Silent microphone audio getUserMedia - web

Question

I've been banging my head against a wall on this for two days now, and I really hope someone can help on this.
I've taken some code for a getUserMedia microphone recorder from https://higuma.github.io/wav-audio-encoder-js/ + https://github.com/higuma/wav-audio-encoder-js here. I've stripped out the components I don't need - and somehow, in the process, I've managed to make it so that there is no audio coming through on the generated file.
It looks like it formats correctly - but is completely silent. I'm getting 0 errors to work from.
// navigator.getUserMedia shim
navigator.getUserMedia = navigator.getUserMedia || navigator.webkitGetUserMedia || navigator.mozGetUserMedia || navigator.msGetUserMedia;
// URL shim
window.URL = window.URL || window.webkitURL;
// audio context + .createScriptProcessor shim
var audioContext = new AudioContext;
if (audioContext.createScriptProcessor == null) {
audioContext.createScriptProcessor = audioContext.createJavaScriptNode;
}
// selectors
var $microphone = $('#microphone');
var $cancel = $('#cancel');
var $recordingList = $('#recording-list');
var $timeDisplay = $('#time-display');
var $microphoneLevel = $('#microphone-level');
var microphone = undefined;
var input = audioContext.createGain();
var mixer = audioContext.createGain();
var microphoneLevel = audioContext.createGain();
microphoneLevel.gain.value = 0;
microphoneLevel.connect(mixer);
var processor = undefined;
var startTime = null;
var encoder = undefined;
// obtaining microphone input
$microphone.click(function() {
navigator.getUserMedia({ audio: true },
function(stream) {
microphone = audioContext.createMediaStreamSource(stream);
microphone.connect(microphoneLevel);
console.log(microphone);
},
function(error) {
window.alert("Could not get audio input");
});
});
// start/stop recording
$microphone.click(function() {
if (startTime != null) {
stopRecording(true);
} else {
startRecording();
}
});
// cancel recording (without saving)
$cancel.click(function() {
stopRecording(false);
});
// microphone level slider
$microphoneLevel.on('input', function() {
var level = $microphoneLevel[0].valueAsNumber / 100;
microphoneLevel.gain.value = level * level;
});
function startRecording() {
startTime = Date.now();
$microphone.html('Stop');
$cancel.removeClass("hidden");
startRecordingProcess();
}
function startRecordingProcess() {
processor = audioContext.createScriptProcessor(1024, 2, 2);
input.connect(processor);
processor.connect(audioContext.destination);
// wav encoder
encoder = new WavAudioEncoder(audioContext.sampleRate, 2);
processor.onaudioprocess = function(event) {
encoder.encode(getBuffers(event));
};
}
function getBuffers(event) {
var buffers = [];
for (var ch = 0; ch < 2; ++ch) {
buffers[ch] = event.inputBuffer.getChannelData(ch);
}
return buffers;
}
function stopRecording(finish) {
startTime = null;
$timeDisplay.html('00:00');
$microphone.html('<i class="start fa fa-microphone fa-5x" aria-hidden="true"></i>');
$cancel.addClass('hidden');
stopRecordingProcess(finish);
}
function stopRecordingProcess(finish) {
input.disconnect();
processor.disconnect();
if (finish) { // if microphone pressed
saveRecording(encoder.finish());
} else { // if cancel pressed
encoder.cancel();
}
}
function saveRecording(blob) {
var url = URL.createObjectURL(blob);
var html = "<p class='recording' recording='" + url + "'><a class='btn btn-default' href='" + url + "' download='recording.wav'>Save Recording</a></p>";
$recordingList.prepend($(html));
// once we have done all the processing, upload the file to beyond verbal
// uploadFile(blob);
}
// update the recording timer
function minuteSeconds(n) { return (n < 10 ? "0" : "") + n; }
function updateDateTime() {
if (startTime !== null) {
var sec = Math.floor((Date.now() - startTime) / 1000);
$timeDisplay.html(minuteSeconds(sec / 60 | 0) + ":" + minuteSeconds(sec % 60));
}
}
window.setInterval(updateDateTime, 200);
If anyone has run into this before, I'd be really appreciative of a fix.
Thank you all for your time, and have a nice day/night

Answer 1

First check your microphone with general recording demo.
If its working you can try passing only Audio Stream & required mime type to media recorder for basic audio recording.
If you want to play with this webaudio context,
Am suspecting issue with microphoneLevel.gain.value = 0;
change it to microphoneLevel.gain.value = 1; //or 2
gain = 0 means we are muting the audio.
gain = 1 default audio level
gain = 0.1 - 0.9 is reducing volume level
gain = above 1.1 increasing the volume level
print the level values in console on
// microphone level slider
$microphoneLevel.on('input', function() {
var level = $microphoneLevel[0].valueAsNumber / 100;
console.log('value: ' + $microphoneLevel[0].valueAsNumber + ' Level: ' + level);
microphoneLevel.gain.value = level * level; // if level is zero, then its silent
// its better if you have a predefined level values based slider position instead of multiplying it
});
See my demo and source