Add track selection option to use accessiblity captioning manager settings

This option allows to set the preferred text language and role flags based
on the user's accessiblity captioning settings.

Issue:#5749
PiperOrigin-RevId: 270233205

RELEASENOTES.md

@@ -36,6 +36,11 @@
 * Set `compileSdkVersion` to 29 to use Android Q APIs.
 * Add `enable` and `disable` methods to `MediaSource` to improve resource
   management in playlists.
+* Text selection logic:
+  * Allow to set preferred role flags using
+    `DefaultTrackSelector.ParametersBuilder.setPreferredTextRoleFlags`.
+  * Default text language and role flags to accessibility captioning settings
+    ([#5749](https://github.com/google/ExoPlayer/issues/5749)).
 * Remove `AnalyticsCollector.Factory`. Instances can be created directly and
   the `Player` set later using `AnalyticsCollector.setPlayer`.
 * Replace `ExoPlayerFactory` by `SimpleExoPlayer.Builder` and

library/core/src/main/java/com/google/android/exoplayer2/trackselection/DefaultTrackSelector.java

@@ -474,6 +474,13 @@ public class DefaultTrackSelector extends MappingTrackSelector {
 
     // Text
 
+    @Override
+    public ParametersBuilder setPreferredTextLanguageAndRoleFlagsToCaptioningManagerSettings(
+        Context context) {
+      super.setPreferredTextLanguageAndRoleFlagsToCaptioningManagerSettings(context);
+      return this;
+    }
+
     @Override
     public ParametersBuilder setPreferredTextLanguage(@Nullable String preferredTextLanguage) {
       super.setPreferredTextLanguage(preferredTextLanguage);
@@ -499,6 +506,7 @@ public class DefaultTrackSelector extends MappingTrackSelector {
       super.setDisabledTextTrackSelectionFlags(disabledTextTrackSelectionFlags);
       return this;
     }
+
     // General
 
     /**
@@ -757,6 +765,10 @@ public class DefaultTrackSelector extends MappingTrackSelector {
      * <ul>
      *   <li>{@link ParametersBuilder#setViewportSizeToPhysicalDisplaySize(Context, boolean)
      *       Viewport constraints} configured for the primary display.
+     *   <li>{@link
+     *       ParametersBuilder#setPreferredTextLanguageAndRoleFlagsToCaptioningManagerSettings(Context)
+     *       Preferred text language and role flags} configured to the accessibility settings of
+     *       {@link android.view.accessibility.CaptioningManager}.
      * </ul>
      */
     public static final Parameters DEFAULT_WITHOUT_CONTEXT = new Parameters();
@@ -778,6 +790,7 @@ public class DefaultTrackSelector extends MappingTrackSelector {
       return DEFAULT_WITHOUT_CONTEXT
           .buildUpon()
           .setViewportSizeToPhysicalDisplaySize(context, /* viewportOrientationMayChange= */ true)
+          .setPreferredTextLanguageAndRoleFlagsToCaptioningManagerSettings(context)
           .build();
     }
 
@@ -932,7 +945,7 @@ public class DefaultTrackSelector extends MappingTrackSelector {
           /* viewportHeight= */ Integer.MAX_VALUE,
           /* viewportOrientationMayChange= */ true,
           // Audio
-          TrackSelectionParameters.DEFAULT.preferredAudioLanguage,
+          TrackSelectionParameters.DEFAULT_WITHOUT_CONTEXT.preferredAudioLanguage,
           /* maxAudioChannelCount= */ Integer.MAX_VALUE,
           /* maxAudioBitrate= */ Integer.MAX_VALUE,
           /* exceedAudioConstraintsIfNecessary= */ true,
@@ -940,10 +953,10 @@ public class DefaultTrackSelector extends MappingTrackSelector {
           /* allowAudioMixedSampleRateAdaptiveness= */ false,
           /* allowAudioMixedChannelCountAdaptiveness= */ false,
           // Text
-          TrackSelectionParameters.DEFAULT.preferredTextLanguage,
+          TrackSelectionParameters.DEFAULT_WITHOUT_CONTEXT.preferredTextLanguage,
-          TrackSelectionParameters.DEFAULT.preferredTextRoleFlags,
+          TrackSelectionParameters.DEFAULT_WITHOUT_CONTEXT.preferredTextRoleFlags,
-          TrackSelectionParameters.DEFAULT.selectUndeterminedTextLanguage,
+          TrackSelectionParameters.DEFAULT_WITHOUT_CONTEXT.selectUndeterminedTextLanguage,
-          TrackSelectionParameters.DEFAULT.disabledTextTrackSelectionFlags,
+          TrackSelectionParameters.DEFAULT_WITHOUT_CONTEXT.disabledTextTrackSelectionFlags,
           // General
           /* forceLowestBitrate= */ false,
           /* forceHighestSupportedBitrate= */ false,

