README: extend the CORS headers note for media files for Google Cast

Author: Eugene Nikolskyi

README.md

@@ -86,7 +86,7 @@ All of the test targets are compiled when the main `ConnectSDK` scheme is built,
 
 - DLNA service supports `SRT` format only. Since there is no official specification for them, subtitles may not work on all DLNA-compatible devices. This feature has been tested and works on LG WebOS and Netcast TVs.
 - Netcast service supports `SRT` format only, through DLNA.
-- Google Cast service supports `WebVTT` format only. The server providing subtitles should support CORS headers, otherwise they are not displayed. The simplest change is to send this HTTP response header for your subtitles: `Access-Control-Allow-Origin: *`. More information is here: [https://developers.google.com/cast/docs/ios_sender#cors-requirements](https://developers.google.com/cast/docs/ios_sender#cors-requirements).
+- Google Cast service supports `WebVTT` format only. Servers providing subtitles and media files should support [CORS](https://en.wikipedia.org/wiki/Cross-origin_resource_sharing) headers (unless they are of the same origin). The simplest change is to send this HTTP response header for your files: `Access-Control-Allow-Origin: *`. More information is here: [https://developers.google.com/cast/docs/ios_sender#cors-requirements](https://developers.google.com/cast/docs/ios_sender#cors-requirements).
 - FireTV service supports `WebVTT` format only. Subtitles on Fire TV are hidden by default. To display them, the user should manually pick one in the media player (click the "Options" button on the remote). The Fling SDK doesn't provide any way to make them appear remotely.
 - WebOS service supports `WebVTT` format only. Server providing subtitles should support CORS headers, similarly to Cast service's requirements.