-Moved caption extraction and menu building into exoplayer track changing callback.

-Updated extractor dependency.

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

@@ -676,7 +676,7 @@ public final class PopupVideoPlayer extends Service {
 
         /*package-private*/ void enableVideoRenderer(final boolean enable) {
             final int videoRendererIndex = getRendererIndex(C.TRACK_TYPE_VIDEO);
-            if (trackSelector != null && videoRendererIndex != -1) {
+            if (trackSelector != null && videoRendererIndex != RENDERER_UNAVAILABLE) {
                 trackSelector.setRendererDisabled(videoRendererIndex, !enable);
             }
         }

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

@@ -53,6 +53,7 @@ import com.google.android.exoplayer2.SimpleExoPlayer;
 import com.google.android.exoplayer2.source.MediaSource;
 import com.google.android.exoplayer2.source.MergingMediaSource;
 import com.google.android.exoplayer2.source.SingleSampleMediaSource;
+import com.google.android.exoplayer2.source.TrackGroup;
 import com.google.android.exoplayer2.source.TrackGroupArray;
 import com.google.android.exoplayer2.trackselection.TrackSelectionArray;
 import com.google.android.exoplayer2.ui.AspectRatioFrameLayout;
@@ -98,6 +99,7 @@ public abstract class VideoPlayer extends BasePlayer
     // Player
     //////////////////////////////////////////////////////////////////////////*/
 
+    protected static final int RENDERER_UNAVAILABLE = -1;
     public static final int DEFAULT_CONTROLS_HIDE_TIME = 2000;  // 2 Seconds
 
     private ArrayList<VideoStream> availableStreams;
@@ -105,8 +107,6 @@ public abstract class VideoPlayer extends BasePlayer
 
     protected String playbackQuality;
 
-    private List<Subtitles> availableCaptions;
-
     protected boolean wasPlaying = false;
 
     /*//////////////////////////////////////////////////////////////////////////
@@ -271,35 +271,32 @@ public abstract class VideoPlayer extends BasePlayer
         playbackSpeedPopupMenu.setOnDismissListener(this);
     }
 
-    private void buildCaptionMenu() {
+    private void buildCaptionMenu(final List<String> availableLanguages) {
         if (captionPopupMenu == null) return;
         captionPopupMenu.getMenu().removeGroup(captionPopupMenuGroupId);
 
-        if (availableCaptions == null || trackSelector == null) return;
-
         // Add option for turning off caption
         MenuItem captionOffItem = captionPopupMenu.getMenu().add(captionPopupMenuGroupId,
                 0, Menu.NONE, R.string.caption_none);
         captionOffItem.setOnMenuItemClickListener(menuItem -> {
             final int textRendererIndex = getRendererIndex(C.TRACK_TYPE_TEXT);
-            if (trackSelector != null && textRendererIndex != -1) {
+            if (trackSelector != null && textRendererIndex != RENDERER_UNAVAILABLE) {
                 trackSelector.setRendererDisabled(textRendererIndex, true);
             }
             return true;
         });
 
         // Add all available captions
-        for (int i = 0; i < availableCaptions.size(); i++) {
+        for (int i = 0; i < availableLanguages.size(); i++) {
-            final Subtitles subtitles = availableCaptions.get(i);
+            final String captionLanguage = availableLanguages.get(i);
-            final String captionLanguage = PlayerHelper.captionLanguageOf(subtitles);
             MenuItem captionItem = captionPopupMenu.getMenu().add(captionPopupMenuGroupId,
                     i + 1, Menu.NONE, captionLanguage);
             captionItem.setOnMenuItemClickListener(menuItem -> {
                 final int textRendererIndex = getRendererIndex(C.TRACK_TYPE_TEXT);
-                if (trackSelector != null && textRendererIndex != -1) {
+                if (trackSelector != null && textRendererIndex != RENDERER_UNAVAILABLE) {
-                    trackSelector.setRendererDisabled(textRendererIndex, false);
                     trackSelector.setParameters(trackSelector.getParameters()
                             .withPreferredTextLanguage(captionLanguage));
+                    trackSelector.setRendererDisabled(textRendererIndex, false);
                 }
                 return true;
             });
@@ -319,7 +316,6 @@ public abstract class VideoPlayer extends BasePlayer
         super.sync(item, info);
         qualityTextView.setVisibility(View.GONE);
         playbackSpeedTextView.setVisibility(View.GONE);
-        captionTextView.setVisibility(View.GONE);
 
         if (info != null) {
             final List<VideoStream> videos = ListHelper.getSortedStreamVideosList(context,
@@ -331,14 +327,10 @@ public abstract class VideoPlayer extends BasePlayer
                 selectedStreamIndex = getOverrideResolutionIndex(videos, getPlaybackQuality());
             }
 
