Merge pull request #12044 from TeamNewPipe/android-auto

Add support for Android Auto *(season 2)*

app/src/main/AndroidManifest.xml

@@ -64,6 +64,9 @@
             <intent-filter>
                 <action android:name="android.intent.action.MEDIA_BUTTON" />
             </intent-filter>
+            <intent-filter>
+                <action android:name="android.media.browse.MediaBrowserService"/>
+            </intent-filter>
         </service>
 
         <activity
@@ -424,5 +427,10 @@
         <meta-data
             android:name="com.samsung.android.multidisplay.keep_process_alive"
             android:value="true" />
+        <!-- Android Auto -->
+        <meta-data android:name="com.google.android.gms.car.application"
+            android:resource="@xml/automotive_app_desc" />
+        <meta-data android:name="com.google.android.gms.car.notification.SmallIcon"
+            android:resource="@mipmap/ic_launcher" />
     </application>
 </manifest>

app/src/main/java/org/schabi/newpipe/MainActivity.java

@@ -862,7 +862,8 @@ public class MainActivity extends AppCompatActivity {
                 @Override
                 public void onReceive(final Context context, final Intent intent) {
                     if (Objects.equals(intent.getAction(),
-                            VideoDetailFragment.ACTION_PLAYER_STARTED)) {
+                            VideoDetailFragment.ACTION_PLAYER_STARTED)
+                            && PlayerHolder.getInstance().isPlayerOpen()) {
                         openMiniPlayerIfMissing();
                         // At this point the player is added 100%, we can unregister. Other actions
                         // are useless since the fragment will not be removed after that.
@@ -874,6 +875,10 @@ public class MainActivity extends AppCompatActivity {
             final IntentFilter intentFilter = new IntentFilter();
             intentFilter.addAction(VideoDetailFragment.ACTION_PLAYER_STARTED);
             registerReceiver(broadcastReceiver, intentFilter);
+
+            // If the PlayerHolder is not bound yet, but the service is running, try to bind to it.
+            // Once the connection is established, the ACTION_PLAYER_STARTED will be sent.
+            PlayerHolder.getInstance().tryBindIfNeeded(this);
         }
     }
 

app/src/main/java/org/schabi/newpipe/database/history/model/StreamHistoryEntry.kt

@@ -3,6 +3,8 @@ package org.schabi.newpipe.database.history.model
 import androidx.room.ColumnInfo
 import androidx.room.Embedded
 import org.schabi.newpipe.database.stream.model.StreamEntity
+import org.schabi.newpipe.extractor.stream.StreamInfoItem
+import org.schabi.newpipe.util.image.ImageStrategy
 import java.time.OffsetDateTime
 
 data class StreamHistoryEntry(
@@ -27,4 +29,17 @@ data class StreamHistoryEntry(
         return this.streamEntity.uid == other.streamEntity.uid && streamId == other.streamId &&
             accessDate.isEqual(other.accessDate)
     }
+
+    fun toStreamInfoItem(): StreamInfoItem =
+        StreamInfoItem(
+            streamEntity.serviceId,
+            streamEntity.url,
+            streamEntity.title,
+            streamEntity.streamType,
+        ).apply {
+            duration = streamEntity.duration
+            uploaderName = streamEntity.uploader
+            uploaderUrl = streamEntity.uploaderUrl
+            thumbnails = ImageStrategy.dbUrlToImageList(streamEntity.thumbnailUrl)
+        }
 }

app/src/main/java/org/schabi/newpipe/database/playlist/PlaylistLocalItem.java

@@ -1,5 +1,7 @@
 package org.schabi.newpipe.database.playlist;
 
+import androidx.annotation.Nullable;
+
 import org.schabi.newpipe.database.LocalItem;
 
 public interface PlaylistLocalItem extends LocalItem {
@@ -10,4 +12,7 @@ public interface PlaylistLocalItem extends LocalItem {
     long getUid();
 
     void setDisplayIndex(long displayIndex);
+
+    @Nullable
+    String getThumbnailUrl();
 }

app/src/main/java/org/schabi/newpipe/database/playlist/PlaylistMetadataEntry.java

@@ -9,6 +9,8 @@ import static org.schabi.newpipe.database.playlist.model.PlaylistEntity.PLAYLIST
 import static org.schabi.newpipe.database.playlist.model.PlaylistEntity.PLAYLIST_THUMBNAIL_STREAM_ID;
 import static org.schabi.newpipe.database.playlist.model.PlaylistEntity.PLAYLIST_THUMBNAIL_URL;
 
+import androidx.annotation.Nullable;
+
 public class PlaylistMetadataEntry implements PlaylistLocalItem {
     public static final String PLAYLIST_STREAM_COUNT = "streamCount";
 
@@ -71,4 +73,10 @@ public class PlaylistMetadataEntry implements PlaylistLocalItem {
     public void setDisplayIndex(final long displayIndex) {
         this.displayIndex = displayIndex;
     }
+
+    @Nullable
+    @Override
+    public String getThumbnailUrl() {
+        return thumbnailUrl;
+    }
 }

app/src/main/java/org/schabi/newpipe/database/playlist/dao/PlaylistRemoteDAO.java

@@ -34,7 +34,7 @@ public interface PlaylistRemoteDAO extends BasicDAO<PlaylistRemoteEntity> {
 
     @Query("SELECT * FROM " + REMOTE_PLAYLIST_TABLE + " WHERE "
             + REMOTE_PLAYLIST_ID + " = :playlistId")
-    Flowable<List<PlaylistRemoteEntity>> getPlaylist(long playlistId);
+    Flowable<PlaylistRemoteEntity> getPlaylist(long playlistId);
 
     @Query("SELECT * FROM " + REMOTE_PLAYLIST_TABLE + " WHERE "
             + REMOTE_PLAYLIST_URL + " = :url AND " + REMOTE_PLAYLIST_SERVICE_ID + " = :serviceId")

app/src/main/java/org/schabi/newpipe/database/playlist/model/PlaylistRemoteEntity.java

@@ -2,6 +2,7 @@ package org.schabi.newpipe.database.playlist.model;
 
 import android.text.TextUtils;
 
+import androidx.annotation.Nullable;
 import androidx.room.ColumnInfo;
 import androidx.room.Entity;
 import androidx.room.Ignore;
@@ -134,6 +135,8 @@ public class PlaylistRemoteEntity implements PlaylistLocalItem {
         this.name = name;
     }
 
+    @Nullable
+    @Override
     public String getThumbnailUrl() {
         return thumbnailUrl;
     }

app/src/main/java/org/schabi/newpipe/fragments/detail/VideoDetailFragment.java

@@ -236,11 +236,14 @@ public final class VideoDetailFragment
     // Service management
     //////////////////////////////////////////////////////////////////////////*/
     @Override
-    public void onServiceConnected(final Player connectedPlayer,
-                                   final PlayerService connectedPlayerService,
-                                   final boolean playAfterConnect) {
-        player = connectedPlayer;
+    public void onServiceConnected(@NonNull final PlayerService connectedPlayerService) {
         playerService = connectedPlayerService;
+    }
+
+    @Override
+    public void onPlayerConnected(@NonNull final Player connectedPlayer,
+                                  final boolean playAfterConnect) {
+        player = connectedPlayer;
 
         // It will do nothing if the player is not in fullscreen mode
         hideSystemUiIfNeeded();
@@ -272,11 +275,18 @@ public final class VideoDetailFragment
         updateOverlayPlayQueueButtonVisibility();
     }
 
+    @Override
+    public void onPlayerDisconnected() {
+        player = null;
+        // the binding could be null at this point, if the app is finishing
+        if (binding != null) {
+            restoreDefaultBrightness();
+        }
+    }
+
     @Override
     public void onServiceDisconnected() {
         playerService = null;
-        player = null;
-        restoreDefaultBrightness();
     }
 
 
@@ -1848,13 +1858,16 @@ public final class VideoDetailFragment
 
     @Override
     public void onServiceStopped() {
-        setOverlayPlayPauseImage(false);
-        if (currentInfo != null) {
-            updateOverlayData(currentInfo.getName(),
-                    currentInfo.getUploaderName(),
-                    currentInfo.getThumbnails());
+        // the binding could be null at this point, if the app is finishing
+        if (binding != null) {
+            setOverlayPlayPauseImage(false);
+            if (currentInfo != null) {
+                updateOverlayData(currentInfo.getName(),
+                        currentInfo.getUploaderName(),
+                        currentInfo.getThumbnails());
+            }
+            updateOverlayPlayQueueButtonVisibility();
         }
-        updateOverlayPlayQueueButtonVisibility();
     }
 
     @Override

app/src/main/java/org/schabi/newpipe/ktx/Bundle.kt

@@ -7,3 +7,16 @@ import androidx.core.os.BundleCompat
 inline fun <reified T : Parcelable> Bundle.parcelableArrayList(key: String?): ArrayList<T>? {
     return BundleCompat.getParcelableArrayList(this, key, T::class.java)
 }
+
+fun Bundle?.toDebugString(): String {
+    if (this == null) {
+        return "null"
+    }
+    val string = StringBuilder("Bundle{")
+    for (key in this.keySet()) {
+        @Suppress("DEPRECATION") // we want this[key] to return items of any type
+        string.append(" ").append(key).append(" => ").append(this[key]).append(";")
+    }
+    string.append(" }")
+    return string.toString()
+}

app/src/main/java/org/schabi/newpipe/local/playlist/RemotePlaylistManager.java

@@ -26,6 +26,10 @@ public class RemotePlaylistManager {
         return playlistRemoteTable.getPlaylists().subscribeOn(Schedulers.io());
     }
 
