NotReadableError: Failed to allocate audiosource in Firefox for getUserMedia

Question

Running the below snippet in my Firefox console returns the following error [FF/56.0.2 (64-bit) on Mac OS 10.13.1]:

MediaStreamError { name: "NotReadableError", message: "Failed to allocate audiosource", constraint: "", stack: "" } (unknown)

// Sippet
navigator.mediaDevices
      .getUserMedia({
  audio: true,
  video: true
})
      .then(stream=>{
console.log(stream.getAudioTracks())
document.getElementById('storybook-preview-iframe').contentWindow.document.getElementById('video-camera').srcObject = stream
mr = new window.MediaRecorder(stream,  {
      mimeType: 'video/webm'
    })
mr.ondataavailable = console.log
})
      .catch(console.log)

What is most troubling is it worked at one point, and then it stopped. As if something is permanently locked up... I have no way (as far as I can tell) to see what is wrong with the audio source.

I ran these insanity checks to no avail:

• No other browsers or app were open and/or using camera
• Restarted browser, and eventually restarted computer
• I'm on a mac, and heard this would help #> sudo killall AppleCameraAssistant;sudo killall VDCAssistant. It did not.
• Ran a separate script (https://jsfiddle.net/App7P/348/) but when I turned the audio to true (https://jsfiddle.net/3k89sy27/2/), I got the same error as above.
• This example/demo page on getusermedia also garnered the same error: https://webrtc.github.io/samples/src/content/getusermedia/record/

Update: I've simplified the failure code even more.

navigator.mediaDevices.getUserMedia({
    audio: true
}).then(function (stream) {
    console.log(stream)
}).catch(console.log)

Audio does not want to register.....

Even tried FF's own Test Pilot and that failed too https://testpilot.firefox.com/experiments/voice-fill/

Answer 1

as @mrchestnut suggested, I downloaded Firefox Quantum (which was released as of Nov. 14th 2017) and it worked!

Blog Post on Mozilla:

https://blog.mozilla.org/blog/2017/11/14/introducing-firefox-quantum/

Download Quantum:

https://www.mozilla.org/en-US/firefox/new/?scene=2

Although this doesn't explain why it didn't work, it sure has sugar solved my problem.