前言

最近接到一个需求，实现录音功能并生成mp3文件到本地工作区，一开始考虑到的是在vscode主体代码里面开发，但这可不是一个小的工作量。时间紧，任务重！市面上实现录音功能的案例其实很多，一些功能代码是可以复用过来的，最后决定写一个插件去实现这个需求！但是插件页面是浏览器环境，想要生成mp3文件是不可能的！需要把语音数据传到node环境。

以目前的vscode版本来说，作者并没有开放访问本地媒体权限，所以插件市场里面的所有语音相关插件也并没有直接获取vscode的媒体权限。毕竟vscode是开源项目，有广大的插件市场，如果开放了所有权限，遇到了图谋不轨的人 ，想通过插件获取你的个人信息很容易，比如打开你的麦克风 打开你的摄像头 获取地理定位，在你不经意间可能就获取了你的个人信息，所以作者对权限做了限制。 这样如果想单纯通过写插件调用本地媒体设备的同学，可以放弃你的想法了。

对于一些二次开发的同学则很容易，在主体代码里面放开对应权限。
这里我们主要讲下 插件实现：

对应目录结构，主要文件

本地录音及生成mp3文件

对应demo页面

wavesurfer.js ->实现 声纹图、声谱图、播放录音
lame.min.js -> mp3编码器
record.js的 -> 实现录音

这几个文件github有很多例子，大同小异，核心api都是一样的
初始化

我们再了解几个js关于语音的api
navigator.getUserMedia: 该对象可提供对相机和麦克风等媒体输入设备的连接访问，也包括屏幕共享。
AudioContext: 接口表示由链接在一起的音频模块构建的音频处理图，每个模块由一个AudioNode表示。音频上下文控制它包含的节点的创建和音频处理或解码的执行。在做任何其他操作之前，您需要创建一个AudioContext对象，因为所有事情都是在上下文中发生的。建议创建一个AudioContext对象并复用它，而不是每次初始化一个新的AudioContext对象，并且可以对多个不同的音频源和管道同时使用一个AudioContext对象。
createMediaStreamSource: 方法用于创建一个新的 MediaStreamAudioSourceNode 对象，需要传入一个媒体流对象 (MediaStream 对象)(可以从 navigator.getUserMedia 获得 MediaStream 对象实例), 然后来自 MediaStream 的音频就可以被播放和操作。
createScriptProcessor: 处理音频。
onaudioprocess: 监听音频录制过程,实时获取语音流

页面

mounted() {
	this.wavesurfer = WaveSurfer.create({
		container: '#waveform',
		waveColor: 'black',
		interact: false,
		cursorWidth: 1,
		barWidth: 1,
		plugins: [
			WaveSurfer.microphone.create()
		]
	});

	this.wavesurfer.microphone.on('deviceReady', function (stream) {
		console.log('Device ready!', stream);
	});
	this.wavesurfer.microphone.on('deviceError', function (code) {
		console.warn('Device error: ' + code);
	});

	this.recorder = new Recorder({
		sampleRate: 44100, //采样频率，默认为44100Hz(标准MP3采样率)
		bitRate: 128, //比特率，默认为128kbps(标准MP3质量)
		success: function() { //成功回调函数
			console.log('success-->')
			// start.disabled = false;
		},
		error: function(msg) { //失败回调函数
			alert('msg-->', msg);
		},
		fix: function(msg) { //不支持H5录音回调函数
			alert('msg--->', msg);
		}
	});
}

点击开始和结束录音

start() {
	// start the microphone
	this.wavesurfer.microphone.start();
	// 开始录音
	this.recorder.start();
},
end() {
	// same as stopDevice() but also clears the wavesurfer canvas
	this.wavesurfer.microphone.stop();
	// 结束录音
	this.recorder.stop();
	let that = this;
	this.recorder.getBlob(function(blob) {
		that.audioPath = URL.createObjectURL(blob);
		that.$refs.myAudio.load();
	});
}

recorder.js

//初始化
init: function () {
	navigator.getUserMedia = navigator.getUserMedia ||
		navigator.webkitGetUserMedia ||
		navigator.mozGetUserMedia ||
		navigator.msGetUserMedia;

	window.AudioContext = window.AudioContext ||
		window.webkitAudioContext;
},

// 访问媒体设备
navigator.getUserMedia({
		audio: true //配置对象
	},
function (stream) { //成功回调
	var context = new AudioContext(),
		microphone = context.createMediaStreamSource(stream), //媒体流音频源
		processor = context.createScriptProcessor(0, 1, 1), //js音频处理器
	}
})		

