mozChannels/mozSampleRate is undefined

I am using the this within an audio experiment of mine.

audiometa: function(){
        channels = audio.mozChannels;
        rate = audio.mozSampleRate;
        frameBufferLength = audio.mozFrameBufferLength;

        fft = new FFT(frameBufferLength / channels, rate);
    },

For some reason, mozChannels/mozSampleRate and mozFrameBufferLength is undefined using the latest version of Firefox. Reading the cos, I can't explain myself, why this could happen.

Is there something within the about:config page which I need to turn on? (Have tried it local and on a webserver)

By the way, I am using this example. http://ift.tt/1L2WFoG

Thanks