+    public Flowable<PlaylistRemoteEntity> getPlaylist(final long playlistId) {
+        return playlistRemoteTable.getPlaylist(playlistId).subscribeOn(Schedulers.io());
+    }
+
     public Flowable<List<PlaylistRemoteEntity>> getPlaylist(final PlaylistInfo info) {
         return playlistRemoteTable.getPlaylist(info.getServiceId(), info.getUrl())
                 .subscribeOn(Schedulers.io());

app/src/main/java/org/schabi/newpipe/player/PlayQueueActivity.java

@@ -183,7 +183,10 @@ public final class PlayQueueActivity extends AppCompatActivity
     ////////////////////////////////////////////////////////////////////////////
 
     private void bind() {
+        // Note: this code should not really exist, and PlayerHolder should be used instead, but
+        // it will be rewritten when NewPlayer will replace the current player.
         final Intent bindIntent = new Intent(this, PlayerService.class);
+        bindIntent.setAction(PlayerService.BIND_PLAYER_HOLDER_ACTION);
         final boolean success = bindService(bindIntent, serviceConnection, BIND_AUTO_CREATE);
         if (!success) {
             unbindService(serviceConnection);
@@ -221,7 +224,7 @@ public final class PlayQueueActivity extends AppCompatActivity
                 Log.d(TAG, "Player service is connected");
 
                 if (service instanceof PlayerService.LocalBinder) {
-                    player = ((PlayerService.LocalBinder) service).getPlayer();
+                    player = ((PlayerService.LocalBinder) service).getService().getPlayer();
                 }
 
                 if (player == null || player.getPlayQueue() == null || player.exoPlayerIsNull()) {

app/src/main/java/org/schabi/newpipe/player/Player.java

@@ -55,6 +55,7 @@ import android.content.SharedPreferences;
 import android.graphics.Bitmap;
 import android.graphics.drawable.Drawable;
 import android.media.AudioManager;
+import android.support.v4.media.session.MediaSessionCompat;
 import android.util.Log;
 import android.view.LayoutInflater;
 
@@ -71,6 +72,7 @@ import com.google.android.exoplayer2.PlaybackParameters;
 import com.google.android.exoplayer2.Player.PositionInfo;
 import com.google.android.exoplayer2.Timeline;
 import com.google.android.exoplayer2.Tracks;
+import com.google.android.exoplayer2.ext.mediasession.MediaSessionConnector;
 import com.google.android.exoplayer2.source.MediaSource;
 import com.google.android.exoplayer2.text.CueGroup;
 import com.google.android.exoplayer2.trackselection.DefaultTrackSelector;
@@ -269,7 +271,16 @@ public final class Player implements PlaybackListener, Listener {
     //////////////////////////////////////////////////////////////////////////*/
     //region Constructor
 
-    public Player(@NonNull final PlayerService service) {
+    /**
+     * @param service the service this player resides in
+     * @param mediaSession used to build the {@link MediaSessionPlayerUi}, lives in the service and
+     *                     could possibly be reused with multiple player instances
+     * @param sessionConnector used to build the {@link MediaSessionPlayerUi}, lives in the service
+     *                         and could possibly be reused with multiple player instances
+     */
+    public Player(@NonNull final PlayerService service,
+                  @NonNull final MediaSessionCompat mediaSession,
+                  @NonNull final MediaSessionConnector sessionConnector) {
         this.service = service;
         context = service;
         prefs = PreferenceManager.getDefaultSharedPreferences(context);
@@ -302,7 +313,7 @@ public final class Player implements PlaybackListener, Listener {
         // notification ui in the UIs list, since the notification depends on the media session in
         // PlayerUi#initPlayer(), and UIs.call() guarantees UI order is preserved.
         UIs = new PlayerUiList(
-                new MediaSessionPlayerUi(this),
+                new MediaSessionPlayerUi(this, mediaSession, sessionConnector),
                 new NotificationPlayerUi(this)
         );
     }
@@ -646,7 +657,7 @@ public final class Player implements PlaybackListener, Listener {
             Log.d(TAG, "onPlaybackShutdown() called");
         }
         // destroys the service, which in turn will destroy the player
-        service.stopService();
+        service.destroyPlayerAndStopService();
     }
 
     public void smoothStopForImmediateReusing() {
@@ -718,7 +729,7 @@ public final class Player implements PlaybackListener, Listener {
                 pause();
                 break;
             case ACTION_CLOSE:
-                service.stopService();
+                service.destroyPlayerAndStopService();
                 break;
             case ACTION_PLAY_PAUSE:
                 playPause();
@@ -1375,6 +1386,19 @@ public final class Player implements PlaybackListener, Listener {
     public void onCues(@NonNull final CueGroup cueGroup) {
         UIs.call(playerUi -> playerUi.onCues(cueGroup.cues));
     }
+
+    /**
+     * To be called when the {@code PlaybackPreparer} set in the {@link MediaSessionConnector}
+     * receives an {@code onPrepare()} call. This function allows restoring the default behavior
+     * that would happen if there was no playback preparer set, i.e. to just call
+     * {@code player.prepare()}. You can find the default behavior in `onPlay()` inside the
+     * {@link MediaSessionConnector} file.
+     */
+    public void onPrepare() {
+        if (!exoPlayerIsNull()) {
+            simpleExoPlayer.prepare();
+        }
+    }
     //endregion
 
 

app/src/main/java/org/schabi/newpipe/player/PlayerService.java

@@ -21,75 +21,142 @@ package org.schabi.newpipe.player;
 
 import static org.schabi.newpipe.util.Localization.assureCorrectAppLanguage;
 
-import android.app.Service;
 import android.content.Context;
 import android.content.Intent;
 import android.os.Binder;
+import android.os.Bundle;
 import android.os.IBinder;
+import android.support.v4.media.MediaBrowserCompat;
+import android.support.v4.media.session.MediaSessionCompat;
 import android.util.Log;
 
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.core.app.ServiceCompat;
+import androidx.media.MediaBrowserServiceCompat;
+
+import com.google.android.exoplayer2.ext.mediasession.MediaSessionConnector;
+
+import org.schabi.newpipe.ktx.BundleKt;
+import org.schabi.newpipe.player.mediabrowser.MediaBrowserImpl;
+import org.schabi.newpipe.player.mediabrowser.MediaBrowserPlaybackPreparer;
 import org.schabi.newpipe.player.mediasession.MediaSessionPlayerUi;
 import org.schabi.newpipe.player.notification.NotificationPlayerUi;
 import org.schabi.newpipe.util.ThemeHelper;
 
 import java.lang.ref.WeakReference;
+import java.util.List;
+import java.util.function.Consumer;
 
 
 /**
  * One service for all players.
  */
-public final class PlayerService extends Service {
+public final class PlayerService extends MediaBrowserServiceCompat {
     private static final String TAG = PlayerService.class.getSimpleName();
     private static final boolean DEBUG = Player.DEBUG;
 
+    public static final String SHOULD_START_FOREGROUND_EXTRA = "should_start_foreground_extra";
+    public static final String BIND_PLAYER_HOLDER_ACTION = "bind_player_holder_action";
+
+    // These objects are used to cleanly separate the Service implementation (in this file) and the
+    // media browser and playback preparer implementations. At the moment the playback preparer is
+    // only used in conjunction with the media browser.
+    private MediaBrowserImpl mediaBrowserImpl;
+    private MediaBrowserPlaybackPreparer mediaBrowserPlaybackPreparer;
+
+    // these are instantiated in onCreate() as per
+    // https://developer.android.com/training/cars/media#browser_workflow
+    private MediaSessionCompat mediaSession;
+    private MediaSessionConnector sessionConnector;
+
+    @Nullable
     private Player player;
 
     private final IBinder mBinder = new PlayerService.LocalBinder(this);
 
+    /**
+     * The parameter taken by this {@link Consumer} can be null to indicate the player is being
+     * stopped.
+     */
+    @Nullable
+    private Consumer<Player> onPlayerStartedOrStopped = null;
 
-    /*//////////////////////////////////////////////////////////////////////////
-    // Service's LifeCycle
-    //////////////////////////////////////////////////////////////////////////*/
 
+    //region Service lifecycle
     @Override
     public void onCreate() {
+        super.onCreate();
+
         if (DEBUG) {
             Log.d(TAG, "onCreate() called");
         }
         assureCorrectAppLanguage(this);
         ThemeHelper.setTheme(this);
 
