_initMicVolumeProcessor()

in lex-web-ui/src/lib/lex/recorder.js [458:504]

• 42 lines of code
• 7 McCabe index (conditional complexity)

  _initMicVolumeProcessor() {
    /* eslint no-plusplus: ["error", { "allowForLoopAfterthoughts": true }] */
    // assumes a single channel - XXX does it need to handle 2 channels?
    const processor = this._audioContext.createScriptProcessor(
      this.bufferLength,
      this.numChannels,
      this.numChannels,
    );
    processor.onaudioprocess = (evt) => {
      if (this._state === 'recording') {
        // send buffers to worker
        this._recordBuffers(evt.inputBuffer);

        // stop recording if over the maximum time
        if ((this._audioContext.currentTime - this._recordingStartTime)
          > this.recordingTimeMax
        ) {
          console.warn('stopped recording due to maximum time');
          this.stop();
        }
      }

      // XXX assumes mono channel
      const input = evt.inputBuffer.getChannelData(0);
      let sum = 0.0;
      let clipCount = 0;
      for (let i = 0; i < input.length; ++i) {
        // square to calculate signal power
        sum += input[i] * input[i];
        if (Math.abs(input[i]) > 0.99) {
          clipCount += 1;
        }
      }
      this._instant = Math.sqrt(sum / input.length);
      this._slow = (0.95 * this._slow) + (0.05 * this._instant);
      this._clip = (input.length) ? clipCount / input.length : 0;

      this._setIsMicMuted();
      this._setIsMicQuiet();

      this._analyser.getFloatFrequencyData(this._analyserData);
      this._maxVolume = Math.max(...this._analyserData);
    };

    this._micVolumeProcessor = processor;
    return Promise.resolve();
  }