MediaRecorder: how to get sample rate and sample size

[Morgane Daniel]

Hi,

I have a question regarding the MediaRecorder API, I hope this list is the
good place to ask this!
I try to record an audio track from the microphone and so far I succeed in
getting an array of bytes in a Blob. My problem is I could not get the
sample rate and the sample size. The method getSettings() seems to be the
perfect candidate but it is not supported on Chrome neither on Firefox. I
also tried the applyConstraints() method to fix a sample rate and a sample
size but it seems not being applied (I had no more bytes if I tried to
increase the sample rate for example), however I can read those constraints
in getConstraints.
Could you tell me what I am doing wrong please? I don't get it!
thank you !

let AudioFormat = {
sampleSize: 16,
channelCount: 1,
sampleRate: 16000
}

navigator.mediaDevices.getUserMedia({ audio: AudioFormat, video:
false })
.then( function(stream) {
const media_recorder = new MediaRecorder(stream);

media_recorder.start( recording_length );
media_recorder.onstart = function(){
console.log("Starting recording")
}

media_recorder.ondataavailable = function( event ){
var reader = new FileReader();
reader.addEventListener("loadend", function() {
console.log( new Uint8Array( reader.result ) )
});

}