Use demux-mpegts to demux the video and audio streams so that way it can be able to help media players recover from getting stuck on a black screen/last video frame with the audio playing after discontinuities have stopped being transmitted since it is sending the audio and video separately. Its code is at https://github.com/janbar/demux-mpegts. I want a full, not minimal implementation.

MPC-HC and its derivatives support playing a different audio track by using /dub filename. MKV supports playing a different audio track by using --audio-file=filename. I think VLC also supports that but I didn't find its command line parameter.