WebRTC video/audio streams out of sync (MediaStream -> MediaRecorder -> MediaSource -> Video Element)

A late reply to an old post, but it might help someone ...

I had exactly the same problem: I have a video stream, which should be supplemented by an audio stream. In the audio stream short sounds (AudioBuffer) are played from time to time. The whole thing is recorded via MediaRecorder. Everything works fine on Chrome. But on Chrome for Android, all sounds were played back in quick succession. The "when" parameter for "play()" was ignored on Android. (audiocontext.currentTime continued to increase over time ... - that was not the point).

My solution is similar to Jacob's comment Sep 2 '18 at 7:41: I created and connected a sine wave oscillator with inaudible 48,000 Hz, which played permanently in the audio stream during recording. Apparently this leads to the proper time progress.