// 开始录音
_this.start = function () {
	if (processor && microphone) {
		microphone.connect(processor);
		processor.connect(context.destination);
		Util.log('开始录音');
	}
};

//结束录音
_this.stop = function () {
	if (processor && microphone) {
		microphone.disconnect();
		processor.disconnect();
		Util.log('录音结束');
	}
};

// new worker 开启后台线程，为数据编码，这里我部署到线上 是为了避免访问限制
fetch(
		"https://lawdawn-download.oss-cn-beijing.aliyuncs.com/js/recorderWorker.js"
	)
		.then((response) => response.blob())
		.then((blob) => {
			const url = URL.createObjectURL(blob);
			realTimeWorker = new Worker(url);
			realTimeWorker.onmessage = async function (e) {
			...
		}
	})	

recorderWorker.js

// 后台线程接受到语音流数据之后做编码
(function(){
    'use strict';

    importScripts('https://lawdawn-download.oss-cn-beijing.aliyuncs.com/js/lame.min.js');

    var mp3Encoder, maxSamples = 1152, samplesMono, lame, config, dataBuffer;

    var clearBuffer = function(){
        dataBuffer = [];
    };

    var appendToBuffer = function(mp3Buf){
        dataBuffer.push(new Int8Array(mp3Buf));
    };

    var init = function(prefConfig){
        config = prefConfig || {};
        lame = new lamejs();
        mp3Encoder = new lame.Mp3Encoder(1, config.sampleRate || 44100, config.bitRate || 128);
        clearBuffer();
        self.postMessage({
            cmd: 'init'
        });
    };

    var floatTo16BitPCM = function(input, output){
        for(var i = 0; i < input.length; i++){
            var s = Math.max(-1, Math.min(1, input[i]));
            output[i] = (s < 0 ? s * 0x8000 : s * 0x7FFF);
        }
    };

    var convertBuffer = function(arrayBuffer){
        var data = new Float32Array(arrayBuffer);
        var out = new Int16Array(arrayBuffer.length);
        floatTo16BitPCM(data, out);
        return out;
    };

    var encode = function(arrayBuffer){
        samplesMono = convertBuffer(arrayBuffer);
        var remaining = samplesMono.length;
        for(var i = 0; remaining >= 0; i += maxSamples){
            var left = samplesMono.subarray(i, i + maxSamples);
            var mp3buf = mp3Encoder.encodeBuffer(left);
            appendToBuffer(mp3buf);
            remaining -= maxSamples;
        }
    };

    var finish = function(){
        appendToBuffer(mp3Encoder.flush());
        self.postMessage({
            cmd: 'end',
            buf: dataBuffer
        });
        clearBuffer();
    };

    self.onmessage = function(e){
        switch(e.data.cmd){
            case 'init':
                init(e.data.config);
                break;
            case 'encode':
                encode(e.data.buf);
                break;
            case 'finish':
                finish();
                break;
        }
    };
})();

整个recorder.js

(function (exports) {
	//公共方法
	var Util = {
		//初始化
		init: function () {
			navigator.getUserMedia = navigator.getUserMedia ||
				navigator.webkitGetUserMedia ||
				navigator.mozGetUserMedia ||
				navigator.msGetUserMedia;

			window.AudioContext = window.AudioContext ||
				window.webkitAudioContext;
		},
		//日志
		log: function () {
			console.log.apply(console, arguments);
		}
	};
	let realTimeWorker;

	var Recorder = function (config) {

		var _this = this;
		config = config || {}; //初始化配置对象
		config.sampleRate = config.sampleRate || 44100; //采样频率，默认为44100Hz(标准MP3采样率)
		config.bitRate = config.bitRate || 128; //比特率，默认为128kbps(标准MP3质量)

