export default class Recorder {
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constructor(stream, config) {
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//兼容
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window.URL = window.URL || window.webkitURL
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navigator.getUserMedia =
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navigator.getUserMedia ||
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navigator.webkitGetUserMedia ||
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navigator.mozGetUserMedia ||
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navigator.msGetUserMedia
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config = config || {}
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config.sampleBits = config.sampleBits || 16 //采样数位 8, 16
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config.sampleRate = config.sampleRate || 8000 //采样率(1/6 44100)
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this.context = new (window.webkitAudioContext || window.AudioContext)()
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this.audioInput = this.context.createMediaStreamSource(stream)
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this.createScript =
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this.context.createScriptProcessor || this.context.createJavaScriptNode
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this.recorder = this.createScript.apply(this.context, [4096, 1, 1])
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this.audioData = {
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size: 0, //录音文件长度
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buffer: [], //录音缓存
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inputSampleRate: this.context.sampleRate, //输入采样率
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inputSampleBits: 16, //输入采样数位 8, 16
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outputSampleRate: config.sampleRate, //输出采样率
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oututSampleBits: config.sampleBits, //输出采样数位 8, 16
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input: function(data) {
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this.buffer.push(new Float32Array(data))
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this.size += data.length
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},
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compress: function() {
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//合并压缩
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//合并
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let data = new Float32Array(this.size)
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let offset = 0
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for (let i = 0; i < this.buffer.length; i++) {
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data.set(this.buffer[i], offset)
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offset += this.buffer[i].length
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}
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//压缩
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let compression = parseInt(this.inputSampleRate / this.outputSampleRate)
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let length = data.length / compression
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let result = new Float32Array(length)
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let index = 0,
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j = 0
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while (index < length) {
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result[index] = data[j]
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j += compression
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index++
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}
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return result
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},
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encodeWAV: function() {
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let sampleRate = Math.min(this.inputSampleRate, this.outputSampleRate)
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let sampleBits = Math.min(this.inputSampleBits, this.oututSampleBits)
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let bytes = this.compress()
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let dataLength = bytes.length * (sampleBits / 8)
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let buffer = new ArrayBuffer(44 + dataLength)
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let data = new DataView(buffer)
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let channelCount = 1 //单声道
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let offset = 0
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let writeString = function(str) {
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for (let i = 0; i < str.length; i++) {
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data.setUint8(offset + i, str.charCodeAt(i))
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}
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}
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// 资源交换文件标识符
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writeString('RIFF')
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offset += 4
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// 下个地址开始到文件尾总字节数,即文件大小-8
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data.setUint32(offset, 36 + dataLength, true)
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offset += 4
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// WAV文件标志
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writeString('WAVE')
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offset += 4
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// 波形格式标志
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writeString('fmt ')
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offset += 4
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// 过滤字节,一般为 0x10 = 16
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data.setUint32(offset, 16, true)
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offset += 4
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// 格式类别 (PCM形式采样数据)
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data.setUint16(offset, 1, true)
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offset += 2
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// 通道数
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data.setUint16(offset, channelCount, true)
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offset += 2
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// 采样率,每秒样本数,表示每个通道的播放速度
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data.setUint32(offset, sampleRate, true)
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offset += 4
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// 波形数据传输率 (每秒平均字节数) 单声道×每秒数据位数×每样本数据位/8
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data.setUint32(
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offset,
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channelCount * sampleRate * (sampleBits / 8),
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true
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)
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offset += 4
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// 快数据调整数 采样一次占用字节数 单声道×每样本的数据位数/8
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data.setUint16(offset, channelCount * (sampleBits / 8), true)
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offset += 2
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// 每样本数据位数
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data.setUint16(offset, sampleBits, true)
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offset += 2
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// 数据标识符
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writeString('data')
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offset += 4
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// 采样数据总数,即数据总大小-44
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data.setUint32(offset, dataLength, true)
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offset += 4
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// 写入采样数据
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if (sampleBits === 8) {
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for (let i = 0; i < bytes.length; i++, offset++) {
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let s = Math.max(-1, Math.min(1, bytes[i]))
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let val = s < 0 ? s * 0x8000 : s * 0x7fff
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val = parseInt(255 / (65535 / (val + 32768)))
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data.setInt8(offset, val, true)
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}
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} else {
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for (let i = 0; i < bytes.length; i++, offset += 2) {
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let s = Math.max(-1, Math.min(1, bytes[i]))
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data.setInt16(offset, s < 0 ? s * 0x8000 : s * 0x7fff, true)
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}
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}
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return new Blob([data], {
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type: 'audio/wav',
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})
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},
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}
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}
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//开始录音
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start() {
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this.audioInput.connect(this.recorder)
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this.recorder.connect(this.context.destination)
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//音频采集
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let self = this
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this.recorder.onaudioprocess = function(e) {
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self.audioData.input(e.inputBuffer.getChannelData(0))
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}
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}
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//停止
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stop() {
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this.recorder.disconnect()
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}
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//获取音频文件
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getBlob() {
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this.stop()
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return this.audioData.encodeWAV()
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}
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//回放
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play(audio) {
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audio.src = window.URL.createObjectURL(this.getBlob())
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}
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//清理缓存的录音数据
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clear(audio) {
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this.audioData.buffer = []
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this.audioData.size = 0
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audio.src = ''
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}
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static checkError(e) {
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const { name } = e
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let errorMsg = ''
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switch (name) {
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case 'AbortError':
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errorMsg = '录音设备无法被使用'
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break
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case 'NotAllowedError':
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errorMsg = '用户已禁止网页调用录音设备'
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break
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case 'PermissionDeniedError':
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errorMsg = '用户已禁止网页调用录音设备'
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break // 用户拒绝
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case 'NotFoundError':
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errorMsg = '录音设备未找到'
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break
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case 'DevicesNotFoundError':
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errorMsg = '录音设备未找到'
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break
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case 'NotReadableError':
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errorMsg = '录音设备无法使用'
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break
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case 'NotSupportedError':
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errorMsg = '不支持录音功能'
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break
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case 'MandatoryUnsatisfiedError':
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errorMsg = '无法发现指定的硬件设备'
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break
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default:
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errorMsg = '录音调用错误'
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break
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}
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return {
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error: errorMsg,
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}
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}
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static get(callback, config) {
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if (callback) {
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if (navigator.mediaDevices && navigator.mediaDevices.getUserMedia) {
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navigator.mediaDevices
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.getUserMedia({
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audio: true,
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video: false,
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})
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.then(stream => {
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let rec = new Recorder(stream, config)
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callback(rec)
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})
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.catch(e => {
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callback(Recorder.checkError(e))
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})
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} else {
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navigator
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.getUserMedia({
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audio: true,
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video: false,
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})
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.then(stream => {
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let rec = new Recorder(stream, config)
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callback(rec)
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})
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.catch(e => {
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// Recorder.checkError(e)
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callback(Recorder.checkError(e))
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})
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}
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}
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}
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}
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