-Improved DeferredMediaSource to build source on IO thread.

-Improved exception handling for player.

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

@@ -401,11 +401,18 @@ public final class BackgroundPlayer extends Service {
         }
 
         @Override
-        public void onError(Exception exception) {
+        public void onRecoverableError(Exception exception) {
             exception.printStackTrace();
             Toast.makeText(context, "Failed to play this audio", Toast.LENGTH_SHORT).show();
         }
 
+        @Override
+        public void onUnrecoverableError(Exception exception) {
+            exception.printStackTrace();
+            Toast.makeText(context, "Unexpected error occurred", Toast.LENGTH_SHORT).show();
+            shutdown();
+        }
+
         /*//////////////////////////////////////////////////////////////////////////
         // ExoPlayer Listener
         //////////////////////////////////////////////////////////////////////////*/

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

@@ -661,25 +661,48 @@ public abstract class BasePlayer implements Player.EventListener,
         }
     }
 
+    /**
+     * Processes the exceptions produced by {@link com.google.android.exoplayer2.ExoPlayer ExoPlayer}.
+     * There are multiple types of errors: <br><br>
+     *
+     * {@link ExoPlaybackException#TYPE_SOURCE TYPE_SOURCE}: <br><br>
+     * If the current {@link com.google.android.exoplayer2.Timeline.Window window} has
+     * duration and position greater than 0, then we know the current window is working correctly
+     * and the error is produced by transitioning into a bad window, therefore we simply increment
+     * the current index. Otherwise, we report an error to the play queue.
+     *
+     * This is done because ExoPlayer reports the source exceptions before window is
+     * transitioned on seamless playback.
+     *
+     * Because player error causes ExoPlayer to go back to {@link Player#STATE_IDLE STATE_IDLE},
+     * we reset and prepare the media source again to resume playback.<br><br>
+     *
+     * {@link ExoPlaybackException#TYPE_RENDERER TYPE_RENDERER} and
+     * {@link ExoPlaybackException#TYPE_UNEXPECTED TYPE_UNEXPECTED}: <br><br>
+     * If renderer failed or unexpected exceptions occurred, treat the error as unrecoverable.
+     *
+     * @see Player.EventListener#onPlayerError(ExoPlaybackException)
+     *  */
     @Override
     public void onPlayerError(ExoPlaybackException error) {
         if (DEBUG) Log.d(TAG, "onPlayerError() called with: error = [" + error + "]");
 
-        // If the current window is seekable, then the error is produced by transitioning into
+        switch (error.type) {
-        // bad window, therefore we simply increment the current index.
+            case ExoPlaybackException.TYPE_SOURCE:
-        // This is done because ExoPlayer reports the exception before window is
+                if (simpleExoPlayer.getDuration() < 0 || simpleExoPlayer.getCurrentPosition() < 0) {
-        // transitioned due to seamless playback.
+                    playQueue.error();
-        if (!simpleExoPlayer.isCurrentWindowSeekable()) {
+                    onRecoverableError(error);
-            playQueue.error();
+                } else {
-            onError(error);
+                    playQueue.offsetIndex(+1);
-        } else {
+                }
-            playQueue.offsetIndex(+1);
-        }
 
-        // Player error causes ExoPlayer to go back to IDLE state, which requires resetting
+                playbackManager.reset();
-        // preparing a new media source.
+                playbackManager.load();
-        playbackManager.reset();
+                break;
-        playbackManager.load();
+            default:
+                onUnrecoverableError(error);
+                break;
+        }
     }
 
     @Override
@@ -752,7 +775,9 @@ public abstract class BasePlayer implements Player.EventListener,
     // General Player
     //////////////////////////////////////////////////////////////////////////*/
 
-    public abstract void onError(Exception exception);
+    public abstract void onRecoverableError(Exception exception);
+
+    public abstract void onUnrecoverableError(Exception exception);
 
     public void onPrepared(boolean playWhenReady) {
         if (DEBUG) Log.d(TAG, "onPrepared() called with: playWhenReady = [" + playWhenReady + "]");

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

@@ -352,11 +352,18 @@ public final class MainVideoPlayer extends Activity {
         }
 
         @Override
-        public void onError(Exception exception) {
+        public void onRecoverableError(Exception exception) {
             exception.printStackTrace();
             Toast.makeText(context, "Failed to play this video", Toast.LENGTH_SHORT).show();
         }
 
+        @Override
+        public void onUnrecoverableError(Exception exception) {
+            exception.printStackTrace();
+            Toast.makeText(context, "Unexpected error occurred", Toast.LENGTH_SHORT).show();
+            shutdown();
+        }
+
         /*//////////////////////////////////////////////////////////////////////////
         // States
         //////////////////////////////////////////////////////////////////////////*/

