I was wondering the same thing just a few days ago.
It is actually quite trivial to add an audio-stream (or streams) with the director/writer/actors commentary to HLS or MPEG-DASH and surface it in the application UIs.
I saw a very nice use of this in the IPL (India Premier League) cricket match yesterday. JioCinema is the streamer offering the match streams and they have an option to change the camera view. Of the multiple cameras in the stadium, you could pick a camera angle that you wanted. It was pretty cool.
It is actually quite trivial to add an audio-stream (or streams) with the director/writer/actors commentary to HLS or MPEG-DASH and surface it in the application UIs.
I saw a very nice use of this in the IPL (India Premier League) cricket match yesterday. JioCinema is the streamer offering the match streams and they have an option to change the camera view. Of the multiple cameras in the stadium, you could pick a camera angle that you wanted. It was pretty cool.