/*
* Copyright 2023 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
*
* https://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.extractor.text;
import android.util.SparseArray;
import androidx.media3.common.C;
import androidx.media3.common.Format;
import androidx.media3.common.MimeTypes;
import androidx.media3.common.util.UnstableApi;
import androidx.media3.extractor.ExtractorOutput;
import androidx.media3.extractor.SeekMap;
import androidx.media3.extractor.TrackOutput;
/**
* A wrapping {@link ExtractorOutput} that transcodes {@linkplain C#TRACK_TYPE_TEXT text samples}
* from supported subtitle formats to {@link MimeTypes#APPLICATION_MEDIA3_CUES}.
*
* <p>The resulting {@link MimeTypes#APPLICATION_MEDIA3_CUES} samples are emitted to the underlying
* {@link TrackOutput}.
*
* <p>For non-text tracks (i.e. where {@link C.TrackType} is not {@code C.TRACK_TYPE_TEXT}), samples
* are passed through to the underlying {@link TrackOutput} without modification.
*
* <p>Support for subtitle formats is determined by {@link
* SubtitleParser.Factory#supportsFormat(Format)} on the {@link SubtitleParser.Factory} passed to
* the constructor of this class.
*/
@UnstableApi
public final class SubtitleTranscodingExtractorOutput implements ExtractorOutput {
private final ExtractorOutput delegate;
private final SubtitleParser.Factory subtitleParserFactory;
private final SparseArray<SubtitleTranscodingTrackOutput> textTrackOutputs;
public SubtitleTranscodingExtractorOutput(
ExtractorOutput delegate, SubtitleParser.Factory subtitleParserFactory) {
this.delegate = delegate;
this.subtitleParserFactory = subtitleParserFactory;
textTrackOutputs = new SparseArray<>();
}
public void resetSubtitleParsers() {
for (int i = 0; i < textTrackOutputs.size(); i++) {
textTrackOutputs.valueAt(i).resetSubtitleParser();
}
}
// ExtractorOutput implementation
@Override
public TrackOutput track(int id, @C.TrackType int type) {
if (type != C.TRACK_TYPE_TEXT) {
return delegate.track(id, type);
}
SubtitleTranscodingTrackOutput existingTrackOutput = textTrackOutputs.get(id);
if (existingTrackOutput != null) {
return existingTrackOutput;
}
SubtitleTranscodingTrackOutput trackOutput =
new SubtitleTranscodingTrackOutput(delegate.track(id, type), subtitleParserFactory);
textTrackOutputs.put(id, trackOutput);
return trackOutput;
}
@Override
public void endTracks() {
delegate.endTracks();
}
@Override
public void seekMap(SeekMap seekMap) {
delegate.seekMap(seekMap);
}
}