-        player = new Player(this);
-        /*
-        Create the player notification and start immediately the service in foreground,
-        otherwise if nothing is played or initializing the player and its components (especially
-        loading stream metadata) takes a lot of time, the app would crash on Android 8+ as the
-        service would never be put in the foreground while we said to the system we would do so
-         */
-        player.UIs().get(NotificationPlayerUi.class)
-                .ifPresent(NotificationPlayerUi::createNotificationAndStartForeground);
+        mediaBrowserImpl = new MediaBrowserImpl(this, this::notifyChildrenChanged);
+
+        // see https://developer.android.com/training/cars/media#browser_workflow
+        mediaSession = new MediaSessionCompat(this, "MediaSessionPlayerServ");
+        setSessionToken(mediaSession.getSessionToken());
+        sessionConnector = new MediaSessionConnector(mediaSession);
+        sessionConnector.setMetadataDeduplicationEnabled(true);
+
+        mediaBrowserPlaybackPreparer = new MediaBrowserPlaybackPreparer(
+                this,
+                sessionConnector::setCustomErrorMessage,
+                () -> sessionConnector.setCustomErrorMessage(null),
+                (playWhenReady) -> {
+                    if (player != null) {
+                        player.onPrepare();
+                    }
+                }
+        );
+        sessionConnector.setPlaybackPreparer(mediaBrowserPlaybackPreparer);
+
+        // Note: you might be tempted to create the player instance and call startForeground here,
+        // but be aware that the Android system might start the service just to perform media
+        // queries. In those cases creating a player instance is a waste of resources, and calling
+        // startForeground means creating a useless empty notification. In case it's really needed
+        // the player instance can be created here, but startForeground() should definitely not be
+        // called here unless the service is actually starting in the foreground, to avoid the
+        // useless notification.
     }
 
     @Override
     public int onStartCommand(final Intent intent, final int flags, final int startId) {
         if (DEBUG) {
             Log.d(TAG, "onStartCommand() called with: intent = [" + intent
+                    + "], extras = [" + BundleKt.toDebugString(intent.getExtras())
                     + "], flags = [" + flags + "], startId = [" + startId + "]");
         }
 
-        /*
-        Be sure that the player notification is set and the service is started in foreground,
-        otherwise, the app may crash on Android 8+ as the service would never be put in the
-        foreground while we said to the system we would do so
-        The service is always requested to be started in foreground, so always creating a
-        notification if there is no one already and starting the service in foreground should
-        not create any issues
-        If the service is already started in foreground, requesting it to be started shouldn't
-        do anything
-         */
-        if (player != null) {
+        // All internal NewPipe intents used to interact with the player, that are sent to the
+        // PlayerService using startForegroundService(), will have SHOULD_START_FOREGROUND_EXTRA,
+        // to ensure startForeground() is called (otherwise Android will force-crash the app).
+        if (intent.getBooleanExtra(SHOULD_START_FOREGROUND_EXTRA, false)) {
+            final boolean playerWasNull = (player == null);
+            if (playerWasNull) {
+                // make sure the player exists, in case the service was resumed
+                player = new Player(this, mediaSession, sessionConnector);
+            }
+
+            // Be sure that the player notification is set and the service is started in foreground,
+            // otherwise, the app may crash on Android 8+ as the service would never be put in the
+            // foreground while we said to the system we would do so. The service is always
+            // requested to be started in foreground, so always creating a notification if there is
+            // no one already and starting the service in foreground should not create any issues.
+            // If the service is already started in foreground, requesting it to be started
+            // shouldn't do anything.
             player.UIs().get(NotificationPlayerUi.class)
                     .ifPresent(NotificationPlayerUi::createNotificationAndStartForeground);
+
+            if (playerWasNull && onPlayerStartedOrStopped != null) {
+                // notify that a new player was created (but do it after creating the foreground
+                // notification just to make sure we don't incur, due to slowness, in
+                // "Context.startForegroundService() did not then call Service.startForeground()")
+                onPlayerStartedOrStopped.accept(player);
+            }
         }
 
         if (Intent.ACTION_MEDIA_BUTTON.equals(intent.getAction())
@@ -100,7 +167,7 @@ public final class PlayerService extends Service {
             Stop the service in this case, which will be removed from the foreground and its
             notification cancelled in its destruction
              */
-            stopSelf();
+            destroyPlayerAndStopService();
             return START_NOT_STICKY;
         }
 
@@ -142,29 +209,84 @@ public final class PlayerService extends Service {
         if (DEBUG) {
             Log.d(TAG, "destroy() called");
         }
+        super.onDestroy();
+
         cleanup();
+
+        mediaBrowserPlaybackPreparer.dispose();
+        mediaSession.release();
+        mediaBrowserImpl.dispose();
     }
 
     private void cleanup() {
         if (player != null) {
+            if (onPlayerStartedOrStopped != null) {
+                // notify that the player is being destroyed
+                onPlayerStartedOrStopped.accept(null);
+            }
             player.destroy();
             player = null;
         }
+
+        // Should already be handled by MediaSessionPlayerUi, but just to be sure.
+        mediaSession.setActive(false);
+
+        // Should already be handled by NotificationUtil.cancelNotificationAndStopForeground() in
+        // NotificationPlayerUi, but let's make sure that the foreground service is stopped.
+        ServiceCompat.stopForeground(this, ServiceCompat.STOP_FOREGROUND_REMOVE);
     }
 
-    public void stopService() {
+    /**
+     * Destroys the player and allows the player instance to be garbage collected. Sets the media
+     * session to inactive. Stops the foreground service and removes the player notification
+     * associated with it. Tries to stop the {@link PlayerService} completely, but this step will
+     * have no effect in case some service connection still uses the service (e.g. the Android Auto
+     * system accesses the media browser even when no player is running).
+     */
+    public void destroyPlayerAndStopService() {
+        if (DEBUG) {
+            Log.d(TAG, "destroyPlayerAndStopService() called");
+        }
+
         cleanup();
-        stopSelf();
+
+        // This only really stops the service if there are no other service connections (see docs):
+        // for example the (Android Auto) media browser binder will block stopService().
+        // This is why we also stopForeground() above, to make sure the notification is removed.
+        // If we were to call stopSelf(), then the service would be surely stopped (regardless of
+        // other service connections), but this would be a waste of resources since the service
+        // would be immediately restarted by those same connections to perform the queries.
+        stopService(new Intent(this, PlayerService.class));
     }
 
     @Override
     protected void attachBaseContext(final Context base) {
         super.attachBaseContext(AudioServiceLeakFix.preventLeakOf(base));
     }
+    //endregion
 
+    //region Bind
     @Override
     public IBinder onBind(final Intent intent) {
-        return mBinder;
+        if (DEBUG) {
+            Log.d(TAG, "onBind() called with: intent = [" + intent
+                    + "], extras = [" + BundleKt.toDebugString(intent.getExtras()) + "]");
+        }
+
+        if (BIND_PLAYER_HOLDER_ACTION.equals(intent.getAction())) {
+            // Note that this binder might be reused multiple times while the service is alive, even
+            // after unbind() has been called: https://stackoverflow.com/a/8794930 .
+            return mBinder;
+
+        } else if (MediaBrowserServiceCompat.SERVICE_INTERFACE.equals(intent.getAction())) {
+            // MediaBrowserService also uses its own binder, so for actions related to the media
+            // browser service, pass the onBind to the superclass.
+            return super.onBind(intent);
+
+        } else {
+            // This is an unknown request, avoid returning any binder to not leak objects.
+            return null;
+        }
     }
 
     public static class LocalBinder extends Binder {
@@ -177,9 +299,52 @@ public final class PlayerService extends Service {
         public PlayerService getService() {
             return playerService.get();
         }
+    }
 
-        public Player getPlayer() {
-            return playerService.get().player;
+    /**
+     * @return the current active player instance. May be null, since the player service can outlive
+     * the player e.g. to respond to Android Auto media browser queries.
+     */
+    @Nullable
+    public Player getPlayer() {
+        return player;
+    }
+
+    /**
+     * Sets the listener that will be called when the player is started or stopped. If a
+     * {@code null} listener is passed, then the current listener will be unset. The parameter taken
+     * by the {@link Consumer} can be null to indicate that the player is stopping.
+     * @param listener the listener to set or unset
+     */
+    public void setPlayerListener(@Nullable final Consumer<Player> listener) {
+        this.onPlayerStartedOrStopped = listener;
+        if (listener != null) {
+            // if there is no player, then `null` will be sent here, to ensure the state is synced
+            listener.accept(player);
         }
     }
+    //endregion
+
+    //region Media browser
+    @Override
+    public BrowserRoot onGetRoot(@NonNull final String clientPackageName,
+                                 final int clientUid,
+                                 @Nullable final Bundle rootHints) {
+        // TODO check if the accessing package has permission to view data
+        return mediaBrowserImpl.onGetRoot(clientPackageName, clientUid, rootHints);
+    }
+
+    @Override
+    public void onLoadChildren(@NonNull final String parentId,
+                               @NonNull final Result<List<MediaBrowserCompat.MediaItem>> result) {
+        mediaBrowserImpl.onLoadChildren(parentId, result);
+    }
+
+    @Override
+    public void onSearch(@NonNull final String query,
+                         final Bundle extras,
+                         @NonNull final Result<List<MediaBrowserCompat.MediaItem>> result) {
+        mediaBrowserImpl.onSearch(query, result);
+    }
+    //endregion
 }

app/src/main/java/org/schabi/newpipe/player/event/PlayerServiceExtendedEventListener.java

@@ -1,11 +1,48 @@
 package org.schabi.newpipe.player.event;
 
+import androidx.annotation.NonNull;
+
 import org.schabi.newpipe.player.PlayerService;
 import org.schabi.newpipe.player.Player;
 
