我有一些UTF-8编码的数据生活在Javascript Uint8Array元素的范围内。是否有一种有效的方法来解码这些到一个常规的javascript字符串(我相信javascript使用16位Unicode)?我不想一次添加一个字符,因为字符串连接会变得CPU密集。
当前回答
做什么@Sudhir说,然后得到一个字符串,逗号分隔的数字列表使用:
for (var i=0; i<unitArr.byteLength; i++) {
myString += String.fromCharCode(unitArr[i])
}
这会给你想要的字符串, 如果还相关的话
其他回答
试试这些函数,
var JsonToArray = function(json)
{
var str = JSON.stringify(json, null, 0);
var ret = new Uint8Array(str.length);
for (var i = 0; i < str.length; i++) {
ret[i] = str.charCodeAt(i);
}
return ret
};
var binArrayToJson = function(binArray)
{
var str = "";
for (var i = 0; i < binArray.length; i++) {
str += String.fromCharCode(parseInt(binArray[i]));
}
return JSON.parse(str)
}
来源:https://gist.github.com/tomfa/706d10fed78c497731ac,向Tomfa致敬
在节点“缓冲区实例也是Uint8Array实例”,所以buf.toString()在这种情况下工作。
在NodeJS中,我们有缓冲区可用,使用它们进行字符串转换非常容易。更好的是,它很容易将Uint8Array转换为Buffer。试试这段代码,它为我在节点基本上任何转换涉及Uint8Arrays:
let str = Buffer.from(uint8arr.buffer).toString();
我们只是从Uint8Array中提取ArrayBuffer,然后将其转换为适当的NodeJS Buffer。然后我们将Buffer转换为一个字符串(如果你愿意,你可以使用十六进制或base64编码)。
如果我们想从一个字符串转换回Uint8Array,那么我们会这样做:
let uint8arr = new Uint8Array(Buffer.from(str));
注意,如果你在转换为字符串时声明了一个像base64这样的编码,那么如果你使用base64或任何其他你使用的编码,你就必须使用Buffer.from(str, "base64")。
这将在没有模块的浏览器中不起作用!NodeJS的Buffer在浏览器中是不存在的,所以除非你在浏览器中添加Buffer功能,否则这个方法是行不通的。这其实很容易做到,只要使用像这样的模块,它既小又快!
对于香草,浏览器端,从麦克风录音,base64函数为我工作(我必须实现一个音频发送功能到聊天)。
const ui8a = new Uint8Array(e.target.result);
const string = btoa(ui8a);
const ui8a_2 = atob(string).split(',');
现在是完整代码。感谢Bryan Jennings & breakspirit@py4u.net提供的代码。
https://medium.com/@bryanjenningz/how-to-record-and-play-audio-in-javascript-faa1b2b3e49b
https://www.py4u.net/discuss/282499
index . html
<html>
<head>
<title>Record Audio Test</title>
<meta name="encoding" charset="utf-8" />
</head>
<body>
<h1>Audio Recording Test</h1>
<script src="index.js"></script>
<button id="action" onclick="start()">Start</button>
<button id="stop" onclick="stop()">Stop</button>
<button id="play" onclick="play()">Listen</button>
</body>
</html>
index.js:
const recordAudio = () =>
new Promise(async resolve => {
const stream = await navigator.mediaDevices.getUserMedia({ audio: true });
const mediaRecorder = new MediaRecorder(stream);
const audioChunks = [];
mediaRecorder.addEventListener("dataavailable", event => {
audioChunks.push(event.data);
});
const start = () => mediaRecorder.start();
const stop = () =>
new Promise(resolve => {
mediaRecorder.addEventListener("stop", () => {
const audioBlob = new Blob(audioChunks);
const audioUrl = URL.createObjectURL(audioBlob);
const audio = new Audio(audioUrl);
const play = () => audio.play();
resolve({ audioBlob, audioUrl, play });
});
mediaRecorder.stop();
});
resolve({ start, stop });
});
let recorder = null;
let audio = null;
const sleep = time => new Promise(resolve => setTimeout(resolve, time));
const start = async () => {
recorder = await recordAudio();
recorder.start();
}
const stop = async () => {
audio = await recorder.stop();
read(audio.audioUrl);
}
const play = ()=> {
audio.play();
}
const read = (blobUrl)=> {
var xhr = new XMLHttpRequest;
xhr.responseType = 'blob';
xhr.onload = function() {
var recoveredBlob = xhr.response;
const reader = new FileReader();
// This fires after the blob has been read/loaded.
reader.addEventListener('loadend', (e) => {
const ui8a = new Uint8Array(e.target.result);
const string = btoa(ui8a);
const ui8a_2 = atob(string).split(',');
playByteArray(ui8a_2);
});
// Start reading the blob as text.
reader.readAsArrayBuffer(recoveredBlob);
};
// get the blob through blob url
xhr.open('GET', blobUrl);
xhr.send();
}
window.onload = init;
var context; // Audio context
var buf; // Audio buffer
function init() {
if (!window.AudioContext) {
if (!window.webkitAudioContext) {
alert("Your browser does not support any AudioContext and cannot play back this audio.");
return;
}
window.AudioContext = window.webkitAudioContext;
}
context = new AudioContext();
}
function playByteArray(byteArray) {
var arrayBuffer = new ArrayBuffer(byteArray.length);
var bufferView = new Uint8Array(arrayBuffer);
for (i = 0; i < byteArray.length; i++) {
bufferView[i] = byteArray[i];
}
context.decodeAudioData(arrayBuffer, function(buffer) {
buf = buffer;
play2();
});
}
// Play the loaded file
function play2() {
// Create a source node from the buffer
var source = context.createBufferSource();
source.buffer = buf;
// Connect to the final output node (the speakers)
source.connect(context.destination);
// Play immediately
source.start(0);
}
到目前为止,对我来说最简单的方法是:
//1. Create or fetch the Uint8Array to use in the example
const bufferArray = new Uint8Array([10, 10, 10])
//2. Turn the Uint8Array into a regular array
const array = Array.from(bufferArray);
//3. Stringify it (option A)
JSON.stringify(array);
//3. Stringify it (option B: uses @serdarsenay code snippet to decode each item in array)
let binArrayToString = function(binArray) {
let str = "";
for (let i = 0; i < binArray.length; i++) {
str += String.fromCharCode(parseInt(binArray[i]));
}
return str;
}
binArrayToString(array);
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