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/**
* Copyright 2024 Google LLC
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
const VolMeterWorket = `
class VolMeter extends AudioWorkletProcessor {
volume
updateIntervalInMS
nextUpdateFrame
constructor() {
super()
this.volume = 0
this.updateIntervalInMS = 25
this.nextUpdateFrame = this.updateIntervalInMS
this.port.onmessage = event => {
if (event.data.updateIntervalInMS) {
this.updateIntervalInMS = event.data.updateIntervalInMS
}
}
}
get intervalInFrames() {
return (this.updateIntervalInMS / 1000) * sampleRate
}
process(inputs) {
const input = inputs[0]
if (input.length > 0) {
const samples = input[0]
let sum = 0
let rms = 0
for (let i = 0; i < samples.length; ++i) {
sum += samples[i] * samples[i]
}
rms = Math.sqrt(sum / samples.length)
this.volume = Math.max(rms, this.volume * 0.7)
this.nextUpdateFrame -= samples.length
if (this.nextUpdateFrame < 0) {
this.nextUpdateFrame += this.intervalInFrames
this.port.postMessage({volume: this.volume})
}
}
return true
}
}`;
export default VolMeterWorket;