When load a video (VideoCastManager.loadMedia()) I store custom data on MediaInfo (MediaInfo.Builder.setCustomData). Is there a way to change that custom data without re-loading the video?
Not really. However, other control methods (such as play, pause, ..) also accept custom data. Can you use those to accomplish what you need to do? If not, the cleanest solution is to create a custom namespace for sending messages/data; it is almost trivial to set that up.