I am using lib-jitsi-meet js, I take the file and I mix it with the local track.
I have the audiomixer but is not clear to me how I can remove the microphone audio track and put the mixed one
var objectURL = window.URL.createObjectURL(document.getElementById("audio-mp3").files[0]);
var audio = new Audio(objectURL);
var stream = audio.captureStream();
var audio_mixer = JitsiMeetJS.createAudioMixer();
audio_mixer.addMediaStream(localTracks[0].getOriginalStream())
audio_mixer.addMediaStream(stream)
return audio_mixer