+/**
+ * In addition to {@link PlayerServiceEventListener}, provides callbacks for service and player
+ * connections and disconnections. "Connected" here means that the service (resp. the
+ * player) is running and is bound to {@link org.schabi.newpipe.player.helper.PlayerHolder}.
+ * "Disconnected" means that either the service (resp. the player) was stopped completely, or that
+ * {@link org.schabi.newpipe.player.helper.PlayerHolder} is not bound.
+ */
 public interface PlayerServiceExtendedEventListener extends PlayerServiceEventListener {
-    void onServiceConnected(Player player,
-                            PlayerService playerService,
-                            boolean playAfterConnect);
+    /**
+     * The player service just connected to {@link org.schabi.newpipe.player.helper.PlayerHolder},
+     * but the player may not be active at this moment, e.g. in case the service is running to
+     * respond to Android Auto media browser queries without playing anything.
+     * {@link #onPlayerConnected(Player, boolean)} will be called right after this function if there
+     * is a player.
+     *
+     * @param playerService the newly connected player service
+     */
+    void onServiceConnected(@NonNull PlayerService playerService);
+
+    /**
+     * The player service is already connected and the player was just started.
+     *
+     * @param player the newly connected or started player
+     * @param playAfterConnect whether to open the video player in the video details fragment
+     */
+    void onPlayerConnected(@NonNull Player player, boolean playAfterConnect);
+
+    /**
+     * The player got disconnected, for one of these reasons: the player is getting closed while
+     * leaving the service open for future media browser queries, the service is stopping
+     * completely, or {@link org.schabi.newpipe.player.helper.PlayerHolder} is unbinding.
+     */
+    void onPlayerDisconnected();
+
+    /**
+     * The service got disconnected from {@link org.schabi.newpipe.player.helper.PlayerHolder},
+     * either because {@link org.schabi.newpipe.player.helper.PlayerHolder} is unbinding or because
+     * the service is stopping completely.
+     */
     void onServiceDisconnected();
 }

app/src/main/java/org/schabi/newpipe/player/helper/PlayerHolder.java

@@ -22,6 +22,10 @@ import org.schabi.newpipe.player.PlayerType;
 import org.schabi.newpipe.player.event.PlayerServiceEventListener;
 import org.schabi.newpipe.player.event.PlayerServiceExtendedEventListener;
 import org.schabi.newpipe.player.playqueue.PlayQueue;
+import org.schabi.newpipe.util.NavigationHelper;
+
+import java.util.Optional;
+import java.util.function.Consumer;
 
 public final class PlayerHolder {
 
@@ -44,7 +48,16 @@ public final class PlayerHolder {
     private final PlayerServiceConnection serviceConnection = new PlayerServiceConnection();
     private boolean bound;
     @Nullable private PlayerService playerService;
-    @Nullable private Player player;
+
+    private Optional<Player> getPlayer() {
+        return Optional.ofNullable(playerService)
+                .flatMap(s -> Optional.ofNullable(s.getPlayer()));
+    }
+
+    private Optional<PlayQueue> getPlayQueue() {
+        // player play queue might be null e.g. while player is starting
+        return getPlayer().flatMap(p -> Optional.ofNullable(p.getPlayQueue()));
+    }
 
     /**
      * Returns the current {@link PlayerType} of the {@link PlayerService} service,
@@ -54,21 +67,15 @@ public final class PlayerHolder {
      */
     @Nullable
     public PlayerType getType() {
-        if (player == null) {
-            return null;
-        }
-        return player.getPlayerType();
+        return getPlayer().map(Player::getPlayerType).orElse(null);
     }
 
     public boolean isPlaying() {
-        if (player == null) {
-            return false;
-        }
-        return player.isPlaying();
+        return getPlayer().map(Player::isPlaying).orElse(false);
     }
 
     public boolean isPlayerOpen() {
-        return player != null;
+        return getPlayer().isPresent();
     }
 
     /**
@@ -77,7 +84,7 @@ public final class PlayerHolder {
      * @return true only if the player is open and its play queue is ready (i.e. it is not null)
      */
     public boolean isPlayQueueReady() {
-        return player != null && player.getPlayQueue() != null;
+        return getPlayQueue().isPresent();
     }
 
     public boolean isBound() {
@@ -85,18 +92,11 @@ public final class PlayerHolder {
     }
 
     public int getQueueSize() {
-        if (player == null || player.getPlayQueue() == null) {
-            // player play queue might be null e.g. while player is starting
-            return 0;
-        }
-        return player.getPlayQueue().size();
+        return getPlayQueue().map(PlayQueue::size).orElse(0);
     }
 
     public int getQueuePosition() {
-        if (player == null || player.getPlayQueue() == null) {
-            return 0;
-        }
-        return player.getPlayQueue().getIndex();
+        return getPlayQueue().map(PlayQueue::getIndex).orElse(0);
     }
 
     public void setListener(@Nullable final PlayerServiceExtendedEventListener newListener) {
@@ -107,9 +107,10 @@ public final class PlayerHolder {
         }
 
         // Force reload data from service
-        if (player != null) {
-            listener.onServiceConnected(player, playerService, false);
+        if (playerService != null) {
+            listener.onServiceConnected(playerService);
             startPlayerListener();
+            // ^ will call listener.onPlayerConnected() down the line if there is an active player
         }
     }
 
@@ -121,6 +122,9 @@ public final class PlayerHolder {
 
     public void startService(final boolean playAfterConnect,
                              final PlayerServiceExtendedEventListener newListener) {
+        if (DEBUG) {
+            Log.d(TAG, "startService() called with playAfterConnect=" + playAfterConnect);
+        }
         final Context context = getCommonContext();
         setListener(newListener);
         if (bound) {
@@ -130,14 +134,24 @@ public final class PlayerHolder {
         // and NullPointerExceptions inside the service because the service will be
         // bound twice. Prevent it with unbinding first
         unbind(context);
-        ContextCompat.startForegroundService(context, new Intent(context, PlayerService.class));
+        final Intent intent = new Intent(context, PlayerService.class);
+        intent.putExtra(PlayerService.SHOULD_START_FOREGROUND_EXTRA, true);
+        ContextCompat.startForegroundService(context, intent);
         serviceConnection.doPlayAfterConnect(playAfterConnect);
         bind(context);
     }
 
     public void stopService() {
+        if (DEBUG) {
+            Log.d(TAG, "stopService() called");
+        }
+        if (playerService != null) {
+            playerService.destroyPlayerAndStopService();
+        }
         final Context context = getCommonContext();
         unbind(context);
+        // destroyPlayerAndStopService() already runs the next line of code, but run it again just
+        // to make sure to stop the service even if playerService is null by any chance.
         context.stopService(new Intent(context, PlayerService.class));
     }
 
@@ -167,11 +181,16 @@ public final class PlayerHolder {
             final PlayerService.LocalBinder localBinder = (PlayerService.LocalBinder) service;
 
             playerService = localBinder.getService();
-            player = localBinder.getPlayer();
             if (listener != null) {
-                listener.onServiceConnected(player, playerService, playAfterConnect);
+                listener.onServiceConnected(playerService);
+                getPlayer().ifPresent(p -> listener.onPlayerConnected(p, playAfterConnect));
             }
             startPlayerListener();
+            // ^ will call listener.onPlayerConnected() down the line if there is an active player
+
+            // notify the main activity that binding the service has completed, so that it can
+            // open the bottom mini-player
+            NavigationHelper.sendPlayerStartedEvent(localBinder.getService());
         }
     }
 
@@ -179,15 +198,28 @@ public final class PlayerHolder {
         if (DEBUG) {
             Log.d(TAG, "bind() called");
         }
-
-        final Intent serviceIntent = new Intent(context, PlayerService.class);
-        bound = context.bindService(serviceIntent, serviceConnection,
-                Context.BIND_AUTO_CREATE);
+        // BIND_AUTO_CREATE starts the service if it's not already running
+        bound = bind(context, Context.BIND_AUTO_CREATE);
         if (!bound) {
             context.unbindService(serviceConnection);
         }
     }
 
+    public void tryBindIfNeeded(final Context context) {
+        if (!bound) {
+            // flags=0 means the service will not be started if it does not already exist. In this
+            // case the return value is not useful, as a value of "true" does not really indicate
+            // that the service is going to be bound.
+            bind(context, 0);
+        }
+    }
+
+    private boolean bind(final Context context, final int flags) {
+        final Intent serviceIntent = new Intent(context, PlayerService.class);
+        serviceIntent.setAction(PlayerService.BIND_PLAYER_HOLDER_ACTION);
+        return context.bindService(serviceIntent, serviceConnection, flags);
+    }
+
     private void unbind(final Context context) {
         if (DEBUG) {
             Log.d(TAG, "unbind() called");
@@ -198,25 +230,32 @@ public final class PlayerHolder {
             bound = false;
             stopPlayerListener();
             playerService = null;
-            player = null;
             if (listener != null) {
+                listener.onPlayerDisconnected();
                 listener.onServiceDisconnected();
             }
         }
     }
 
     private void startPlayerListener() {
-        if (player != null) {
-            player.setFragmentListener(internalListener);
+        if (playerService != null) {
+            // setting the player listener will take care of calling relevant callbacks if the
+            // player in the service is (not) already active, also see playerStateListener below
+            playerService.setPlayerListener(playerStateListener);
         }
+        getPlayer().ifPresent(p -> p.setFragmentListener(internalListener));
     }
 
     private void stopPlayerListener() {
-        if (player != null) {
-            player.removeFragmentListener(internalListener);
+        if (playerService != null) {
+            playerService.setPlayerListener(null);
         }
+        getPlayer().ifPresent(p -> p.removeFragmentListener(internalListener));
     }
 