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

@@ -463,11 +463,18 @@ public final class PopupVideoPlayer extends Service {
         }
 
         @Override
-        public void onError(Exception exception) {
+        public void onRecoverableError(Exception exception) {
             exception.printStackTrace();
             Toast.makeText(context, "Failed to play this video", Toast.LENGTH_SHORT).show();
         }
 
+        @Override
+        public void onUnrecoverableError(Exception exception) {
+            exception.printStackTrace();
+            Toast.makeText(context, "Unexpected error occurred", Toast.LENGTH_SHORT).show();
+            shutdown();
+        }
+
         @Override
         public void onStopTrackingTouch(SeekBar seekBar) {
             super.onStopTrackingTouch(seekBar);

app/src/main/java/org/schabi/newpipe/player/mediasource/DeferredMediaSource.java

@@ -16,6 +16,7 @@ import java.io.IOException;
 import io.reactivex.android.schedulers.AndroidSchedulers;
 import io.reactivex.disposables.Disposable;
 import io.reactivex.functions.Consumer;
+import io.reactivex.functions.Function;
 import io.reactivex.schedulers.Schedulers;
 
 /**
@@ -113,44 +114,60 @@ public final class DeferredMediaSource implements MediaSource {
 
         Log.d(TAG, "Loading: [" + stream.getTitle() + "] with url: " + stream.getUrl());
 
-        final Consumer<StreamInfo> onSuccess = new Consumer<StreamInfo>() {
+        final Function<StreamInfo, MediaSource> onReceive = new Function<StreamInfo, MediaSource>() {
             @Override
-            public void accept(StreamInfo streamInfo) throws Exception {
+            public MediaSource apply(StreamInfo streamInfo) throws Exception {
-                onStreamInfoReceived(streamInfo);
+                return onStreamInfoReceived(streamInfo);
+            }
+        };
+
+        final Consumer<MediaSource> onSuccess = new Consumer<MediaSource>() {
+            @Override
+            public void accept(MediaSource mediaSource) throws Exception {
+                onMediaSourceReceived(mediaSource);
             }
         };
 
         final Consumer<Throwable> onError = new Consumer<Throwable>() {
             @Override
             public void accept(Throwable throwable) throws Exception {
-            onStreamInfoError(throwable);
+                onStreamInfoError(throwable);
             }
         };
 
         loader = stream.getStream()
-                .subscribeOn(Schedulers.io())
+                .observeOn(Schedulers.io())
+                .map(onReceive)
                 .observeOn(AndroidSchedulers.mainThread())
                 .subscribe(onSuccess, onError);
     }
 
-    private void onStreamInfoReceived(final StreamInfo streamInfo) {
+    private MediaSource onStreamInfoReceived(final StreamInfo streamInfo) throws Exception {
+        if (callback == null) {
+            throw new Exception("No available callback for resolving stream info.");
+        }
+
+        final MediaSource mediaSource = callback.sourceOf(streamInfo);
+
+        if (mediaSource == null) {
+            throw new Exception("Unable to resolve source from stream info. URL: " + stream.getUrl() +
+                    ", audio count: " + streamInfo.audio_streams.size() +
+                    ", video count: " + streamInfo.video_only_streams.size() + streamInfo.video_streams.size());
+        }
+
+        return mediaSource;
+    }
+
+    private void onMediaSourceReceived(final MediaSource mediaSource) throws Exception {
+        if (exoPlayer == null || listener == null || mediaSource == null) {
+            throw new Exception("MediaSource loading failed. URL: " + stream.getUrl());
+        }
+
         Log.d(TAG, " Loaded: [" + stream.getTitle() + "] with url: " + stream.getUrl());
         state = STATE_LOADED;
 
-        if (exoPlayer == null || listener == null || streamInfo == null) {
+        this.mediaSource = mediaSource;
-            error = new Throwable("Stream info loading failed. URL: " + stream.getUrl());
+        this.mediaSource.prepareSource(exoPlayer, false, listener);
-            return;
-        }
-
-        mediaSource = callback.sourceOf(streamInfo);
-        if (mediaSource == null) {
-            error = new Throwable("Unable to resolve source from stream info. URL: " + stream.getUrl() +
-                    ", audio count: " + streamInfo.audio_streams.size() +
-                    ", video count: " + streamInfo.video_only_streams.size() + streamInfo.video_streams.size());
-            return;
-        }
-
-        mediaSource.prepareSource(exoPlayer, false, listener);
     }
 
     private void onStreamInfoError(final Throwable throwable) {