library/core/src/main/java/com/google/android/exoplayer2/trackselection/TrackSelectionParameters.java

@@ -15,12 +15,16 @@
  */
 package com.google.android.exoplayer2.trackselection;
 
+import android.annotation.TargetApi;
+import android.content.Context;
 import android.os.Parcel;
 import android.os.Parcelable;
 import android.text.TextUtils;
+import android.view.accessibility.CaptioningManager;
 import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.util.Util;
+import java.util.Locale;
 
 /** Constraint parameters for track selection. */
 public class TrackSelectionParameters implements Parcelable {
@@ -37,9 +41,22 @@ public class TrackSelectionParameters implements Parcelable {
     /* package */ boolean selectUndeterminedTextLanguage;
     @C.SelectionFlags /* package */ int disabledTextTrackSelectionFlags;
 
-    /** Creates a builder with default initial values. */
+    /**
+     * Creates a builder with default initial values.
+     *
+     * @param context Any context.
+     */
+    public Builder(Context context) {
+      this(TrackSelectionParameters.getDefaults(context));
+    }
+
+    /**
+     * @deprecated {@link Context} constraints will not be set when using this constructor. Use
+     *     {@link #Builder(Context)} instead.
+     */
+    @Deprecated
     public Builder() {
-      this(DEFAULT);
+      this(DEFAULT_WITHOUT_CONTEXT);
     }
 
     /**
@@ -66,6 +83,23 @@ public class TrackSelectionParameters implements Parcelable {
       return this;
     }
 
+    /**
+     * Sets the preferred language and role flags for text tracks based on the accessibility
+     * settings of {@link CaptioningManager}.
+     *
+     * <p>Does nothing for API levels &lt; 19 or when the {@link CaptioningManager} is disabled.
+     *
+     * @param context A {@link Context}.
+     * @return This builder.
+     */
+    public Builder setPreferredTextLanguageAndRoleFlagsToCaptioningManagerSettings(
+        Context context) {
+      if (Util.SDK_INT >= 19) {
+        setPreferredTextLanguageAndRoleFlagsToCaptioningManagerSettingsV19(context);
+      }
+      return this;
+    }
+
     /**
      * Sets the preferred language for text tracks.
      *
@@ -127,10 +161,52 @@ public class TrackSelectionParameters implements Parcelable {
           selectUndeterminedTextLanguage,
           disabledTextTrackSelectionFlags);
     }
+
+    @TargetApi(19)
+    private void setPreferredTextLanguageAndRoleFlagsToCaptioningManagerSettingsV19(
+        Context context) {
+      CaptioningManager captioningManager =
+          (CaptioningManager) context.getSystemService(Context.CAPTIONING_SERVICE);
+      if (captioningManager == null || !captioningManager.isEnabled()) {
+        return;
+      }
+      preferredTextRoleFlags = C.ROLE_FLAG_CAPTION | C.ROLE_FLAG_DESCRIBES_MUSIC_AND_SOUND;
+      Locale preferredLocale = captioningManager.getLocale();
+      if (preferredLocale != null) {
+        preferredTextLanguage = Util.getLocaleLanguageTag(preferredLocale);
+      }
+    }
   }
 