+    /**
+     * This listener will be held by the players created by {@link PlayerService}.
+     */
     private final PlayerServiceEventListener internalListener =
             new PlayerServiceEventListener() {
                 @Override
@@ -303,4 +342,23 @@ public final class PlayerHolder {
                     unbind(getCommonContext());
                 }
             };
+
+    /**
+     * This listener will be held by bound {@link PlayerService}s to notify of the player starting
+     * or stopping. This is necessary since the service outlives the player e.g. to answer Android
+     * Auto media browser queries.
+     */
+    private final Consumer<Player> playerStateListener = (@Nullable final Player player) -> {
+        if (listener != null) {
+            if (player == null) {
+                // player.fragmentListener=null is already done by player.stopActivityBinding(),
+                // which is called by player.destroy(), which is in turn called by PlayerService
+                // before setting its player to null
+                listener.onPlayerDisconnected();
+            } else {
+                listener.onPlayerConnected(player, serviceConnection.playAfterConnect);
+                player.setFragmentListener(internalListener);
+            }
+        }
+    };
 }

app/src/main/java/org/schabi/newpipe/player/mediabrowser/MediaBrowserCommon.kt

@@ -0,0 +1,40 @@
+package org.schabi.newpipe.player.mediabrowser
+
+import org.schabi.newpipe.BuildConfig
+import org.schabi.newpipe.extractor.InfoItem.InfoType
+import org.schabi.newpipe.extractor.exceptions.ContentNotAvailableException
+
+internal const val ID_AUTHORITY = BuildConfig.APPLICATION_ID
+internal const val ID_ROOT = "//$ID_AUTHORITY"
+internal const val ID_BOOKMARKS = "playlists"
+internal const val ID_HISTORY = "history"
+internal const val ID_INFO_ITEM = "item"
+
+internal const val ID_LOCAL = "local"
+internal const val ID_REMOTE = "remote"
+internal const val ID_URL = "url"
+internal const val ID_STREAM = "stream"
+internal const val ID_PLAYLIST = "playlist"
+internal const val ID_CHANNEL = "channel"
+
+internal fun infoItemTypeToString(type: InfoType): String {
+    return when (type) {
+        InfoType.STREAM -> ID_STREAM
+        InfoType.PLAYLIST -> ID_PLAYLIST
+        InfoType.CHANNEL -> ID_CHANNEL
+        else -> throw IllegalStateException("Unexpected value: $type")
+    }
+}
+
+internal fun infoItemTypeFromString(type: String): InfoType {
+    return when (type) {
+        ID_STREAM -> InfoType.STREAM
+        ID_PLAYLIST -> InfoType.PLAYLIST
+        ID_CHANNEL -> InfoType.CHANNEL
+        else -> throw IllegalStateException("Unexpected value: $type")
+    }
+}
+
+internal fun parseError(mediaId: String): ContentNotAvailableException {
+    return ContentNotAvailableException("Failed to parse media ID $mediaId")
+}

