ArrayBuffer内存格式相互转换 ArrayBuffer转化16进制 16进制转字符串 pcm转wav音频

一： pcm转wav音频
针对于音频格式的转换

const encodeWAV = (samples, numChannels, sampleRate) => {
  var buffer = new ArrayBuffer(44 + samples.byteLength)
  var view = new DataView(buffer)
  /* RIFF identifier */
  writeString(view, 0, 'RIFF')
  /* RIFF chunk length */
  view.setUint32(4, 36 + samples.byteLength, true)
  /* RIFF type */
  writeString(view, 8, 'WAVE')
  /* format chunk identifier */
  writeString(view, 12, 'fmt ')
  /* format chunk length */
  view.setUint32(16, 16, true)
  /* sample format (raw) */
  view.setUint16(20, 1, true)
  /* channel count */
  view.setUint16(22, numChannels, true)
  /* sample rate */
  view.setUint32(24, sampleRate, true)
  /* byte rate (sample rate * block align) */
  view.setUint32(28, sampleRate * 4, true)
  /* block align (channel count * bytes per sample) */
  view.setUint16(32, numChannels * 2, true)
  /* bits per sample */
  view.setUint16(34, 16, true)
  /* data chunk identifier */
  writeString(view, 36, 'data')
  /* data chunk length */
  view.setUint32(40, samples.byteLength, true)

  copyBytes(view, 44, samples)

  return view
}
const copyBytes = (output, offset, input) => {
  const dataView = new DataView(input)
  for (var i = 0; i < input.byteLength; i++, offset++) {
    output.setInt8(offset, dataView.getInt8(i))
  }
}
const writeString = (view, offset, string) => {
  for (var i = 0; i < string.length; i++) {
    view.setUint8(offset + i, string.charCodeAt(i))
  }
}

二： ArrayBuffer转16进制

const buf2hex = (arrayBuffer) => {
 let hex = ''
  let uint8Array = new Uint8Array(arrayBuffer)
  for (let i = 0; i < uint8Array.length; i++) {
    // 将字节转换为16进制字符串，并添加到hex中
    hex += uint8Array[i].toString(16).padStart(2, '0') // 使用padStart确保总是两位数
  }
  return hex
}

三：16进制转字符串

const hexToString = (str: any) => {
 var val = '',
    len = str.length / 2
  for (var i = 0; i < len; i++) {
    val += String.fromCharCode(parseInt(str.substr(i * 2, 2), 16))
  }
  return utf8to16(val)
}
//处理中文乱码问题
const utf8to16 = (str) => {
  var out, i, len, c
  var char2, char3
  out = ''
  len = str.length
  i = 0
  while (i < len) {
    c = str.charCodeAt(i++)
    switch (c >> 4) {
      case 0:
      case 1:
      case 2:
      case 3:
      case 4:
      case 5:
      case 6:
      case 7:
        out += str.charAt(i - 1)
        break
      case 12:
      case 13:
        char2 = str.charCodeAt(i++)
        out += String.fromCharCode(((c & 0x1f) << 6) | (char2 & 0x3f))
        break
      case 14:
        char2 = str.charCodeAt(i++)
        char3 = str.charCodeAt(i++)
        out += String.fromCharCode(
          ((c & 0x0f) << 12) | ((char2 & 0x3f) << 6) | ((char3 & 0x3f) << 0)
        )
        break
    }
  }
  return out
}

四：ArrayBuffer转base64
如果在小程序中使用 需引入 base64js.js

const toBase64 = (buffer : any, type) => {
var binary = ''
	var bytes = new Uint8Array(buffer)
	var len = bytes.byteLength
	for (var i = 0; i < len; i++) {
		binary += String.fromCharCode(bytes[i])
	}
	return window.btoa(binary)
}