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Re-implement loudness block

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Eric Rosenbaum 2017-06-20 18:34:12 -04:00
parent 03034dd2f7
commit 2974a5e65b
1 changed files with 37 additions and 10 deletions
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47
src/index.js
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@ -289,20 +289,47 @@ class AudioEngine {
/**
* Get the current loudness of sound received by the microphone.
* Sound is measured in RMS and smoothed.
* Some code adapted from Tone.js: https://github.com/Tonejs/Tone.js
* @return {number} loudness scaled 0 to 100
*/
getLoudness () {
// if (!this.mic) {
// this.mic = new Tone.UserMedia();
// this.micMeter = new Tone.Meter('level', 0.5);
// this.mic.open();
// this.mic.connect(this.micMeter);
// }
// if (this.mic && this.mic.state === 'started') {
// return this.micMeter.value * 100;
// }
return -1;
// the microphone has not been set up, try to connect to it
if (!this.mic && !this.connectingToMic) {
this.connectingToMic = true; // prevent multiple connection attempts
navigator.mediaDevices.getUserMedia({audio : true}).then(stream => {
this.mic = this.context.createMediaStreamSource(stream);
this.analyser = this.context.createAnalyser();
this.mic.connect(this.analyser);
this.micDataArray = new Float32Array(this.analyser.fftSize);
}).catch(err => {
log.warn(err)
});
}
// if the microphone is set up and active, measure the loudness
if (this.mic && this.mic.mediaStream.active) {
this.analyser.getFloatTimeDomainData(this.micDataArray);
let sum = 0;
// compute the RMS of the sound
for (let i = 0; i < this.micDataArray.length; i++){
sum += Math.pow(this.micDataArray[i], 2);
}
let rms = Math.sqrt(sum / this.micDataArray.length);
// smooth the value, if it is descending
if (this._lastValue) {
rms = Math.max(rms, this._lastValue * 0.5);
}
this._lastValue = rms;
// scale it
// @todo figure out why this magic number is needed and remove it!
rms *= 1.63;
// scale and round the output
return Math.round(Math.sqrt(rms) * 100);
}
// if there is no microphone input, return -1
return -1;
}
/**