I'm trying to implement a YouTube Live Streaming Overlay: the live stream is a sport event and I need to put an overlay with the realtime score of the event.
Here's the questions:
Is it possibile to add a "native" overlay i.e. mix 2 streams (the video and a fake stream with the score) to produce a single broadcast event?
Is it possibile to add the overlay client-side with JavaScript? How can I synchronize the livestream (which can be lagged) with the score that is received by JavaScript in realtime?
Is it possibile to add subtitles in realtime to mimic an overlay with the score?
Yes, you can definitely overlay the stream, add more metadata etc. But you can not do those with API. You can do the overlay on your own client and stream to YT the final version.