app/src/main/java/org/schabi/newpipe/player/mediabrowser/MediaBrowserImpl.kt

@@ -0,0 +1,399 @@
+package org.schabi.newpipe.player.mediabrowser
+
+import android.content.ContentResolver
+import android.content.Context
+import android.net.Uri
+import android.os.Bundle
+import android.support.v4.media.MediaBrowserCompat
+import android.support.v4.media.MediaDescriptionCompat
+import android.util.Log
+import androidx.annotation.DrawableRes
+import androidx.media.MediaBrowserServiceCompat
+import androidx.media.MediaBrowserServiceCompat.Result
+import androidx.media.utils.MediaConstants
+import io.reactivex.rxjava3.core.Flowable
+import io.reactivex.rxjava3.core.Single
+import io.reactivex.rxjava3.disposables.CompositeDisposable
+import io.reactivex.rxjava3.schedulers.Schedulers
+import org.schabi.newpipe.MainActivity.DEBUG
+import org.schabi.newpipe.NewPipeDatabase
+import org.schabi.newpipe.R
+import org.schabi.newpipe.database.history.model.StreamHistoryEntry
+import org.schabi.newpipe.database.playlist.PlaylistLocalItem
+import org.schabi.newpipe.database.playlist.PlaylistStreamEntry
+import org.schabi.newpipe.database.playlist.model.PlaylistRemoteEntity
+import org.schabi.newpipe.extractor.InfoItem
+import org.schabi.newpipe.extractor.InfoItem.InfoType
+import org.schabi.newpipe.extractor.channel.ChannelInfoItem
+import org.schabi.newpipe.extractor.exceptions.ContentNotAvailableException
+import org.schabi.newpipe.extractor.playlist.PlaylistInfoItem
+import org.schabi.newpipe.extractor.search.SearchInfo
+import org.schabi.newpipe.extractor.stream.StreamInfoItem
+import org.schabi.newpipe.local.bookmark.MergedPlaylistManager
+import org.schabi.newpipe.local.playlist.LocalPlaylistManager
+import org.schabi.newpipe.local.playlist.RemotePlaylistManager
+import org.schabi.newpipe.util.ExtractorHelper
+import org.schabi.newpipe.util.ServiceHelper
+import org.schabi.newpipe.util.image.ImageStrategy
+import java.util.function.Consumer
+
+/**
+ * This class is used to cleanly separate the Service implementation (in
+ * [org.schabi.newpipe.player.PlayerService]) and the media browser implementation (in this file).
+ *
+ * @param notifyChildrenChanged takes the parent id of the children that changed
+ */
+class MediaBrowserImpl(
+    private val context: Context,
+    notifyChildrenChanged: Consumer<String>, // parentId
+) {
+    private val database = NewPipeDatabase.getInstance(context)
+    private var disposables = CompositeDisposable()
+
+    init {
+        // this will listen to changes in the bookmarks until this MediaBrowserImpl is dispose()d
+        disposables.add(
+            getMergedPlaylists().subscribe { notifyChildrenChanged.accept(ID_BOOKMARKS) }
+        )
+    }
+
+    //region Cleanup
+    fun dispose() {
+        disposables.dispose()
+    }
+    //endregion
+
+    //region onGetRoot
+    fun onGetRoot(
+        clientPackageName: String,
+        clientUid: Int,
+        rootHints: Bundle?
+    ): MediaBrowserServiceCompat.BrowserRoot {
+        if (DEBUG) {
+            Log.d(TAG, "onGetRoot($clientPackageName, $clientUid, $rootHints)")
+        }
+
+        val extras = Bundle()
+        extras.putBoolean(
+            MediaConstants.BROWSER_SERVICE_EXTRAS_KEY_SEARCH_SUPPORTED, true
+        )
+        return MediaBrowserServiceCompat.BrowserRoot(ID_ROOT, extras)
+    }
+    //endregion
+
+    //region onLoadChildren
+    fun onLoadChildren(parentId: String, result: Result<List<MediaBrowserCompat.MediaItem>>) {
+        if (DEBUG) {
+            Log.d(TAG, "onLoadChildren($parentId)")
+        }
+
+        result.detach() // allows sendResult() to happen later
+        disposables.add(
+            onLoadChildren(parentId)
+                .subscribe(
+                    { result.sendResult(it) },
+                    { throwable ->
+                        // null indicates an error, see the docs of MediaSessionCompat.onSearch()
+                        result.sendResult(null)
+                        Log.e(TAG, "onLoadChildren error for parentId=$parentId: $throwable")
+                    }
+                )
+        )
+    }
+
+    private fun onLoadChildren(parentId: String): Single<List<MediaBrowserCompat.MediaItem>> {
+        try {
+            val parentIdUri = Uri.parse(parentId)
+            val path = ArrayList(parentIdUri.pathSegments)
+
+            if (path.isEmpty()) {
+                return Single.just(
+                    listOf(
+                        createRootMediaItem(
+                            ID_BOOKMARKS,
+                            context.resources.getString(R.string.tab_bookmarks_short),
+                            R.drawable.ic_bookmark_white
+                        ),
+                        createRootMediaItem(
+                            ID_HISTORY,
+                            context.resources.getString(R.string.action_history),
+                            R.drawable.ic_history_white
+                        )
+                    )
+                )
+            }
+
+            when (/*val uriType = */path.removeAt(0)) {
+                ID_BOOKMARKS -> {
+                    if (path.isEmpty()) {
+                        return populateBookmarks()
+                    }
+                    if (path.size == 2) {
+                        val localOrRemote = path[0]
+                        val playlistId = path[1].toLong()
+                        if (localOrRemote == ID_LOCAL) {
+                            return populateLocalPlaylist(playlistId)
+                        } else if (localOrRemote == ID_REMOTE) {
+                            return populateRemotePlaylist(playlistId)
+                        }
+                    }
+                    Log.w(TAG, "Unknown playlist URI: $parentId")
+                    throw parseError(parentId)
+                }
+
+                ID_HISTORY -> return populateHistory()
+
+                else -> throw parseError(parentId)
+            }
+        } catch (e: ContentNotAvailableException) {
+            return Single.error(e)
+        }
+    }
+
+    private fun createRootMediaItem(
+        mediaId: String?,
+        folderName: String?,
+        @DrawableRes iconResId: Int
+    ): MediaBrowserCompat.MediaItem {
+        val builder = MediaDescriptionCompat.Builder()
+        builder.setMediaId(mediaId)
+        builder.setTitle(folderName)
+        val resources = context.resources
+        builder.setIconUri(
+            Uri.Builder()
+                .scheme(ContentResolver.SCHEME_ANDROID_RESOURCE)
+                .authority(resources.getResourcePackageName(iconResId))
+                .appendPath(resources.getResourceTypeName(iconResId))
+                .appendPath(resources.getResourceEntryName(iconResId))
+                .build()
+        )
+
+        val extras = Bundle()
+        extras.putString(
+            MediaConstants.DESCRIPTION_EXTRAS_KEY_CONTENT_STYLE_GROUP_TITLE,
+            context.getString(R.string.app_name)
+        )
+        builder.setExtras(extras)
+        return MediaBrowserCompat.MediaItem(
+            builder.build(),
+            MediaBrowserCompat.MediaItem.FLAG_BROWSABLE
+        )
+    }
+
+    private fun createPlaylistMediaItem(playlist: PlaylistLocalItem): MediaBrowserCompat.MediaItem {
+        val builder = MediaDescriptionCompat.Builder()
+        builder
+            .setMediaId(createMediaIdForInfoItem(playlist is PlaylistRemoteEntity, playlist.uid))
+            .setTitle(playlist.orderingName)
+            .setIconUri(playlist.thumbnailUrl?.let { Uri.parse(it) })
+
+        val extras = Bundle()
+        extras.putString(
+            MediaConstants.DESCRIPTION_EXTRAS_KEY_CONTENT_STYLE_GROUP_TITLE,
+            context.resources.getString(R.string.tab_bookmarks),
+        )
+        builder.setExtras(extras)
+        return MediaBrowserCompat.MediaItem(
+            builder.build(),
+            MediaBrowserCompat.MediaItem.FLAG_BROWSABLE,
+        )
+    }
+
+    private fun createInfoItemMediaItem(item: InfoItem): MediaBrowserCompat.MediaItem? {
+        val builder = MediaDescriptionCompat.Builder()
+        builder.setMediaId(createMediaIdForInfoItem(item))
+            .setTitle(item.name)
+
+        when (item.infoType) {
+            InfoType.STREAM -> builder.setSubtitle((item as StreamInfoItem).uploaderName)
+            InfoType.PLAYLIST -> builder.setSubtitle((item as PlaylistInfoItem).uploaderName)
+            InfoType.CHANNEL -> builder.setSubtitle((item as ChannelInfoItem).description)
+            else -> return null
+        }
+
+        ImageStrategy.choosePreferredImage(item.thumbnails)?.let {
+            builder.setIconUri(Uri.parse(it))
+        }
+
+        return MediaBrowserCompat.MediaItem(
+            builder.build(),
+            MediaBrowserCompat.MediaItem.FLAG_PLAYABLE
+        )
+    }
+
+    private fun buildMediaId(): Uri.Builder {
+        return Uri.Builder().authority(ID_AUTHORITY)
+    }
+
+    private fun buildPlaylistMediaId(playlistType: String?): Uri.Builder {
+        return buildMediaId()
+            .appendPath(ID_BOOKMARKS)
+            .appendPath(playlistType)
+    }
+
+    private fun buildLocalPlaylistItemMediaId(isRemote: Boolean, playlistId: Long): Uri.Builder {
+        return buildPlaylistMediaId(if (isRemote) ID_REMOTE else ID_LOCAL)
+            .appendPath(playlistId.toString())
+    }
+
+    private fun buildInfoItemMediaId(item: InfoItem): Uri.Builder {
+        return buildMediaId()
+            .appendPath(ID_INFO_ITEM)
+            .appendPath(infoItemTypeToString(item.infoType))
+            .appendPath(item.serviceId.toString())
+            .appendQueryParameter(ID_URL, item.url)
+    }
+
+    private fun createMediaIdForInfoItem(isRemote: Boolean, playlistId: Long): String {
+        return buildLocalPlaylistItemMediaId(isRemote, playlistId)
+            .build().toString()
+    }
+
+    private fun createLocalPlaylistStreamMediaItem(
+        playlistId: Long,
+        item: PlaylistStreamEntry,
+        index: Int,
+    ): MediaBrowserCompat.MediaItem {
+        val builder = MediaDescriptionCompat.Builder()
+        builder.setMediaId(createMediaIdForPlaylistIndex(false, playlistId, index))
+            .setTitle(item.streamEntity.title)
+            .setSubtitle(item.streamEntity.uploader)
+            .setIconUri(Uri.parse(item.streamEntity.thumbnailUrl))
+
+        return MediaBrowserCompat.MediaItem(
+            builder.build(),
+            MediaBrowserCompat.MediaItem.FLAG_PLAYABLE
+        )
+    }
+
+    private fun createRemotePlaylistStreamMediaItem(
+        playlistId: Long,
+        item: StreamInfoItem,
+        index: Int,
+    ): MediaBrowserCompat.MediaItem {
+        val builder = MediaDescriptionCompat.Builder()
+        builder.setMediaId(createMediaIdForPlaylistIndex(true, playlistId, index))
+            .setTitle(item.name)
+            .setSubtitle(item.uploaderName)
+
+        ImageStrategy.choosePreferredImage(item.thumbnails)?.let {
+            builder.setIconUri(Uri.parse(it))
+        }
+
+        return MediaBrowserCompat.MediaItem(
+            builder.build(),
+            MediaBrowserCompat.MediaItem.FLAG_PLAYABLE
+        )
+    }
+
+    private fun createMediaIdForPlaylistIndex(
+        isRemote: Boolean,
+        playlistId: Long,
+        index: Int,
+    ): String {
+        return buildLocalPlaylistItemMediaId(isRemote, playlistId)
+            .appendPath(index.toString())
+            .build().toString()
+    }
+
+    private fun createMediaIdForInfoItem(item: InfoItem): String {
+        return buildInfoItemMediaId(item).build().toString()
+    }
+
+    private fun populateHistory(): Single<List<MediaBrowserCompat.MediaItem>> {
+        val history = database.streamHistoryDAO().getHistory().firstOrError()
+        return history.map { items ->
+            items.map { this.createHistoryMediaItem(it) }
+        }
+    }
+
+    private fun createHistoryMediaItem(streamHistoryEntry: StreamHistoryEntry): MediaBrowserCompat.MediaItem {
+        val builder = MediaDescriptionCompat.Builder()
+        val mediaId = buildMediaId()
+            .appendPath(ID_HISTORY)
+            .appendPath(streamHistoryEntry.streamId.toString())
+            .build().toString()
+        builder.setMediaId(mediaId)
+            .setTitle(streamHistoryEntry.streamEntity.title)
+            .setSubtitle(streamHistoryEntry.streamEntity.uploader)
+            .setIconUri(Uri.parse(streamHistoryEntry.streamEntity.thumbnailUrl))
+
+        return MediaBrowserCompat.MediaItem(
+            builder.build(),
+            MediaBrowserCompat.MediaItem.FLAG_PLAYABLE
+        )
+    }
+
+    private fun getMergedPlaylists(): Flowable<MutableList<PlaylistLocalItem>> {
+        return MergedPlaylistManager.getMergedOrderedPlaylists(
+            LocalPlaylistManager(database),
+            RemotePlaylistManager(database)
+        )
+    }
+
+    private fun populateBookmarks(): Single<List<MediaBrowserCompat.MediaItem>> {
+        val playlists = getMergedPlaylists().firstOrError()
+        return playlists.map { playlist ->
+            playlist.map { this.createPlaylistMediaItem(it) }
+        }
+    }
+
+    private fun populateLocalPlaylist(playlistId: Long): Single<List<MediaBrowserCompat.MediaItem>> {
+        val playlist = LocalPlaylistManager(database).getPlaylistStreams(playlistId).firstOrError()
+        return playlist.map { items ->
+            items.mapIndexed { index, item ->
+                createLocalPlaylistStreamMediaItem(playlistId, item, index)
+            }
+        }
+    }
+
+    private fun populateRemotePlaylist(playlistId: Long): Single<List<MediaBrowserCompat.MediaItem>> {
+        return RemotePlaylistManager(database).getPlaylist(playlistId).firstOrError()
+            .flatMap { ExtractorHelper.getPlaylistInfo(it.serviceId, it.url, false) }
+            .map {
+                // ignore it.errors, i.e. ignore errors about specific items, since there would
+                // be no way to show the error properly in Android Auto anyway
+                it.relatedItems.mapIndexed { index, item ->
+                    createRemotePlaylistStreamMediaItem(playlistId, item, index)
+                }
+            }
+    }
+    //endregion
+
+    //region Search
+    fun onSearch(
+        query: String,
+        result: Result<List<MediaBrowserCompat.MediaItem>>
+    ) {
+        if (DEBUG) {
+            Log.d(TAG, "onSearch($query)")
+        }
+
+        result.detach() // allows sendResult() to happen later
+        disposables.add(
+            searchMusicBySongTitle(query)
+                // ignore it.errors, i.e. ignore errors about specific items, since there would
+                // be no way to show the error properly in Android Auto anyway
+                .map { it.relatedItems.mapNotNull(this::createInfoItemMediaItem) }
+                .subscribeOn(Schedulers.io())
+                .subscribe(
+                    { result.sendResult(it) },
+                    { throwable ->
+                        // null indicates an error, see the docs of MediaSessionCompat.onSearch()
+                        result.sendResult(null)
+                        Log.e(TAG, "Search error for query=\"$query\": $throwable")
+                    }
+                )
+        )
+    }
+
+    private fun searchMusicBySongTitle(query: String?): Single<SearchInfo> {
+        val serviceId = ServiceHelper.getSelectedServiceId(context)
+        return ExtractorHelper.searchFor(serviceId, query, listOf(), "")
+    }
+    //endregion
+
+    companion object {
+        private val TAG: String = MediaBrowserImpl::class.java.getSimpleName()
+    }
+}

app/src/main/java/org/schabi/newpipe/player/mediabrowser/MediaBrowserPlaybackPreparer.kt

