@speechly/browser-client/core/microphone/audioworklet.d.ts

JavaScript client for Speechly Streaming API

declare const _default: "\n// Indices for the Control SAB.\nconst CONTROL = {\n  'WRITE_INDEX': 0,\n  'FRAMES_AVAILABLE': 1,\n  'LOCK': 2,\n};\n\nclass SpeechlyProcessor extends AudioWorkletProcessor {\n  constructor() {\n    super();\n\n    this._initialized = false;\n    this.debug = false;\n    this.port.onmessage = this._initialize.bind(this);\n  }\n\n  _initialize(event) {\n    this.controlSAB = new Int32Array(event.data.controlSAB);\n    this.dataSAB = new Float32Array(event.data.dataSAB);\n    this.debug = event.data.debug;\n    if (this.debug) {\n      console.log('[BrowserClient AudioWorkletNode]', 'initializing audioworklet');\n    }\n    this.sharedBufferSize = this.dataSAB.length;\n    this.buffer = new Float32Array(0);\n    this._initialized = true;\n  }\n\n  _transferDataToSharedBuffer(data) {\n    this.controlSAB[CONTROL.LOCK] = 1;\n    let inputWriteIndex = this.controlSAB[CONTROL.WRITE_INDEX];\n    if (this.controlSAB[CONTROL.FRAMES_AVAILABLE] > 0) {\n      if (inputWriteIndex + data.length > this.sharedBufferSize) {\n        // console.log('buffer overflow')\n        inputWriteIndex = 0;\n      }\n    }\n    this.dataSAB.set(data, inputWriteIndex);\n    this.controlSAB[CONTROL.WRITE_INDEX] = inputWriteIndex + data.length;\n    this.controlSAB[CONTROL.FRAMES_AVAILABLE] = inputWriteIndex + data.length;\n    this.controlSAB[CONTROL.LOCK] = 0;\n  }\n\n  _pushData(data) {\n    if (this.debug) {\n      const signalEnergy = getStandardDeviation(data)\n      this.port.postMessage({\n        type: 'STATS',\n        signalEnergy: signalEnergy,\n        samples: data.length,\n      });\n    }\n\n    if (this.buffer.length > this.sharedBufferSize) {\n      const dataToTransfer = this.buffer.subarray(0, this.sharedBufferSize);\n      this._transferDataToSharedBuffer(dataToTransfer);\n      this.buffer = this.buffer.subarray(this.sharedBufferSize);\n    }\n    let concat = new Float32Array(this.buffer.length + data.length);\n    concat.set(this.buffer);\n    concat.set(data, this.buffer.length);\n    this.buffer = concat;\n  }\n\n  process(inputs, outputs, parameters) {\n    const inputChannelData = inputs[0][0];\n    if (inputChannelData !== undefined) {\n      if (this.controlSAB && this.dataSAB) {\n        this._pushData(inputChannelData);\n      } else {\n        this.port.postMessage({\n          type: 'DATA',\n          frames: inputChannelData\n        });\n      }\n    }\n\n    return true;\n  }\n}\n\nfunction getStandardDeviation(array) {\n  const n = array.length\n  const mean = array.reduce((a, b) => a + b) / n\n  return Math.sqrt(array.map(x => Math.pow(x - mean, 2)).reduce((a, b) => a + b) / n)\n}\n\nregisterProcessor('speechly-worklet', SpeechlyProcessor);\n";
export default _default;