-Fixed Deferred Media Source not working on non-extractor (e.g. dash) sources.

-Fixed NPE when extracting streams with no audio.

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

@@ -551,6 +551,8 @@ public abstract class BasePlayer implements Player.EventListener,
     //////////////////////////////////////////////////////////////////////////*/
 
     private void refreshTimeline() {
+        playbackManager.load();
+
         final int currentSourceIndex = playbackManager.getCurrentSourceIndex();
 
         // Sanity checks
@@ -558,15 +560,6 @@ public abstract class BasePlayer implements Player.EventListener,
 
         // Check if already playing correct window
         final boolean isCurrentWindowCorrect = simpleExoPlayer.getCurrentWindowIndex() == currentSourceIndex;
-        if (isCurrentWindowCorrect && getCurrentState() == STATE_PLAYING) return;
-
-        // Check timeline is up-to-date and has window
-        if (playbackManager.expectedTimelineSize() != simpleExoPlayer.getCurrentTimeline().getWindowCount()) return;
-
-        // Check if window is ready
-        Timeline.Window window = new Timeline.Window();
-        simpleExoPlayer.getCurrentTimeline().getWindow(currentSourceIndex, window);
-        if (window.isDynamic) return;
 
         // Check if on wrong window
         if (!isCurrentWindowCorrect) {
@@ -576,14 +569,16 @@ public abstract class BasePlayer implements Player.EventListener,
         }
 
         // Check if recovering
-        if (isRecovery && queuePos == playQueue.getIndex() && isCurrentWindowCorrect) {
+        if (isCurrentWindowCorrect && isRecovery && queuePos == playQueue.getIndex()) {
-            if (DEBUG) Log.d(TAG, "Rewinding to recovery window: " + currentSourceIndex + " at: " + getTimeString((int)videoPos));
+            // todo: figure out exactly why this is the case
-            simpleExoPlayer.seekTo(videoPos);
+            /* Rounding time to nearest second as certain media cannot guarantee a sub-second seek
+             will complete and the player might get stuck in buffering state forever */
+            final long roundedPos = (videoPos / 1000) * 1000;
+
+            if (DEBUG) Log.d(TAG, "Rewinding to recovery window: " + currentSourceIndex + " at: " + getTimeString((int)roundedPos));
+            simpleExoPlayer.seekTo(roundedPos);
             isRecovery = false;
         }
-
-        // Good to go...
-        simpleExoPlayer.setPlayWhenReady(true);
     }
 
     /*//////////////////////////////////////////////////////////////////////////
@@ -628,7 +623,9 @@ public abstract class BasePlayer implements Player.EventListener,
                 isPrepared = false;
                 break;
             case Player.STATE_BUFFERING: // 2
-                if (isPrepared) changeState(STATE_BUFFERING);
+                if (isPrepared) {
+                    changeState(STATE_BUFFERING);
+                }
                 break;
             case Player.STATE_READY: //3
                 if (!isPrepared) {

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

@@ -265,9 +265,11 @@ public abstract class VideoPlayer extends BasePlayer implements SimpleExoPlayer.
         }
 
         final AudioStream audio = ListHelper.getHighestQualityAudio(info.audio_streams);
-        final Uri audioUri = Uri.parse(audio.url);
+        if (audio != null) {
-        final MediaSource audioSource = new ExtractorMediaSource(audioUri, cacheDataSourceFactory, extractorsFactory, null, null);
+            final Uri audioUri = Uri.parse(audio.url);
-        sources.add(audioSource);
+            final MediaSource audioSource = new ExtractorMediaSource(audioUri, cacheDataSourceFactory, extractorsFactory, null, null);
+            sources.add(audioSource);
+        }
 
         return new MergingMediaSource(sources.toArray(new MediaSource[sources.size()]));
     }

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

@@ -1,53 +1,107 @@
 package org.schabi.newpipe.player.mediasource;
 
-import android.os.Looper;
+import android.support.annotation.NonNull;
+import android.util.Log;
 