@@ -0,0 +1,259 @@
+package org.schabi.newpipe.player.mediabrowser
+
+import android.content.Context
+import android.net.Uri
+import android.os.Bundle
+import android.os.ResultReceiver
+import android.support.v4.media.session.PlaybackStateCompat
+import android.util.Log
+import com.google.android.exoplayer2.Player
+import com.google.android.exoplayer2.ext.mediasession.MediaSessionConnector.PlaybackPreparer
+import io.reactivex.rxjava3.android.schedulers.AndroidSchedulers
+import io.reactivex.rxjava3.core.Single
+import io.reactivex.rxjava3.disposables.Disposable
+import io.reactivex.rxjava3.schedulers.Schedulers
+import org.schabi.newpipe.MainActivity
+import org.schabi.newpipe.NewPipeDatabase
+import org.schabi.newpipe.R
+import org.schabi.newpipe.extractor.InfoItem.InfoType
+import org.schabi.newpipe.extractor.exceptions.ContentNotAvailableException
+import org.schabi.newpipe.extractor.linkhandler.ListLinkHandler
+import org.schabi.newpipe.local.playlist.LocalPlaylistManager
+import org.schabi.newpipe.local.playlist.RemotePlaylistManager
+import org.schabi.newpipe.player.playqueue.ChannelTabPlayQueue
+import org.schabi.newpipe.player.playqueue.PlayQueue
+import org.schabi.newpipe.player.playqueue.PlaylistPlayQueue
+import org.schabi.newpipe.player.playqueue.SinglePlayQueue
+import org.schabi.newpipe.util.ChannelTabHelper
+import org.schabi.newpipe.util.ExtractorHelper
+import org.schabi.newpipe.util.NavigationHelper
+import java.util.function.BiConsumer
+import java.util.function.Consumer
+
+/**
+ * This class is used to cleanly separate the Service implementation (in
+ * [org.schabi.newpipe.player.PlayerService]) and the playback preparer implementation (in this
+ * file). We currently use the playback preparer only in conjunction with the media browser: the
+ * playback preparer will receive the media URLs generated by [MediaBrowserImpl] and will start
+ * playback of the corresponding streams or playlists.
+ *
+ * @param setMediaSessionError takes an error String and an error code from [PlaybackStateCompat],
+ * calls `sessionConnector.setCustomErrorMessage(errorString, errorCode)`
+ * @param clearMediaSessionError calls `sessionConnector.setCustomErrorMessage(null)`
+ * @param onPrepare takes playWhenReady, calls `player.prepare()`; this is needed because
+ * `MediaSessionConnector`'s `onPlay()` method calls this class'  [onPrepare] instead of
+ * `player.prepare()` if the playback preparer is not null, but we want the original behavior
+ */
+class MediaBrowserPlaybackPreparer(
+    private val context: Context,
+    private val setMediaSessionError: BiConsumer<String, Int>, // error string, error code
+    private val clearMediaSessionError: Runnable,
+    private val onPrepare: Consumer<Boolean>,
+) : PlaybackPreparer {
+    private val database = NewPipeDatabase.getInstance(context)
+    private var disposable: Disposable? = null
+
+    fun dispose() {
+        disposable?.dispose()
+    }
+
+    //region Overrides
+    override fun getSupportedPrepareActions(): Long {
+        return PlaybackStateCompat.ACTION_PLAY_FROM_MEDIA_ID
+    }
+
+    override fun onPrepare(playWhenReady: Boolean) {
+        onPrepare.accept(playWhenReady)
+    }
+
+    override fun onPrepareFromMediaId(mediaId: String, playWhenReady: Boolean, extras: Bundle?) {
+        if (MainActivity.DEBUG) {
+            Log.d(TAG, "onPrepareFromMediaId($mediaId, $playWhenReady, $extras)")
+        }
+
+        disposable?.dispose()
+        disposable = extractPlayQueueFromMediaId(mediaId)
+            .subscribeOn(Schedulers.io())
+            .observeOn(AndroidSchedulers.mainThread())
+            .subscribe(
+                { playQueue ->
+                    clearMediaSessionError.run()
+                    NavigationHelper.playOnBackgroundPlayer(context, playQueue, playWhenReady)
+                },
+                { throwable ->
+                    Log.e(TAG, "Failed to start playback of media ID [$mediaId]", throwable)
+                    onPrepareError()
+                }
+            )
+    }
+
+    override fun onPrepareFromSearch(query: String, playWhenReady: Boolean, extras: Bundle?) {
+        onUnsupportedError()
+    }
+
+    override fun onPrepareFromUri(uri: Uri, playWhenReady: Boolean, extras: Bundle?) {
+        onUnsupportedError()
+    }
+
+    override fun onCommand(
+        player: Player,
+        command: String,
+        extras: Bundle?,
+        cb: ResultReceiver?
+    ): Boolean {
+        return false
+    }
+    //endregion
+
+    //region Errors
+    private fun onUnsupportedError() {
+        setMediaSessionError.accept(
+            context.getString(R.string.content_not_supported),
+            PlaybackStateCompat.ERROR_CODE_NOT_SUPPORTED
+        )
+    }
+
+    private fun onPrepareError() {
+        setMediaSessionError.accept(
+            context.getString(R.string.error_snackbar_message),
+            PlaybackStateCompat.ERROR_CODE_APP_ERROR
+        )
+    }
+    //endregion
+
+    //region Building play queues from playlists and history
+    private fun extractLocalPlayQueue(playlistId: Long, index: Int): Single<PlayQueue> {
+        return LocalPlaylistManager(database).getPlaylistStreams(playlistId).firstOrError()
+            .map { items -> SinglePlayQueue(items.map { it.toStreamInfoItem() }, index) }
+    }
+
+    private fun extractRemotePlayQueue(playlistId: Long, index: Int): Single<PlayQueue> {
+        return RemotePlaylistManager(database).getPlaylist(playlistId).firstOrError()
+            .flatMap { ExtractorHelper.getPlaylistInfo(it.serviceId, it.url, false) }
+            // ignore info.errors, i.e. ignore errors about specific items, since there would
+            // be no way to show the error properly in Android Auto anyway
+            .map { info -> PlaylistPlayQueue(info, index) }
+    }
+
+    private fun extractPlayQueueFromMediaId(mediaId: String): Single<PlayQueue> {
+        try {
+            val mediaIdUri = Uri.parse(mediaId)
+            val path = ArrayList(mediaIdUri.pathSegments)
+            if (path.isEmpty()) {
+                throw parseError(mediaId)
+            }
+
+            return when (/*val uriType = */path.removeAt(0)) {
+                ID_BOOKMARKS -> extractPlayQueueFromPlaylistMediaId(
+                    mediaId,
+                    path,
+                    mediaIdUri.getQueryParameter(ID_URL)
+                )
+
+                ID_HISTORY -> extractPlayQueueFromHistoryMediaId(mediaId, path)
+
+                ID_INFO_ITEM -> extractPlayQueueFromInfoItemMediaId(
+                    mediaId,
+                    path,
+                    mediaIdUri.getQueryParameter(ID_URL) ?: throw parseError(mediaId)
+                )
+
+                else -> throw parseError(mediaId)
+            }
+        } catch (e: ContentNotAvailableException) {
+            return Single.error(e)
+        }
+    }
+
+    @Throws(ContentNotAvailableException::class)
+    private fun extractPlayQueueFromPlaylistMediaId(
+        mediaId: String,
+        path: MutableList<String>,
+        url: String?,
+    ): Single<PlayQueue> {
+        if (path.isEmpty()) {
+            throw parseError(mediaId)
+        }
+
+        when (val playlistType = path.removeAt(0)) {
+            ID_LOCAL, ID_REMOTE -> {
+                if (path.size != 2) {
+                    throw parseError(mediaId)
+                }
+                val playlistId = path[0].toLong()
+                val index = path[1].toInt()
+                return if (playlistType == ID_LOCAL)
+                    extractLocalPlayQueue(playlistId, index)
+                else
+                    extractRemotePlayQueue(playlistId, index)
+            }
+
+            ID_URL -> {
+                if (path.size != 1 || url == null) {
+                    throw parseError(mediaId)
+                }
+
+                val serviceId = path[0].toInt()
+                return ExtractorHelper.getPlaylistInfo(serviceId, url, false)
+                    .map { PlaylistPlayQueue(it) }
+            }
+
+            else -> throw parseError(mediaId)
+        }
+    }
+
+    @Throws(ContentNotAvailableException::class)
+    private fun extractPlayQueueFromHistoryMediaId(
+        mediaId: String,
+        path: List<String>,
+    ): Single<PlayQueue> {
+        if (path.size != 1) {
+            throw parseError(mediaId)
+        }
+
+        val streamId = path[0].toLong()
+        return database.streamHistoryDAO().getHistory()
+            .firstOrError()
+            .map { items ->
+                val infoItems = items
+                    .filter { it.streamId == streamId }
+                    .map { it.toStreamInfoItem() }
+                SinglePlayQueue(infoItems, 0)
+            }
+    }
+
+    @Throws(ContentNotAvailableException::class)
+    private fun extractPlayQueueFromInfoItemMediaId(
+        mediaId: String,
+        path: List<String>,
+        url: String,
+    ): Single<PlayQueue> {
+        if (path.size != 2) {
+            throw parseError(mediaId)
+        }
+
+        val serviceId = path[1].toInt()
+        return when (/*val infoItemType = */infoItemTypeFromString(path[0])) {
+            InfoType.STREAM -> ExtractorHelper.getStreamInfo(serviceId, url, false)
+                .map { SinglePlayQueue(it) }
+
+            InfoType.PLAYLIST -> ExtractorHelper.getPlaylistInfo(serviceId, url, false)
+                .map { PlaylistPlayQueue(it) }
+
+            InfoType.CHANNEL -> ExtractorHelper.getChannelInfo(serviceId, url, false)
+                .map { info ->
+                    val playableTab = info.tabs
+                        .firstOrNull { ChannelTabHelper.isStreamsTab(it) }
+                        ?: throw ContentNotAvailableException("No streams tab found")
+                    return@map ChannelTabPlayQueue(serviceId, ListLinkHandler(playableTab))
+                }
+
+            else -> throw parseError(mediaId)
+        }
+    }
+    //endregion
+
+    companion object {
+        private val TAG = MediaBrowserPlaybackPreparer::class.simpleName
+    }
+}

