Merge pull request #1304 from nfb-onf/disable_airplay_for_sideloaded_captions

disable airplay when sideloaded captions

README.md

@@ -656,6 +656,8 @@ uri | URL for the text track. Currently, only tracks hosted on a webserver are s
 
 On iOS, sidecar text tracks are only supported for individual files, not HLS playlists. For HLS, you should include the text tracks as part of the playlist.
 
+Note: Due to iOS limitations, sidecar text tracks are not compatible with Airplay. If textTracks are specified, AirPlay support will be automatically disabled.
+
 Example:
 ```
 import { TextTrackType }, Video from 'react-native-video';

ios/Video/RCTVideo.m

@@ -401,10 +401,13 @@ static int const RCTVideoUnset = -1;
 
 - (void)playerItemPrepareText:(AVAsset *)asset assetOptions:(NSDictionary * __nullable)assetOptions withCallback:(void(^)(AVPlayerItem *))handler
 {
-  if (!_textTracks) {
+  if (!_textTracks || _textTracks.count==0) {
     handler([AVPlayerItem playerItemWithAsset:asset]);
     return;
   }
+  
+  // AVPlayer can't airplay AVMutableCompositions
+  _allowsExternalPlayback = NO;
 
   // sideload text tracks
   AVMutableComposition *mixComposition = [[AVMutableComposition alloc] init];