		Util.init();

		if (navigator.getUserMedia) {
			navigator.getUserMedia({
				audio: true //配置对象
			},
				function (stream) { //成功回调
					var context = new AudioContext(),
						microphone = context.createMediaStreamSource(stream), //媒体流音频源
						processor = context.createScriptProcessor(0, 1, 1), //js音频处理器
						successCallback, errorCallback;

					config.sampleRate = context.sampleRate;

					processor.onaudioprocess = function (event) {
						//监听音频录制过程
						var array = event.inputBuffer.getChannelData(0);

						realTimeWorker.postMessage({ cmd: 'encode', buf: array });
					};
					fetch(
						"https://lawdawn-download.oss-cn-beijing.aliyuncs.com/js/recorderWorker.js"
					)
						.then((response) => response.blob())
						.then((blob) => {
							const url = URL.createObjectURL(blob);
							realTimeWorker = new Worker(url);
							realTimeWorker.onmessage = async function (e) { //主线程监听后台线程，实时通信
								switch (e.data.cmd) {
									case 'init':
										Util.log('初始化成功');
										if (config.success) {
											config.success();
										}
										break;
									case 'end':
										if (successCallback) {
											var blob = new Blob(e.data.buf, { type: 'audio/mp3' });
											let formData = new FormData();
											formData.append('file', blob, 'main.mp3');
											fetch("http://127.0.0.1:8840/microm", {
												method: 'POST',
												body: formData
											})
											successCallback(blob);
											Util.log('MP3大小：' + blob.size + '%cB', 'color:#0000EE');
										}
										break;
									case 'error':
										Util.log('错误信息：' + e.data.error);
										if (errorCallback) {
											errorCallback(e.data.error);
										}
										break;
									default:
										Util.log('未知信息：' + e.data);
								}
							};
							_this.start = function () {
								if (processor && microphone) {
									microphone.connect(processor);
									processor.connect(context.destination);
									Util.log('开始录音');
								}
							};
							//结束录音
							_this.stop = function () {
								if (processor && microphone) {
									microphone.disconnect();
									processor.disconnect();
									Util.log('录音结束');
								}
							};
							//获取blob格式录音文件
							_this.getBlob = function (onSuccess, onError) {
								successCallback = onSuccess;
								errorCallback = onError;
								realTimeWorker.postMessage({ cmd: 'finish' });
							};

							realTimeWorker.postMessage({
								cmd: 'init',
								config: {
									sampleRate: config.sampleRate,
									bitRate: config.bitRate
								}
							});
						});
					// var realTimeWorker = new Worker('js/recorderWorker.js'); //开启后台线程
					//接口列表
					//开始录音

				},
				function (error) { //失败回调
					var msg;
					switch (error.code || error.name) {
						case 'PermissionDeniedError':
						case 'PERMISSION_DENIED':
						case 'NotAllowedError':
							msg = '用户拒绝访问麦克风';
							break;
						case 'NOT_SUPPORTED_ERROR':
						case 'NotSupportedError':
							msg = '浏览器不支持麦克风';
							break;
						case 'MANDATORY_UNSATISFIED_ERROR':
						case 'MandatoryUnsatisfiedError':
							msg = '找不到麦克风设备';
							break;
						default:
							msg = '无法打开麦克风，异常信息:' + (error.code || error.name);
							break;
					}
					Util.log(msg);
					if (config.error) {
						config.error(msg);
					}
				});
		} else {
			Util.log('当前浏览器不支持录音功能');
			if (config.fix) {
				config.fix('当前浏览器不支持录音功能');
			}
		}

	};
	//模块接口
	exports.Recorder = Recorder;
})(window);

踩坑！

前面录音都进行的很顺利，录音在渲染进程里都可以正常播放，接下来就是生成本地mp3文件的处理了。

第一次尝试：浏览器端获取的Blob数据，通过vscode.postMessage传送过去之后获取的竟是{}空对象。

肯能原因 数据传输过程做了序列化，导致丢失，或者Blob只是浏览器API，node无法获取

第二次尝试：将实时获取的语音数据流传递过去


数据 是Float32Array格式数据，但是通过序列化传递过去之后，发现数据无法恢复原来的样子，还是失败！

经过苦想后接下来，用了一个方法
第三次尝试：
在extension.ts里面开启了一个本地服务

export async function activate(context: vscode.ExtensionContext) {
	(global as any).audioWebview = null;