-            availableCaptions = info.getSubtitles();
-
             buildQualityMenu();
             buildPlaybackSpeedMenu();
-            buildCaptionMenu();
             qualityTextView.setVisibility(View.VISIBLE);
             playbackSpeedTextView.setVisibility(View.VISIBLE);
-            captionTextView.setVisibility(availableCaptions.isEmpty() ? View.GONE : View.VISIBLE);
         }
     }
 
@@ -469,17 +461,7 @@ public abstract class VideoPlayer extends BasePlayer
     @Override
     public void onTracksChanged(TrackGroupArray trackGroups, TrackSelectionArray trackSelections) {
         super.onTracksChanged(trackGroups, trackSelections);
-        if (captionTextView == null) return;
+        onTextTrackUpdate();
-
-        if (trackSelector == null) {
-            captionTextView.setVisibility(View.GONE);
-        } else if (trackSelector.getRendererDisabled(getRendererIndex(C.TRACK_TYPE_TEXT)) ||
-                trackSelector.getParameters().preferredTextLanguage == null) {
-            captionTextView.setText(R.string.caption_none);
-        } else {
-            final String preferredLanguage = trackSelector.getParameters().preferredTextLanguage;
-            captionTextView.setText(preferredLanguage);
-        }
     }
 
     @Override
@@ -495,6 +477,55 @@ public abstract class VideoPlayer extends BasePlayer
         animateView(surfaceForeground, false, 100);
     }
 
+    /*//////////////////////////////////////////////////////////////////////////
+    // ExoPlayer Track Updates
+    //////////////////////////////////////////////////////////////////////////*/
+
+    private void onTextTrackUpdate() {
+        final int textRenderer = getRendererIndex(C.TRACK_TYPE_TEXT);
+
+        if (captionTextView == null) return;
+        if (trackSelector == null || trackSelector.getCurrentMappedTrackInfo() == null ||
+                textRenderer == RENDERER_UNAVAILABLE) {
+            captionTextView.setVisibility(View.GONE);
+            return;
+        }
+
+        final TrackGroupArray textTracks = trackSelector.getCurrentMappedTrackInfo()
+                .getTrackGroups(textRenderer);
+
+        // Extract all loaded languages
+        List<String> availableLanguages = new ArrayList<>(textTracks.length);
+        for (int i = 0; i < textTracks.length; i++) {
+            final TrackGroup textTrack = textTracks.get(i);
+            if (textTrack.length > 0 && textTrack.getFormat(0) != null) {
+                availableLanguages.add(textTrack.getFormat(0).language);
+            }
+        }
+
+        // Normalize mismatching language strings
+        final String preferredLanguage = trackSelector.getParameters().preferredTextLanguage;
+        // Because ExoPlayer normalizes the preferred language string but not the text track
+        // language strings, some preferred language string will have the language name in lowercase
+        String formattedPreferredLanguage = null;
+        if (preferredLanguage != null) {
+            for (final String language : availableLanguages) {
+                if (language.compareToIgnoreCase(preferredLanguage) == 0)
+                    formattedPreferredLanguage = language;
+            }
+        }
+
+        // Build UI
+        buildCaptionMenu(availableLanguages);
+        if (trackSelector.getRendererDisabled(textRenderer) || formattedPreferredLanguage == null ||
+                !availableLanguages.contains(formattedPreferredLanguage)) {
+            captionTextView.setText(R.string.caption_none);
+        } else {
+            captionTextView.setText(formattedPreferredLanguage);
+        }
+        captionTextView.setVisibility(availableLanguages.isEmpty() ? View.GONE : View.VISIBLE);
+    }
+
     /*//////////////////////////////////////////////////////////////////////////
     // General Player
     //////////////////////////////////////////////////////////////////////////*/
@@ -688,7 +719,7 @@ public abstract class VideoPlayer extends BasePlayer
     //////////////////////////////////////////////////////////////////////////*/
 
     public int getRendererIndex(final int trackIndex) {
-        if (simpleExoPlayer == null) return -1;
+        if (simpleExoPlayer == null) return RENDERER_UNAVAILABLE;
 
         for (int t = 0; t < simpleExoPlayer.getRendererCount(); t++) {
             if (simpleExoPlayer.getRendererType(t) == trackIndex) {
@@ -696,7 +727,7 @@ public abstract class VideoPlayer extends BasePlayer
             }
         }
 
-        return -1;
+        return RENDERER_UNAVAILABLE;
     }
 
     public boolean isControlsVisible() {