Add existing code

src/lib/recorder.js

@@ -0,0 +1,110 @@
+import WavEncoder from './wav-encoder'
+import { convertTimeMMSS } from './utils'
+
+export default class {
+  constructor (options = {}) {
+    this.afterStop = options.afterStop
+    this.micFailed = options.micFailed
+
+    this.bufferSize = 4096
+    this.records    = []
+    this.samples    = []
+
+    this.isPause      = false
+    this.isRecording  = false
+
+    this.duration = 0
+    this.volume   = 0
+
+    this._duration = 0
+  }
+
+  start () {
+    navigator.mediaDevices.getUserMedia({audio: true})
+                          .then(this._micCaptured.bind(this))
+                          .catch(this._micError.bind(this))
+    this.isPause = false
+    this.isRecording = true
+  }
+
+  stop () {
+    this.stream.getTracks().forEach((track) => track.stop())
+    this.input.disconnect()
+    this.processor.disconnect()
+    this.context.close()
+
+    let encoder = new WavEncoder({
+      bufferSize: this.bufferSize,
+      sampleRate: this.context.sampleRate,
+      samples: this.samples
+    })
+
+    let audioBlob = encoder.getData()
+    let audioUrl = URL.createObjectURL(audioBlob)
+
+    this.samples = []
+
+    this.records.push({
+      blob: audioBlob,
+      url: audioUrl,
+      duration: convertTimeMMSS(this.duration)
+    })
+
+    this.isPause = false
+    this.isRecording = false
+    this._duration = 0
+    this.duration = 0
+
+    if (this.afterStop) {
+      this.afterStop()
+    }
+  }
+
+  pause () {
+    this.stream.getTracks().forEach((track) => track.stop())
+    this.input.disconnect()
+    this.processor.disconnect()
+    this.context.close()
+
+    this._duration = this.duration
+    this.isPause = true
+  }
+
+  recordList () {
+    return this.records
+  }
+
+  lastRecord () {
+    return this.records.slice(-1)
+  }
+
+  _micCaptured (stream) {
+    this.context = new AudioContext()
+    this.input = this.context.createMediaStreamSource(stream)
+    this.processor = this.context.createScriptProcessor(this.bufferSize, 1, 1)
+    this.duration = this._duration
+    this.stream = stream
+
+    this.processor.onaudioprocess = (ev) => {
+      let sample = ev.inputBuffer.getChannelData(0)
+      let sum    = 0.0
+
+      for (let i = 0; i < sample.length; ++i) {
+        sum += sample[i] * sample[i]
+      }
+
+      this.duration = parseFloat(this._duration) + parseFloat(this.context.currentTime.toFixed(2))
+      this.volume = Math.sqrt(sum / sample.length).toFixed(2)
+      this.samples.push(new Float32Array(sample))
+    }
+
+    this.input.connect(this.processor)
+    this.processor.connect(this.context.destination)
+  }
+
+  _micError (error) {
+    if (this.micFailed) {
+      this.micFailed(error)
+    }
+  }
+}

src/lib/utils.js

@@ -0,0 +1,22 @@
+export function calculateLineHeadPosition (ev, element) {
+  let progressWidth = element.getBoundingClientRect().width
+  let leftPosition = ev.target.getBoundingClientRect().left
+  let pos = (ev.clientX - leftPosition) / progressWidth
+
+  try {
+    if (!ev.target.className.match(/^ar\-line\-control/)) {
+      return
+    }
+  } catch (err) {
+    return
+  }
+
+  pos = pos < 0 ? 0 : pos
+  pos = pos > 1 ? 1 : pos
+
+  return pos
+}
+
+export function convertTimeMMSS (seconds) {
+  return new Date(seconds * 1000).toISOString().substr(14, 5)
+}

src/lib/wav-encoder.js

@@ -0,0 +1,59 @@
+export default class {
+  constructor (options) {
+    this.bufferSize = options.bufferSize || 4096
+    this.sampleRate = options.sampleRate
+    this.samples    = options.samples
+  }
+
+  getData () {
+    this._joinSamples()
+
+    let buffer = new ArrayBuffer(44 + this.samples.length * 2)
+    let view   = new DataView(buffer)
+
+    this._writeString(view, 0, 'RIFF')                       // RIFF identifier
+    view.setUint32(4, 36 + this.samples.length * 2, true)    // RIFF chunk length
+    this._writeString(view, 8, 'WAVE')                       // RIFF type
+    this._writeString(view, 12, 'fmt ')                      // format chunk identifier
+    view.setUint32(16, 16, true)                             // format chunk length
+    view.setUint16(20, 1, true)                              // sample format (raw)
+    view.setUint16(22, 1, true)                              // channel count
+    view.setUint32(24, this.sampleRate, true)                // sample rate
+    view.setUint32(28, this.sampleRate * 4, true)            // byte rate (sample rate * block align)
+    view.setUint16(32, 4, true)                              // block align (channel count * bytes per sample)
+    view.setUint16(34, 16, true)                             // bits per sample
+    this._writeString(view, 36, 'data')                      // data chunk identifier
+    view.setUint32(40, this.samples.length * 2, true)        // data chunk length
+
+    this._floatTo16BitPCM(view, 44, this.samples)
+
+    return new Blob([view], {type: 'audio/wav'})
+  }
+
+  _floatTo16BitPCM (output, offset, input) {
+    for (let i = 0; i < input.length; i++, offset += 2) {
+      let s = Math.max(-1, Math.min(1, input[i]))
+      output.setInt16(offset, s < 0 ? s * 0x8000 : s * 0x7FFF, true)
+    }
+  }
+
+  _joinSamples () {
+    let recordLength  = this.samples.length * this.bufferSize
+    let joinedSamples = new Float64Array(recordLength)
+    let offset        = 0
+
+    for (let i = 0; i < this.samples.length; i++) {
+      let sample = this.samples[i]
+      joinedSamples.set(sample, offset)
+      offset += sample.length
+    }
+
+    this.samples = joinedSamples
+  }
+
+  _writeString (view, offset, string) {
+    for (let i = 0; i < string.length; i++) {
+      view.setUint8(offset + i, string.charCodeAt(i))
+    }
+  }
+}