ChunkSource.java
/*
* 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.source.chunk;
import androidx.media3.common.util.UnstableApi;
import androidx.media3.exoplayer.SeekParameters;
import androidx.media3.exoplayer.upstream.LoadErrorHandlingPolicy;
import java.io.IOException;
import java.util.List;
/** A provider of {@link Chunk}s for a {@link ChunkSampleStream} to load. */
@UnstableApi
public interface ChunkSource {
/**
* Adjusts a seek position given the specified {@link SeekParameters}. Chunk boundaries are used
* as sync points.
*
* @param positionUs The seek position in microseconds.
* @param seekParameters Parameters that control how the seek is performed.
* @return The adjusted seek position, in microseconds.
*/
long getAdjustedSeekPositionUs(long positionUs, SeekParameters seekParameters);
/**
* If the source is currently having difficulty providing chunks, then this method throws the
* underlying error. Otherwise does nothing.
*
* @throws IOException The underlying error.
*/
void maybeThrowError() throws IOException;
/**
* Evaluates whether {@link MediaChunk}s should be removed from the back of the queue.
*
* <p>Removing {@link MediaChunk}s from the back of the queue can be useful if they could be
* replaced with chunks of a significantly higher quality (e.g. because the available bandwidth
* has substantially increased).
*
* <p>Will only be called if no {@link MediaChunk} in the queue is currently loading.
*
* @param playbackPositionUs The current playback position, in microseconds.
* @param queue The queue of buffered {@link MediaChunk}s.
* @return The preferred queue size.
*/
int getPreferredQueueSize(long playbackPositionUs, List<? extends MediaChunk> queue);
/**
* Returns whether an ongoing load of a chunk should be canceled.
*
* @param playbackPositionUs The current playback position, in microseconds.
* @param loadingChunk The currently loading {@link Chunk}.
* @param queue The queue of buffered {@link MediaChunk MediaChunks}.
* @return Whether the ongoing load of {@code loadingChunk} should be canceled.
*/
boolean shouldCancelLoad(
long playbackPositionUs, Chunk loadingChunk, List<? extends MediaChunk> queue);
/**
* Returns the next chunk to load.
*
* <p>If a chunk is available then {@link ChunkHolder#chunk} is set. If the end of the stream has
* been reached then {@link ChunkHolder#endOfStream} is set. If a chunk is not available but the
* end of the stream has not been reached, the {@link ChunkHolder} is not modified.
*
* @param playbackPositionUs The current playback position in microseconds. If playback of the
* period to which this chunk source belongs has not yet started, the value will be the
* starting position in the period minus the duration of any media in previous periods still
* to be played.
* @param loadPositionUs The current load position in microseconds. If {@code queue} is empty,
* this is the starting position from which chunks should be provided. Else it's equal to
* {@link MediaChunk#endTimeUs} of the last chunk in the {@code queue}.
* @param queue The queue of buffered {@link MediaChunk}s.
* @param out A holder to populate.
*/
void getNextChunk(
long playbackPositionUs,
long loadPositionUs,
List<? extends MediaChunk> queue,
ChunkHolder out);
/**
* Called when the {@link ChunkSampleStream} has finished loading a chunk obtained from this
* source.
*
* @param chunk The chunk whose load has been completed.
*/
void onChunkLoadCompleted(Chunk chunk);
/**
* Called when the {@link ChunkSampleStream} encounters an error loading a chunk obtained from
* this source.
*
* @param chunk The chunk whose load encountered the error.
* @param cancelable Whether the load can be canceled.
* @param loadErrorInfo The load error info.
* @param loadErrorHandlingPolicy The load error handling policy to customize the behaviour of
* handling the load error.
* @return Whether the load should be canceled so that a replacement chunk can be loaded instead.
* Must be {@code false} if {@code cancelable} is {@code false}. If {@code true}, {@link
* #getNextChunk(long, long, List, ChunkHolder)} will be called to obtain the replacement
* chunk.
*/
boolean onChunkLoadError(
Chunk chunk,
boolean cancelable,
LoadErrorHandlingPolicy.LoadErrorInfo loadErrorInfo,
LoadErrorHandlingPolicy loadErrorHandlingPolicy);
/** Releases any held resources. */
void release();
}