-import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.ExoPlayer;
 import com.google.android.exoplayer2.source.MediaPeriod;
 import com.google.android.exoplayer2.source.MediaSource;
-import com.google.android.exoplayer2.source.MergingMediaSource;
-import com.google.android.exoplayer2.source.SinglePeriodTimeline;
 import com.google.android.exoplayer2.upstream.Allocator;
 
 import org.schabi.newpipe.extractor.stream.StreamInfo;
 import org.schabi.newpipe.playlist.PlayQueueItem;
 
 import java.io.IOException;
-import java.util.List;
+
+import io.reactivex.SingleObserver;
+import io.reactivex.android.schedulers.AndroidSchedulers;
+import io.reactivex.disposables.Disposable;
+import io.reactivex.functions.Consumer;
+import io.reactivex.schedulers.Schedulers;
 
 public final class DeferredMediaSource implements MediaSource {
+    private final String TAG = "DeferredMediaSource@" + Integer.toHexString(hashCode());
+
+    private int state = -1;
+
+    public final static int STATE_INIT = 0;
+    public final static int STATE_PREPARED = 1;
+    public final static int STATE_LOADED = 2;
+    public final static int STATE_DISPOSED = 3;
 
     public interface Callback {
         MediaSource sourceOf(final StreamInfo info);
     }
 
-    final private PlayQueueItem stream;
+    private PlayQueueItem stream;
-    final private Callback callback;
+    private Callback callback;
 
-    private StreamInfo info;
     private MediaSource mediaSource;
 
-    private ExoPlayer exoPlayer;
+    private Disposable loader;
-    private boolean isTopLevel;
-    private Listener listener;
 
-    public DeferredMediaSource(final PlayQueueItem stream, final Callback callback) {
+    private ExoPlayer exoPlayer;
+    private Listener listener;
+    private Throwable error;
+
+    public DeferredMediaSource(@NonNull final PlayQueueItem stream,
+                               @NonNull final Callback callback) {
         this.stream = stream;
         this.callback = callback;
+        this.state = STATE_INIT;
     }
 
     @Override
     public void prepareSource(ExoPlayer exoPlayer, boolean isTopLevelSource, Listener listener) {
         this.exoPlayer = exoPlayer;
-        this.isTopLevel = isTopLevelSource;
         this.listener = listener;
+        this.state = STATE_PREPARED;
+    }
 
-        listener.onSourceInfoRefreshed(new SinglePeriodTimeline(C.TIME_UNSET, false), null);
+    public int state() {
+        return state;
+    }
+
+    public synchronized void load() {
+        if (state != STATE_PREPARED || stream == null || loader != null) return;
+        Log.d(TAG, "Loading: [" + stream.getTitle() + "] with url: " + stream.getUrl());
+
+        final Consumer<StreamInfo> onSuccess = new Consumer<StreamInfo>() {
+            @Override
+            public void accept(StreamInfo streamInfo) throws Exception {
+                if (exoPlayer == null && listener == null) {
+                    error = new Throwable("Stream info loading failed. URL: " + stream.getUrl());
+                } else {
+                    Log.d(TAG, " Loaded: [" + stream.getTitle() + "] with url: " + stream.getUrl());
+
+                    mediaSource = callback.sourceOf(streamInfo);
+                    mediaSource.prepareSource(exoPlayer, false, listener);
+                    state = STATE_LOADED;
+                }
+            }
+        };
+
+        final Consumer<Throwable> onError = new Consumer<Throwable>() {
+            @Override
+            public void accept(Throwable throwable) throws Exception {
+                Log.e(TAG, "Loading error:", throwable);
+                error = throwable;
+                state = STATE_LOADED;
+            }
+        };
+
+        loader = stream.getStream()
+                .subscribeOn(Schedulers.io())
+                .observeOn(AndroidSchedulers.mainThread())
+                .subscribe(onSuccess, onError);
     }
 
     @Override
     public void maybeThrowSourceInfoRefreshError() throws IOException {
+        if (error != null) {
+            throw new IOException(error);
+        }
+
         if (mediaSource != null) {
             mediaSource.maybeThrowSourceInfoRefreshError();
         }
@@ -55,28 +109,33 @@ public final class DeferredMediaSource implements MediaSource {
 
