DefaultTrackSelector: Constrain audio channel count

The track selector will select multi-channel formats when those can be
spatialized, otherwise the selector will prefer stereo/mono audio
tracks. When the device supports audio spatialization (Android 12L+),
the DefaultTrackSelector will monitor for changes in the platform
Spatializer and trigger a new track selection upon a
Spatializer change event.

Devices with a `television` UI mode are excluded from audio channel
count constraints.

#minor-release

PiperOrigin-RevId: 453957269
(cherry picked from commit 9f3c595)

library/core/src/main/java/com/google/android/exoplayer2/ExoPlayerImpl.java

@@ -369,6 +369,7 @@ public ExoPlayerImpl(ExoPlayer.Builder builder, @Nullable Player wrappingPlayer)
       deviceInfo = createDeviceInfo(streamVolumeManager);
       videoSize = VideoSize.UNKNOWN;
 
+      trackSelector.setAudioAttributes(audioAttributes);
       sendRendererMessage(TRACK_TYPE_AUDIO, MSG_SET_AUDIO_SESSION_ID, audioSessionId);
       sendRendererMessage(TRACK_TYPE_VIDEO, MSG_SET_AUDIO_SESSION_ID, audioSessionId);
       sendRendererMessage(TRACK_TYPE_AUDIO, MSG_SET_AUDIO_ATTRIBUTES, audioAttributes);
@@ -1364,6 +1365,7 @@ public void setAudioAttributes(AudioAttributes newAudioAttributes, boolean handl
     }
 
     audioFocusManager.setAudioAttributes(handleAudioFocus ? newAudioAttributes : null);
+    trackSelector.setAudioAttributes(newAudioAttributes);
     boolean playWhenReady = getPlayWhenReady();
     @AudioFocusManager.PlayerCommand
     int playerCommand = audioFocusManager.updateAudioFocus(playWhenReady, getPlaybackState());

library/core/src/main/java/com/google/android/exoplayer2/offline/DownloadHelper.java

@@ -107,13 +107,15 @@ public final class DownloadHelper {
           DefaultTrackSelector.Parameters.DEFAULT_WITHOUT_CONTEXT
               .buildUpon()
               .setForceHighestSupportedBitrate(true)
+              .setConstrainAudioChannelCountToDeviceCapabilities(false)
               .build();
 
   /** Returns the default parameters used for track selection for downloading. */
   public static DefaultTrackSelector.Parameters getDefaultTrackSelectorParameters(Context context) {
     return DefaultTrackSelector.Parameters.getDefaults(context)
         .buildUpon()
         .setForceHighestSupportedBitrate(true)
+        .setConstrainAudioChannelCountToDeviceCapabilities(false)
         .build();
   }