chore: support preferred languages on HLS redundant stream. (#14)

Author: guoen21

demos/main/src/main/assets/media.exolist.json

@@ -228,6 +228,13 @@
         "name": "WWE live, wwe",
         "uri": "https://dummy.imggaming.com/video?id=111449&live=true&dash=&realm=dce.wwe&usr=&pwd="
       },
+      {
+        "name": "WWE vod, wwe",
+        "uri": "https://dummy.imggaming.com/video?id=530182&live=&dash=&realm=dce.wwe&usr=&pwd=",
+        "subtitle_uri": "https://dve-subtitles.imggaming.com/530182/741299/vtt/subtitle-en-US-199647-1697490152197.vtt",
+        "subtitle_mime_type": "text/vtt",
+        "subtitle_language": "en"
+      },
       {
         "name": "450830 DRM, adjara",
         "uri": "https://dummy.imggaming.com/video?id=450830&live=&dash=true&realm=dce.adjara&usr=&pwd="

demos/main/src/main/java/androidx/media3/demo/main/SampleChooserActivity.java

@@ -280,6 +280,11 @@ public boolean onChildClick(
                 List<MediaItem> mediaItems = playlistHolder.mediaItems;
                 if (result != null && result.localConfiguration != null) {
                   Log.i(TAG, "fetch video from backend - " + originUri.getQuery() + " >> " + result.localConfiguration.uri);
+                  if (playlistHolder.mediaItems.get(0).localConfiguration.subtitleConfigurations != null) {
+                    result = result.buildUpon()
+                        .setSubtitleConfigurations(playlistHolder.mediaItems.get(0).localConfiguration.subtitleConfigurations)
+                        .build();
+                  }
                   mediaItems = Collections.singletonList(result);
                 }
                 IntentUtil.addToIntent(mediaItems, intent);

libraries/exoplayer/src/main/java/androidx/media3/exoplayer/endeavor/TrackCollector.java

@@ -11,9 +11,11 @@
 import androidx.media3.common.endeavor.WebUtil;
 import androidx.media3.common.util.Log;
 import androidx.media3.exoplayer.source.TrackGroupArray;
+import androidx.media3.exoplayer.trackselection.DefaultTrackSelector;
 import androidx.media3.exoplayer.trackselection.ExoTrackSelection;
 import androidx.media3.exoplayer.trackselection.MappingTrackSelector;
 import androidx.media3.exoplayer.trackselection.TrackSelector;
+import com.google.common.collect.ImmutableList;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.Map;
@@ -43,6 +45,7 @@ public TrackCollector(TrackSelector callback) {
   // May update status for the blacklistUntilTimes, videoTrackSelection, preferredAudioName and so on.
   public void onMappedTrackInfoChanged(
       MappingTrackSelector.MappedTrackInfo mappedTrackInfo,
+      DefaultTrackSelector.Parameters parameters,
       ExoTrackSelection.Definition[] overrideDefinitions) {
     this.noGroupConstraint = true;
     this.videoUseFixedSelection = false;
@@ -72,25 +75,22 @@ public void onMappedTrackInfoChanged(
           Format format = overrideDefinitions[i].group.getFormat(overrideDefinitions[i].tracks[0]);
           preferredAudioName = getFormatName(format);
         } else if (preferredAudioName == null) {
-          preferredAudioName = "";
-          for (int j = 0; j < trackGroups.length; j++) {
-            TrackGroup track = trackGroups.get(j);
-            for (int k = 0; k < track.length; k++) {
-              Format format = track.getFormat(k);
-              if ((format.selectionFlags & C.SELECTION_FLAG_DEFAULT) != 0) {
-                preferredAudioName = getFormatName(format);
-                break;
-              }
-            }
+          preferredAudioName = getParametersPreferred(trackGroups, parameters.preferredAudioLanguages);
+          if (preferredAudioName == null) {
+            preferredAudioName = getDefaultPreferred(trackGroups);
           }
         }
       } else if (C.TRACK_TYPE_TEXT == mappedTrackInfo.getRendererType(i)) {
         // Init the preferred text name.
         if (overrideDefinitions[i] != null) {
           Format format = overrideDefinitions[i].group.getFormat(overrideDefinitions[i].tracks[0]);
           preferredTextName = getFormatName(format);
-        } else {
-          preferredTextName = "";
+        } else if (preferredTextName == null) {
+          TrackGroupArray trackGroups = mappedTrackInfo.getTrackGroups(i);
+          preferredTextName = getParametersPreferred(trackGroups, parameters.preferredTextLanguages);
+          if (preferredTextName == null) {
+            preferredTextName = "";
+          }
         }
       }
     }
@@ -305,6 +305,55 @@ private TrackGroupArray getTrackGroups(int trackType) {
     return new TrackGroupArray();
   }
 
