TrackGroup.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.common;
import static androidx.media3.common.util.Assertions.checkArgument;
import static java.lang.annotation.ElementType.TYPE_USE;
import android.os.Bundle;
import androidx.annotation.CheckResult;
import androidx.annotation.IntDef;
import androidx.annotation.Nullable;
import androidx.media3.common.util.BundleableUtil;
import androidx.media3.common.util.Log;
import androidx.media3.common.util.UnstableApi;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Lists;
import java.lang.annotation.Documented;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.util.Arrays;
import java.util.List;
/**
* An immutable group of tracks available within a media stream. All tracks in a group present the
* same content, but their formats may differ.
*
* <p>As an example of how tracks can be grouped, consider an adaptive playback where a main video
* feed is provided in five resolutions, and an alternative video feed (e.g., a different camera
* angle in a sports match) is provided in two resolutions. In this case there will be two video
* track groups, one corresponding to the main video feed containing five tracks, and a second for
* the alternative video feed containing two tracks.
*
* <p>Note that audio tracks whose languages differ are not grouped, because content in different
* languages is not considered to be the same. Conversely, audio tracks in the same language that
* only differ in properties such as bitrate, sampling rate, channel count and so on can be grouped.
* This also applies to text tracks.
*
* <p>Note also that this class only contains information derived from the media itself. Unlike
* {@link Tracks.Group}, it does not include runtime information such as the extent to which
* playback of each track is supported by the device, or which tracks are currently selected.
*/
public final class TrackGroup implements Bundleable {
private static final String TAG = "TrackGroup";
/** The number of tracks in the group. */
@UnstableApi public final int length;
/** An identifier for the track group. */
@UnstableApi public final String id;
/** The type of tracks in the group. */
@UnstableApi public final @C.TrackType int type;
private final Format[] formats;
// Lazily initialized hashcode.
private int hashCode;
/**
* Constructs a track group containing the provided {@code formats}.
*
* @param formats The list of {@link Format Formats}. Must not be empty.
*/
@UnstableApi
public TrackGroup(Format... formats) {
this(/* id= */ "", formats);
}
/**
* Constructs a track group with the provided {@code id} and {@code formats}.
*
* @param id The identifier of the track group. May be an empty string.
* @param formats The list of {@link Format Formats}. Must not be empty.
*/
@UnstableApi
public TrackGroup(String id, Format... formats) {
checkArgument(formats.length > 0);
this.id = id;
this.formats = formats;
this.length = formats.length;
@C.TrackType int type = MimeTypes.getTrackType(formats[0].sampleMimeType);
if (type == C.TRACK_TYPE_UNKNOWN) {
type = MimeTypes.getTrackType(formats[0].containerMimeType);
}
this.type = type;
verifyCorrectness();
}
/**
* Returns a copy of this track group with the specified {@code id}.
*
* @param id The identifier for the copy of the track group.
* @return The copied track group.
*/
@UnstableApi
@CheckResult
public TrackGroup copyWithId(String id) {
return new TrackGroup(id, formats);
}
/**
* Returns the format of the track at a given index.
*
* @param index The index of the track.
* @return The track's format.
*/
@UnstableApi
public Format getFormat(int index) {
return formats[index];
}
/**
* Returns the index of the track with the given format in the group. The format is located by
* identity so, for example, {@code group.indexOf(group.getFormat(index)) == index} even if
* multiple tracks have formats that contain the same values.
*
* @param format The format.
* @return The index of the track, or {@link C#INDEX_UNSET} if no such track exists.
*/
@SuppressWarnings("ReferenceEquality")
@UnstableApi
public int indexOf(Format format) {
for (int i = 0; i < formats.length; i++) {
if (format == formats[i]) {
return i;
}
}
return C.INDEX_UNSET;
}
@Override
public int hashCode() {
if (hashCode == 0) {
int result = 17;
result = 31 * result + id.hashCode();
result = 31 * result + Arrays.hashCode(formats);
hashCode = result;
}
return hashCode;
}
@Override
public boolean equals(@Nullable Object obj) {
if (this == obj) {
return true;
}
if (obj == null || getClass() != obj.getClass()) {
return false;
}
TrackGroup other = (TrackGroup) obj;
return id.equals(other.id) && Arrays.equals(formats, other.formats);
}
// Bundleable implementation.
@Documented
@Retention(RetentionPolicy.SOURCE)
@Target(TYPE_USE)
@IntDef({FIELD_FORMATS, FIELD_ID})
private @interface FieldNumber {}
private static final int FIELD_FORMATS = 0;
private static final int FIELD_ID = 1;
@UnstableApi
@Override
public Bundle toBundle() {
Bundle bundle = new Bundle();
bundle.putParcelableArrayList(
keyForField(FIELD_FORMATS), BundleableUtil.toBundleArrayList(Lists.newArrayList(formats)));
bundle.putString(keyForField(FIELD_ID), id);
return bundle;
}
/** Object that can restore {@code TrackGroup} from a {@link Bundle}. */
@UnstableApi
public static final Creator<TrackGroup> CREATOR =
bundle -> {
@Nullable
List<Bundle> formatBundles = bundle.getParcelableArrayList(keyForField(FIELD_FORMATS));
List<Format> formats =
formatBundles == null
? ImmutableList.of()
: BundleableUtil.fromBundleList(Format.CREATOR, formatBundles);
String id = bundle.getString(keyForField(FIELD_ID), /* defaultValue= */ "");
return new TrackGroup(id, formats.toArray(new Format[0]));
};
private static String keyForField(@FieldNumber int field) {
return Integer.toString(field, Character.MAX_RADIX);
}
private void verifyCorrectness() {
// TrackGroups should only contain tracks with exactly the same content (but in different
// qualities). We only log an error instead of throwing to not break backwards-compatibility for
// cases where malformed TrackGroups happen to work by chance (e.g. because adaptive selections
// are always disabled).
String language = normalizeLanguage(formats[0].language);
@C.RoleFlags int roleFlags = normalizeRoleFlags(formats[0].roleFlags);
for (int i = 1; i < formats.length; i++) {
if (!language.equals(normalizeLanguage(formats[i].language))) {
logErrorMessage(
/* mismatchField= */ "languages",
/* valueIndex0= */ formats[0].language,
/* otherValue=* */ formats[i].language,
/* otherIndex= */ i);
return;
}
if (roleFlags != normalizeRoleFlags(formats[i].roleFlags)) {
logErrorMessage(
/* mismatchField= */ "role flags",
/* valueIndex0= */ Integer.toBinaryString(formats[0].roleFlags),
/* otherValue=* */ Integer.toBinaryString(formats[i].roleFlags),
/* otherIndex= */ i);
return;
}
}
}
private static String normalizeLanguage(@Nullable String language) {
// Treat all variants of undetermined or unknown languages as compatible.
return language == null || language.equals(C.LANGUAGE_UNDETERMINED) ? "" : language;
}
private static @C.RoleFlags int normalizeRoleFlags(@C.RoleFlags int roleFlags) {
// Treat trick-play and non-trick-play formats as compatible.
return roleFlags | C.ROLE_FLAG_TRICK_PLAY;
}
private static void logErrorMessage(
String mismatchField,
@Nullable String valueIndex0,
@Nullable String otherValue,
int otherIndex) {
Log.e(
TAG,
"",
new IllegalStateException(
"Different "
+ mismatchField
+ " combined in one TrackGroup: '"
+ valueIndex0
+ "' (track 0) and '"
+ otherValue
+ "' (track "
+ otherIndex
+ ")"));
}
}