;
import androidx.media3.exoplayer.source.MediaPeriod;
import androidx.media3.exoplayer.source.TrackGroupArray;
import androidx.media3.exoplayer.trackselection.ExoTrackSelection;
import androidx.media3.exoplayer.upstream.Allocator;
/** Controls buffering of media. */
@UnstableApi
public interface LoadControl {
/**
* @deprecated Used as a placeholder when MediaPeriodId is unknown. Only used when the deprecated
* methods {@link #onTracksSelected(Renderer[], TrackGroupArray, ExoTrackSelection[])} or
* {@link #shouldStartPlayback(long, float, boolean, long)} are called.
*/
@Deprecated
MediaPeriodId EMPTY_MEDIA_PERIOD_ID = new MediaPeriodId(/* periodUid= */ new Object());
/** Called by the player when prepared with a new source. */
void onPrepared();
/**
* Called by the player when a track selection occurs.
*
* @param timeline The current {@link Timeline} in ExoPlayer. Can be {@link Timeline#EMPTY} only
* when the deprecated {@link #onTracksSelected(Renderer[], TrackGroupArray,
* ExoTrackSelection[])} was called.
* @param mediaPeriodId Identifies (in the current timeline) the {@link MediaPeriod} for which the
* selection was made. Will be {@link #EMPTY_MEDIA_PERIOD_ID} when {@code timeline} is empty.
* @param renderers The renderers.
* @param trackGroups The {@link TrackGroup}s from which the selection was made.
* @param trackSelections The track selections that were made.
*/
@SuppressWarnings("deprecation") // Calling deprecated version of this method.
default void onTracksSelected(
Timeline timeline,
MediaPeriodId mediaPeriodId,
Renderer[] renderers,
TrackGroupArray trackGroups,
ExoTrackSelection[] trackSelections) {
onTracksSelected(renderers, trackGroups, trackSelections);
}
/**
* @deprecated Implement {@link #onTracksSelected(Timeline, MediaPeriodId, Renderer[],
* TrackGroupArray, ExoTrackSelection[])} instead.
*/
@Deprecated
default void onTracksSelected(
Renderer[] renderers, TrackGroupArray trackGroups, ExoTrackSelection[] trackSelections) {
onTracksSelected(
Timeline.EMPTY, EMPTY_MEDIA_PERIOD_ID, renderers, trackGroups, trackSelections);
}
/** Called by the player when stopped. */
void onStopped();
/** Called by the player when released. */
void onReleased();
/** Returns the {@link Allocator} that should be used to obtain media buffer allocations. */
Allocator getAllocator();
/**
* Returns the duration of media to retain in the buffer prior to the current playback position,
* for fast backward seeking.
*
* <p>Note: If {@link #retainBackBufferFromKeyframe()} is false then seeking in the back-buffer
* will only be fast if the back-buffer contains a keyframe prior to the seek position.
*
* <p>Note: Implementations should return a single value. Dynamic changes to the back-buffer are
* not currently supported.
*
* @return The duration of media to retain in the buffer prior to the current playback position,
* in microseconds.
*/
long getBackBufferDurationUs();
/**
* Returns whether media should be retained from the keyframe before the current playback position
* minus {@link #getBackBufferDurationUs()}, rather than any sample before or at that position.
*
* <p>Warning: Returning true will cause the back-buffer size to depend on the spacing of
* keyframes in the media being played. Returning true is not recommended unless you control the
* media and are comfortable with the back-buffer size exceeding {@link
* #getBackBufferDurationUs()} by as much as the maximum duration between adjacent keyframes in
* the media.
*
* <p>Note: Implementations should return a single value. Dynamic changes to the back-buffer are
* not currently supported.
*
* @return Whether media should be retained from the keyframe before the current playback position
* minus {@link #getBackBufferDurationUs()}, rather than any sample before or at that
* position.
*/
boolean retainBackBufferFromKeyframe();
/**
* Called by the player to determine whether it should continue to load the source. If this method
* returns true, the {@link MediaPeriod} identified in the most recent {@link #onTracksSelected}
* call will continue being loaded.
*
* @param playbackPositionUs The current playback position in microseconds, relative to the start
* of the {@link Timeline.Period period} that will continue to be loaded if this method
* returns {@code true}. If playback of this period has not yet started, the value will be
* negative and equal in magnitude to the duration of any media in previous periods still to
* be played.
* @param bufferedDurationUs The duration of media that's currently buffered.
* @param playbackSpeed The current factor by which playback is sped up.
* @return Whether the loading should continue.
*/
boolean shouldContinueLoading(
long playbackPositionUs, long bufferedDurationUs, float playbackSpeed);
/**
* Called repeatedly by the player when it's loading the source, has yet to start playback, and
* has the minimum amount of data necessary for playback to be started. The value returned
* determines whether playback is actually started. The load control may opt to return {@code
* false} until some condition has been met (e.g. a certain amount of media is buffered).
*
* @param timeline The current {@link Timeline} in ExoPlayer. Can be {@link Timeline#EMPTY} only
* when the deprecated {@link #shouldStartPlayback(long, float, boolean, long)} was called.
* @param mediaPeriodId Identifies (in the current timeline) the {@link MediaPeriod} for which
* playback will start. Will be {@link #EMPTY_MEDIA_PERIOD_ID} when {@code timeline} is empty.
* @param bufferedDurationUs The duration of media that's currently buffered.
* @param playbackSpeed The current factor by which playback is sped up.
* @param rebuffering Whether the player is rebuffering. A rebuffer is defined to be caused by
* buffer depletion rather than a user action. Hence this parameter is false during initial
* buffering and when buffering as a result of a seek operation.
* @param targetLiveOffsetUs The desired playback position offset to the live edge in
* microseconds, or {@link C#TIME_UNSET} if the media is not a live stream or no offset is
* configured.
* @return Whether playback should be allowed to start or resume.
*/
@SuppressWarnings("deprecation") // Calling deprecated version of this method.
default boolean shouldStartPlayback(
Timeline timeline,
MediaPeriodId mediaPeriodId,
long bufferedDurationUs,
float playbackSpeed,
boolean rebuffering,
long targetLiveOffsetUs) {
return shouldStartPlayback(bufferedDurationUs, playbackSpeed, rebuffering, targetLiveOffsetUs);
}
/**
* @deprecated Implement {@link #shouldStartPlayback(Timeline, MediaPeriodId, long, float,
* boolean, long)} instead.
*/
@Deprecated
default boolean shouldStartPlayback(
long bufferedDurationUs, float playbackSpeed, boolean rebuffering, long targetLiveOffsetUs) {
return shouldStartPlayback(
Timeline.EMPTY,
EMPTY_MEDIA_PERIOD_ID,
bufferedDurationUs,
playbackSpeed,
rebuffering,
targetLiveOffsetUs);
}
}