app/src/main/java/org/schabi/newpipe/player/mediasession/MediaSessionPlayerUi.java

@@ -38,10 +38,10 @@ public class MediaSessionPlayerUi extends PlayerUi
         implements SharedPreferences.OnSharedPreferenceChangeListener {
     private static final String TAG = "MediaSessUi";
 
-    @Nullable
-    private MediaSessionCompat mediaSession;
-    @Nullable
-    private MediaSessionConnector sessionConnector;
+    @NonNull
+    private final MediaSessionCompat mediaSession;
+    @NonNull
+    private final MediaSessionConnector sessionConnector;
 
     private final String ignoreHardwareMediaButtonsKey;
     private boolean shouldIgnoreHardwareMediaButtons = false;
@@ -50,9 +50,13 @@ public class MediaSessionPlayerUi extends PlayerUi
     private List<NotificationActionData> prevNotificationActions = List.of();
 
 
-    public MediaSessionPlayerUi(@NonNull final Player player) {
+    public MediaSessionPlayerUi(@NonNull final Player player,
+                                @NonNull final MediaSessionCompat mediaSession,
+                                @NonNull final MediaSessionConnector sessionConnector) {
         super(player);
-        ignoreHardwareMediaButtonsKey =
+        this.mediaSession = mediaSession;
+        this.sessionConnector = sessionConnector;
+        this.ignoreHardwareMediaButtonsKey =
                 context.getString(R.string.ignore_hardware_media_buttons_key);
     }
 
@@ -61,10 +65,8 @@ public class MediaSessionPlayerUi extends PlayerUi
         super.initPlayer();
         destroyPlayer(); // release previously used resources
 
-        mediaSession = new MediaSessionCompat(context, TAG);
         mediaSession.setActive(true);
 
-        sessionConnector = new MediaSessionConnector(mediaSession);
         sessionConnector.setQueueNavigator(new PlayQueueNavigator(mediaSession, player));
         sessionConnector.setPlayer(getForwardingPlayer());
 
@@ -89,27 +91,18 @@ public class MediaSessionPlayerUi extends PlayerUi
     public void destroyPlayer() {
         super.destroyPlayer();
         player.getPrefs().unregisterOnSharedPreferenceChangeListener(this);
-        if (sessionConnector != null) {
-            sessionConnector.setMediaButtonEventHandler(null);
-            sessionConnector.setPlayer(null);
-            sessionConnector.setQueueNavigator(null);
-            sessionConnector = null;
-        }
-        if (mediaSession != null) {
-            mediaSession.setActive(false);
-            mediaSession.release();
-            mediaSession = null;
-        }
+        sessionConnector.setMediaButtonEventHandler(null);
+        sessionConnector.setPlayer(null);
+        sessionConnector.setQueueNavigator(null);
+        mediaSession.setActive(false);
         prevNotificationActions = List.of();
     }
 
     @Override
     public void onThumbnailLoaded(@Nullable final Bitmap bitmap) {
         super.onThumbnailLoaded(bitmap);
-        if (sessionConnector != null) {
-            // the thumbnail is now loaded: invalidate the metadata to trigger a metadata update
-            sessionConnector.invalidateMediaSessionMetadata();
-        }
+        // the thumbnail is now loaded: invalidate the metadata to trigger a metadata update
+        sessionConnector.invalidateMediaSessionMetadata();
     }
 
 
@@ -200,8 +193,8 @@ public class MediaSessionPlayerUi extends PlayerUi
             return;
         }
 
-        if (sessionConnector == null) {
-            // sessionConnector will be null after destroyPlayer is called
+        if (!mediaSession.isActive()) {
+            // mediaSession will be inactive after destroyPlayer is called
             return;
         }
 

app/src/main/java/org/schabi/newpipe/player/playqueue/AbstractInfoPlayQueue.java

@@ -28,13 +28,17 @@ abstract class AbstractInfoPlayQueue<T extends ListInfo<? extends InfoItem>>
     private transient Disposable fetchReactor;
 
     protected AbstractInfoPlayQueue(final T info) {
+        this(info, 0);
+    }
+
+    protected AbstractInfoPlayQueue(final T info, final int index) {
         this(info.getServiceId(), info.getUrl(), info.getNextPage(),
                 info.getRelatedItems()
                         .stream()
                         .filter(StreamInfoItem.class::isInstance)
                         .map(StreamInfoItem.class::cast)
                         .collect(Collectors.toList()),
-                0);
+                index);
     }
 
     protected AbstractInfoPlayQueue(final int serviceId,

app/src/main/java/org/schabi/newpipe/player/playqueue/PlaylistPlayQueue.java

@@ -16,6 +16,10 @@ public final class PlaylistPlayQueue extends AbstractInfoPlayQueue<PlaylistInfo>
         super(info);
     }
 
+    public PlaylistPlayQueue(final PlaylistInfo info, final int index) {
+        super(info, index);
+    }
+
     public PlaylistPlayQueue(final int serviceId,
                              final String url,
                              final Page nextPage,

app/src/main/java/org/schabi/newpipe/player/ui/PopupPlayerUi.java

@@ -382,7 +382,7 @@ public final class PopupPlayerUi extends VideoPlayerUi {
                     private void end() {
                         windowManager.removeView(closeOverlayBinding.getRoot());
                         closeOverlayBinding = null;
-                        player.getService().stopService();
+                        player.getService().destroyPlayerAndStopService();
                     }
                 }).start();
     }

app/src/main/java/org/schabi/newpipe/util/NavigationHelper.java

@@ -96,6 +96,7 @@ public final class NavigationHelper {
         }
         intent.putExtra(Player.PLAYER_TYPE, PlayerType.MAIN.valueForIntent());
         intent.putExtra(Player.RESUME_PLAYBACK, resumePlayback);
+        intent.putExtra(PlayerService.SHOULD_START_FOREGROUND_EXTRA, true);
 
         return intent;
     }

app/src/main/res/drawable/ic_bookmark_white.xml

@@ -0,0 +1,10 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:tint="@color/white"
+    android:viewportWidth="24"
+    android:viewportHeight="24">
+    <path
+        android:fillColor="#FF000000"
+        android:pathData="M17,3H7c-1.1,0 -1.99,0.9 -1.99,2L5,21l7,-3 7,3V5c0,-1.1 -0.9,-2 -2,-2z" />
+</vector>

app/src/main/res/drawable/ic_history_white.xml

@@ -0,0 +1,10 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:tint="@color/white"
+    android:viewportWidth="24"
+    android:viewportHeight="24">
+    <path
+        android:fillColor="#FF000000"
+        android:pathData="M13,3c-4.97,0 -9,4.03 -9,9L1,12l3.89,3.89 0.07,0.14L9,12L6,12c0,-3.87 3.13,-7 7,-7s7,3.13 7,7 -3.13,7 -7,7c-1.93,0 -3.68,-0.79 -4.94,-2.06l-1.42,1.42C8.27,19.99 10.51,21 13,21c4.97,0 9,-4.03 9,-9s-4.03,-9 -9,-9zM12,8v5l4.28,2.54 0.72,-1.21 -3.5,-2.08L13.5,8L12,8z" />
+</vector>

app/src/main/res/values/strings.xml

@@ -33,6 +33,7 @@
     <string name="show_info">Show info</string>
     <string name="tab_subscriptions">Subscriptions</string>
     <string name="tab_bookmarks">Bookmarked Playlists</string>
+    <string name="tab_bookmarks_short">Playlists</string>
     <string name="tab_choose">Choose Tab</string>
     <string name="controls_background_title">Background</string>
     <string name="controls_popup_title">Popup</string>

app/src/main/res/xml/automotive_app_desc.xml

@@ -0,0 +1,3 @@
+<automotiveApp>
+    <uses name="media" />
+</automotiveApp>