     @Override
     public MediaPeriod createPeriod(MediaPeriodId mediaPeriodId, Allocator allocator) {
-        // This must be called on a non-main thread
-        if (Looper.myLooper() == Looper.getMainLooper()) {
-            throw new UnsupportedOperationException("Source preparation is blocking, it must be run on non-UI thread.");
-        }
-
-        info = stream.getStream().blockingGet();
-
-        mediaSource = callback.sourceOf(info);
-        mediaSource.prepareSource(exoPlayer, isTopLevel, listener);
-
         return mediaSource.createPeriod(mediaPeriodId, allocator);
     }
 
     @Override
     public void releasePeriod(MediaPeriod mediaPeriod) {
-        mediaSource.releasePeriod(mediaPeriod);
+        if (mediaSource == null) {
+            Log.e(TAG, "releasePeriod() called when media source is null, memory leak may have occurred.");
+        } else {
+            mediaSource.releasePeriod(mediaPeriod);
+        }
     }
 
     @Override
     public void releaseSource() {
-        if (mediaSource != null) mediaSource.releaseSource();
+        state = STATE_DISPOSED;
-        info = null;
+
-        mediaSource = null;
+        if (mediaSource != null) {
+            mediaSource.releaseSource();
+        }
+        if (loader != null) {
+            loader.dispose();
+        }
+
+        /* Do not set mediaSource as null here as it may be called through releasePeriod */
+        stream = null;
+        callback = null;
+        exoPlayer = null;
+        listener = null;
     }
 }

app/src/main/java/org/schabi/newpipe/player/playback/MediaSourceManager.java

@@ -1,6 +1,7 @@
 package org.schabi.newpipe.player.playback;
 
 import android.support.annotation.Nullable;
+import android.util.Log;
 
 import com.google.android.exoplayer2.source.DynamicConcatenatingMediaSource;
 import com.google.android.exoplayer2.source.MediaSource;
@@ -13,16 +14,13 @@ import org.schabi.newpipe.playlist.PlayQueue;
 import org.schabi.newpipe.playlist.PlayQueueItem;
 import org.schabi.newpipe.playlist.events.PlayQueueMessage;
 import org.schabi.newpipe.playlist.events.RemoveEvent;
-import org.schabi.newpipe.playlist.events.UpdateEvent;
 
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 
-import io.reactivex.SingleObserver;
 import io.reactivex.android.schedulers.AndroidSchedulers;
 import io.reactivex.annotations.NonNull;
-import io.reactivex.disposables.CompositeDisposable;
 import io.reactivex.disposables.Disposable;
 import io.reactivex.functions.Consumer;
 
@@ -44,7 +42,6 @@ public class MediaSourceManager implements DeferredMediaSource.Callback {
 
     private Subscription playQueueReactor;
     private Disposable syncReactor;
-    private CompositeDisposable disposables;
 
     private boolean isBlocked;
 
@@ -53,8 +50,6 @@ public class MediaSourceManager implements DeferredMediaSource.Callback {
         this.playbackListener = listener;
         this.playQueue = playQueue;
 
-        this.disposables = new CompositeDisposable();
-
         this.sources = new DynamicConcatenatingMediaSource();
         this.sourceToQueueIndex = Collections.synchronizedList(new ArrayList<Integer>());
 
@@ -85,18 +80,35 @@ public class MediaSourceManager implements DeferredMediaSource.Callback {
 
     public void dispose() {
         if (playQueueReactor != null) playQueueReactor.cancel();
-        if (disposables != null) disposables.dispose();
         if (syncReactor != null) syncReactor.dispose();
         if (sources != null) sources.releaseSource();
         if (sourceToQueueIndex != null) sourceToQueueIndex.clear();
 
         playQueueReactor = null;
-        disposables = null;
         syncReactor = null;
         sources = null;
         sourceToQueueIndex = null;
     }
 
