added an onCaptionsDeviceSettings event

Video.js

@@ -151,6 +151,12 @@ export default class Video extends Component {
     }
   };
 
+  _onCaptionsDeviceSetting = (event) => {
+    if (this.props.onCaptionsDeviceSetting) {
+      this.props.onCaptionsDeviceSetting(event.nativeEvent);
+    }
+  };
+
   _onPlaybackStalled = (event) => {
     if (this.props.onPlaybackStalled) {
       this.props.onPlaybackStalled(event.nativeEvent);
@@ -241,6 +247,7 @@ export default class Video extends Component {
       onVideoFullscreenPlayerWillDismiss: this._onFullscreenPlayerWillDismiss,
       onVideoFullscreenPlayerDidDismiss: this._onFullscreenPlayerDidDismiss,
       onReadyForDisplay: this._onReadyForDisplay,
+      onCaptionsDeviceSetting: this._onCaptionsDeviceSetting,
       onPlaybackStalled: this._onPlaybackStalled,
       onPlaybackResume: this._onPlaybackResume,
       onPlaybackRateChange: this._onPlaybackRateChange,
@@ -379,6 +386,7 @@ Video.propTypes = {
   onFullscreenPlayerWillDismiss: PropTypes.func,
   onFullscreenPlayerDidDismiss: PropTypes.func,
   onReadyForDisplay: PropTypes.func,
+  onCaptionsDeviceSetting: PropTypes.func,
   onPlaybackStalled: PropTypes.func,
   onPlaybackResume: PropTypes.func,
   onPlaybackRateChange: PropTypes.func,

ios/RCTVideo.h

@@ -23,6 +23,7 @@
 @property (nonatomic, copy) RCTBubblingEventBlock onVideoFullscreenPlayerWillDismiss;
 @property (nonatomic, copy) RCTBubblingEventBlock onVideoFullscreenPlayerDidDismiss;
 @property (nonatomic, copy) RCTBubblingEventBlock onReadyForDisplay;
+@property (nonatomic, copy) RCTBubblingEventBlock onCaptionsDeviceSetting;
 @property (nonatomic, copy) RCTBubblingEventBlock onPlaybackStalled;
 @property (nonatomic, copy) RCTBubblingEventBlock onPlaybackResume;
 @property (nonatomic, copy) RCTBubblingEventBlock onPlaybackRateChange;

ios/RCTVideo.m

@@ -59,6 +59,7 @@ static int const RCTVideoUnset = -1;
   NSDictionary* _fullscreenOptions;
   BOOL _fullscreenPlayerPresented;
   UIViewController * _presentingViewController;
+  BOOL _deviceCaptionsEnabled;
 }
 
 - (instancetype)initWithEventDispatcher:(RCTEventDispatcher *)eventDispatcher
@@ -316,6 +317,10 @@ static int const RCTVideoUnset = -1;
   [self removePlayerTimeObserver];
   [self removePlayerItemObservers];
   
+  CFArrayRef captioningMediaCharacteristics = MACaptionAppearanceCopyPreferredCaptioningMediaCharacteristics(kMACaptionAppearanceDomainUser);
+  NSArray *captionSettings = (__bridge NSArray*)captioningMediaCharacteristics;
+  _deviceCaptionsEnabled = [captionSettings containsObject:AVMediaCharacteristicTranscribesSpokenDialogForAccessibility];
+  
   dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
     
     // perform on next run loop, otherwise other passed react-props may not be set
@@ -353,6 +358,12 @@ static int const RCTVideoUnset = -1;
                               });
     }
     
+    if (self.onCaptionsDeviceSetting) {
+      self.onCaptionsDeviceSetting(@{@"deviceCaptionsEnabled": [NSNumber numberWithBool:_deviceCaptionsEnabled],
+                                     @"target": self.reactTag
+                                     });
+    }
+    
   });
   _videoLoadStarted = YES;
 }
@@ -875,9 +886,7 @@ static int const RCTVideoUnset = -1;
   
   // in the situation that a selected text track is not available (eg. specifies a textTrack not available)
   if (![type isEqualToString:@"disabled"] && selectedTrackIndex == RCTVideoUnset) {
-    CFArrayRef captioningMediaCharacteristics = MACaptionAppearanceCopyPreferredCaptioningMediaCharacteristics(kMACaptionAppearanceDomainUser);
-    NSArray *captionSettings = (__bridge NSArray*)captioningMediaCharacteristics;
-    if ([captionSettings containsObject:AVMediaCharacteristicTranscribesSpokenDialogForAccessibility]) {
+    if (_deviceCaptionsEnabled) {
       selectedTrackIndex = 0; // If we can't find a match, use the first available track
       NSString *systemLanguage = [[NSLocale preferredLanguages] firstObject];
       for (int i = 0; i < textTracks.count; ++i) {

ios/RCTVideoManager.m

@@ -54,6 +54,7 @@ RCT_EXPORT_VIEW_PROPERTY(onVideoFullscreenPlayerDidPresent, RCTBubblingEventBloc
 RCT_EXPORT_VIEW_PROPERTY(onVideoFullscreenPlayerWillDismiss, RCTBubblingEventBlock);
 RCT_EXPORT_VIEW_PROPERTY(onVideoFullscreenPlayerDidDismiss, RCTBubblingEventBlock);
 RCT_EXPORT_VIEW_PROPERTY(onReadyForDisplay, RCTBubblingEventBlock);
+RCT_EXPORT_VIEW_PROPERTY(onCaptionsDeviceSetting, RCTBubblingEventBlock);
 RCT_EXPORT_VIEW_PROPERTY(onPlaybackStalled, RCTBubblingEventBlock);
 RCT_EXPORT_VIEW_PROPERTY(onPlaybackResume, RCTBubblingEventBlock);
 RCT_EXPORT_VIEW_PROPERTY(onPlaybackRateChange, RCTBubblingEventBlock);