+  private String getParametersPreferred(
+      TrackGroupArray trackGroups,
+      ImmutableList<String> preferredLanguages) {
+    if (preferredLanguages.size() == 0) {
+      return null;
+    }
+
+    int bestLanguageScore = 0;
+    int bestLanguageIndex = Integer.MAX_VALUE;
+    String preferredName = null;
+    for (int i = 0; i < trackGroups.length; i++) {
+      TrackGroup trackGroup = trackGroups.get(i);
+      if (trackGroup.length == 0) {
+        continue;
+      }
+      Format format = trackGroup.getFormat(0);
+      for (int j = 0; j < preferredLanguages.size(); j++) {
+        int score = DefaultTrackSelector.getFormatLanguageScore(
+                format,
+                preferredLanguages.get(j),
+                /* allowUndeterminedFormatLanguage= */ false);
+        if (score > 0) {
+          if (j < bestLanguageIndex || (j == bestLanguageIndex && score > bestLanguageScore)) {
+            bestLanguageIndex = j;
+            bestLanguageScore = score;
+            preferredName = getFormatName(format);
+          }
+          break;
+        }
+      }
+    }
+    return preferredName;
+  }
+
+  private String getDefaultPreferred(TrackGroupArray trackGroups) {
+    String preferredName = "";
+    for (int i = 0; i < trackGroups.length; i++) {
+      TrackGroup trackGroup = trackGroups.get(i);
+      for (int j = 0; j < trackGroup.length; j++) {
+        Format format = trackGroup.getFormat(j);
+        if ((format.selectionFlags & C.SELECTION_FLAG_DEFAULT) != 0) {
+          preferredName = getFormatName(format);
+          break;
+        }
+      }
+    }
+    return preferredName;
+  }
+
   private static int getMetadataEntrySize(Format format) {
     return (format == null || format.metadata == null ? 0 : format.metadata.length());
   }

libraries/exoplayer/src/main/java/androidx/media3/exoplayer/trackselection/DefaultTrackSelector.java

@@ -2388,7 +2388,7 @@ private void setParametersInternal(Parameters parameters) {
     }
     int rendererCount = mappedTrackInfo.getRendererCount();
     // May update status of track collector for the preferredAudioName, blacklistUntilTimes and so on.
-    trackCollector.onMappedTrackInfoChanged(mappedTrackInfo, getOverrideDefinitions(mappedTrackInfo, parameters));
+    trackCollector.onMappedTrackInfoChanged(mappedTrackInfo, parameters, getOverrideDefinitions(mappedTrackInfo, parameters));
     ExoTrackSelection.@NullableType Definition[] definitions =
         selectAllTracks(
             mappedTrackInfo,
@@ -3161,7 +3161,7 @@ protected static String normalizeUndeterminedLanguageToNull(@Nullable String lan
    *     1 if the format language is undetermined and such a match is allowed, and a score of 0 if
    *     the languages don't match at all.
    */
-  protected static int getFormatLanguageScore(
+  public static int getFormatLanguageScore(
       Format format, @Nullable String language, boolean allowUndeterminedFormatLanguage) {
     if (!TextUtils.isEmpty(language) && language.equals(format.language)) {
       // Full literal match of non-empty languages, including matches of an explicit "und" query.