-  /** An instance with default values. */
+  /**
-  public static final TrackSelectionParameters DEFAULT = new TrackSelectionParameters();
+   * An instance with default values, except those obtained from the {@link Context}.
+   *
+   * <p>If possible, use {@link #getDefaults(Context)} instead.
+   *
+   * <p>This instance will not have the following settings:
+   *
+   * <ul>
+   *   <li>{@link Builder#setPreferredTextLanguageAndRoleFlagsToCaptioningManagerSettings(Context)
+   *       Preferred text language and role flags} configured to the accessibility settings of
+   *       {@link CaptioningManager}.
+   * </ul>
+   */
+  public static final TrackSelectionParameters DEFAULT_WITHOUT_CONTEXT =
+      new TrackSelectionParameters();
+
+  /**
+   * @deprecated This instance is not configured using {@link Context} constraints. Use {@link
+   *     #getDefaults(Context)} instead.
+   */
+  @Deprecated public static final TrackSelectionParameters DEFAULT = new TrackSelectionParameters();
+
+  /** Returns an instance configured with default values. */
+  public static TrackSelectionParameters getDefaults(Context context) {
+    return DEFAULT_WITHOUT_CONTEXT
+        .buildUpon()
+        .setPreferredTextLanguageAndRoleFlagsToCaptioningManagerSettings(context)
+        .build();
+  }
 
   /**
    * The preferred language for audio and forced text tracks as an IETF BCP 47 conformant tag.
@@ -140,12 +216,15 @@ public class TrackSelectionParameters implements Parcelable {
   @Nullable public final String preferredAudioLanguage;
   /**
    * The preferred language for text tracks as an IETF BCP 47 conformant tag. {@code null} selects
-   * the default track if there is one, or no track otherwise. The default value is {@code null}.
+   * the default track if there is one, or no track otherwise. The default value is {@code null}, or
+   * the language of the accessibility {@link CaptioningManager} if enabled.
    */
   @Nullable public final String preferredTextLanguage;
   /**
    * The preferred {@link C.RoleFlags} for text tracks. {@code 0} selects the default track if there
-   * is one, or no track otherwise. The default value is {@code 0}.
+   * is one, or no track otherwise. The default value is {@code 0}, or {@link C#ROLE_FLAG_SUBTITLE}
+   * | {@link C#ROLE_FLAG_DESCRIBES_MUSIC_AND_SOUND} if the accessibility {@link CaptioningManager}
+   * is enabled.
    */
   @C.RoleFlags public final int preferredTextRoleFlags;
   /**

library/core/src/main/java/com/google/android/exoplayer2/util/Util.java

@@ -459,6 +459,20 @@ public final class Util {
     parcel.writeInt(value ? 1 : 0);
   }
 
+  /**
+   * Returns the language tag for a {@link Locale}.
+   *
+   * <p>For API levels &ge; 21, this tag is IETF BCP 47 compliant. Use {@link
+   * #normalizeLanguageCode(String)} to retrieve a normalized IETF BCP 47 language tag for all API
+   * levels if needed.
+   *
+   * @param locale A {@link Locale}.
+   * @return The language tag.
+   */
+  public static String getLocaleLanguageTag(Locale locale) {
+    return SDK_INT >= 21 ? getLocaleLanguageTagV21(locale) : locale.toString();
+  }
+
   /**
    * Returns a normalized IETF BCP 47 language tag for {@code language}.
    *
@@ -1963,7 +1977,7 @@ public final class Util {
     Configuration config = Resources.getSystem().getConfiguration();
     return SDK_INT >= 24
         ? getSystemLocalesV24(config)
-        : SDK_INT >= 21 ? getSystemLocaleV21(config) : new String[] {config.locale.toString()};
+        : new String[] {getLocaleLanguageTag(config.locale)};
   }
 
   @TargetApi(24)
@@ -1972,8 +1986,8 @@ public final class Util {
   }
 
   @TargetApi(21)
-  private static String[] getSystemLocaleV21(Configuration config) {
+  private static String getLocaleLanguageTagV21(Locale locale) {
-    return new String[] {config.locale.toLanguageTag()};
+    return locale.toLanguageTag();
   }
 
   @TargetApi(21)