+    public void load() {
+        // The current item has higher priority
+        final int currentIndex = playQueue.getIndex();
+        final PlayQueueItem currentItem = playQueue.get(currentIndex);
+        if (currentItem == null) return;
+        load(currentItem);
+
+        // The rest are just for seamless playback
+        final int leftBound = Math.max(0, currentIndex - WINDOW_SIZE);
+        final int rightLimit = currentIndex + WINDOW_SIZE + 1;
+        final int rightBound = Math.min(playQueue.size(), rightLimit);
+        final List<PlayQueueItem> items = new ArrayList<>(playQueue.getStreams().subList(leftBound, rightBound));
+
+        final int excess = rightLimit - playQueue.size();
+        if (excess >= 0) items.addAll(playQueue.getStreams().subList(0, Math.min(playQueue.size(), excess)));
+
+        for (final PlayQueueItem item: items) load(item);
+    }
+
     /*//////////////////////////////////////////////////////////////////////////
     // Event Reactor
     //////////////////////////////////////////////////////////////////////////*/
@@ -115,30 +127,26 @@ public class MediaSourceManager implements DeferredMediaSource.Callback {
                 // why no pattern matching in Java =(
                 switch (event.type()) {
                     case APPEND:
+                        populateSources();
                         break;
                     case SELECT:
-                        if (isBlocked) break;
                         if (isCurrentIndexLoaded()) {
                             sync();
-                        } else {
-                            tryBlock();
-                            resetSources();
                         }
                         break;
                     case REMOVE:
                         final RemoveEvent removeEvent = (RemoveEvent) event;
                         if (!removeEvent.isCurrent()) {
                             remove(removeEvent.index());
-                        } else {
+                            break;
-                            tryBlock();
-                            resetSources();
                         }
-                        break;
                     case INIT:
                     case UPDATE:
                     case REORDER:
                         tryBlock();
                         resetSources();
+                        populateSources();
+                        if (tryUnblock()) sync();
                         break;
                     default:
                         break;
@@ -204,31 +212,46 @@ public class MediaSourceManager implements DeferredMediaSource.Callback {
             }
         };
 
-        currentItem.getStream().subscribe(syncPlayback);
+        final Consumer<Throwable> onError = new Consumer<Throwable>() {
+            @Override
+            public void accept(Throwable throwable) throws Exception {
+                Log.e(TAG, "Sync error:", throwable);
+            }
+        };
+
+        currentItem.getStream().subscribe(syncPlayback, onError);
     }
 
-    private void load() {
+    private void load(@Nullable final PlayQueueItem item) {
-        for (final PlayQueueItem item : playQueue.getStreams()) {
+        if (item == null) return;
-            insert(playQueue.indexOf(item), new DeferredMediaSource(item, this));
+
-            if (tryUnblock()) sync();
+        final int index = playQueue.indexOf(item);
-        }
+        if (index > sources.getSize() - 1) return;
+
+        final DeferredMediaSource mediaSource = (DeferredMediaSource) sources.getMediaSource(playQueue.indexOf(item));
+        if (mediaSource.state() == DeferredMediaSource.STATE_PREPARED) mediaSource.load();
     }
 
     private void resetSources() {
-        if (this.disposables != null) this.disposables.clear();
         if (this.sources != null) this.sources.releaseSource();
         if (this.sourceToQueueIndex != null) this.sourceToQueueIndex.clear();
 
         this.sources = new DynamicConcatenatingMediaSource();
     }
 
+    private void populateSources() {
+        for (final PlayQueueItem item : playQueue.getStreams()) {
+            insert(playQueue.indexOf(item), new DeferredMediaSource(item, this));
+        }
+    }
+
     /*//////////////////////////////////////////////////////////////////////////
     // Media Source List Manipulation
     //////////////////////////////////////////////////////////////////////////*/
 
     // Insert source into playlist with position in respect to the play queue
     // If the play queue index already exists, then the insert is ignored
-    private void insert(final int queueIndex, final MediaSource source) {
+    private void insert(final int queueIndex, final DeferredMediaSource source) {
         if (queueIndex < 0) return;
 
         int pos = Collections.binarySearch(sourceToQueueIndex, queueIndex);

app/src/main/java/org/schabi/newpipe/playlist/PlayQueue.java

@@ -15,6 +15,7 @@ import org.schabi.newpipe.playlist.events.UpdateEvent;
 
 import java.io.Serializable;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
@@ -147,9 +148,9 @@ public abstract class PlayQueue implements Serializable {
         broadcast(new UpdateEvent(index));
     }
 
-    protected synchronized void append(final PlayQueueItem item) {
+    protected synchronized void append(final PlayQueueItem... items) {
-        streams.add(item);
+        streams.addAll(Arrays.asList(items));
-        broadcast(new AppendEvent(1));
+        broadcast(new AppendEvent(items.length));
     }
 
     protected synchronized void append(final Collection<PlayQueueItem> items) {