	context.subscriptions.push(VsAudioEditorProvider.register(context));
	const server = http.createServer((req, res) => {
		res.setHeader('Access-Control-Allow-Origin', '*');
		res.setHeader('Access-Control-Allow-Methods', 'GET, POST, OPTIONS, PUT, PATCH, DELETE');
		res.setHeader('Access-Control-Allow-Headers', 'X-Requested-With,content-type');
		res.setHeader('Access-Control-Allow-Credentials', 'true');
		if (req.method === 'POST' && req.url === '/microm') {
			const stream = fs.createWriteStream(path.join(path.dirname((global as any).documentUri!.fsPath), 'main.mp3'));
			req.on("data", (chunck) => {
				stream.write(chunck);
			});
			req.on("end", () => {
				vscode.window.showInformationMessage('语音文件生成成功！');
				res.writeHead(200);
				res.end('success!');
			});
		}
	}).listen(8840);

}

在浏览器端录音结束后，调用了接口把数据传送了过来

经过在本地和生产环境测试都没有问题～ 大工告成！

语音实时转写功能

语音实时转写调用的科大讯飞的接口，科大讯飞给出的demo页面

js

/**
 * Created by lcw on 2023/5/20.
 *
 * 实时语音转写 WebAPI 接口调用示例 接口文档（必看）：https://www.xfyun.cn/doc/asr/rtasr/API.html
 * 错误码链接：
 * https://www.xfyun.cn/doc/asr/rtasr/API.html
 * https://www.xfyun.cn/document/error-code （code返回错误码时必看）
 *
 */
if (typeof (Worker) == undefined) {
	// 不支持 Web Workers
	alert('不支持 Web Workers');
} else {
	// 支持 Web Workers
	console.log('支持 Web Workers');
}

let recorderWorker

fetch(
	"https://lawdawn-download.oss-cn-beijing.aliyuncs.com/js/transformpcm.worker.js"
)
	.then((response) => response.blob())
	.then((blob) => {
		const url = URL.createObjectURL(blob);
		recorderWorker = new Worker(url);
		recorderWorker.onmessage = function (e) {
			buffer.push(...e.data.buffer)
		}
	});
// 音频转码worker
// let recorderWorker = new Worker('transformpcm.worker.js');
// 记录处理的缓存音频
let buffer = []
let AudioContext = window.AudioContext || window.webkitAudioContext
navigator.getUserMedia = navigator.getUserMedia || navigator.webkitGetUserMedia || navigator.mozGetUserMedia || navigator.msGetUserMedia



class IatRecorder {
	constructor(config) {
		this.config = config
		this.state = 'ing'

		//以下信息在控制台-我的应用-实时语音转写 页面获取
		this.appId = 'xxxxx'
		this.apiKey = 'xxxxx'
	}

	start() {
		this.stop()
		if (navigator.getUserMedia && AudioContext) {
			this.state = 'ing'
			if (!this.recorder) {
				var context = new AudioContext()
				this.context = context
				this.recorder = context.createScriptProcessor(0, 1, 1)

				var getMediaSuccess = (stream) => {
					var mediaStream = this.context.createMediaStreamSource(stream)
					this.mediaStream = mediaStream
					this.recorder.onaudioprocess = (e) => {
						this.sendData(e.inputBuffer.getChannelData(0))
					}
					this.connectWebsocket()
				}
				var getMediaFail = (e) => {
					this.recorder = null
					this.mediaStream = null
					this.context = null
					console.log('请求麦克风失败')
				}
				if (navigator.mediaDevices && navigator.mediaDevices.getUserMedia) {
					navigator.mediaDevices.getUserMedia({
						audio: true,
						video: false
					}).then((stream) => {
						getMediaSuccess(stream)
					}).catch((e) => {
						getMediaFail(e)
					})
				} else {
					navigator.getUserMedia({
						audio: true,
						video: false
					}, (stream) => {
						getMediaSuccess(stream)
					}, function (e) {
						getMediaFail(e)
					})
				}
			} else {
				this.connectWebsocket()
			}
		}
	}

	stop() {
		this.state = 'end'
		try {
			this.mediaStream.disconnect(this.recorder)
			this.recorder.disconnect()
		} catch (e) { }
	}

	sendData(buffer) {
		recorderWorker.postMessage({
			command: 'transform',
			buffer: buffer
		})
	}
	// 生成握手参数
	getHandShakeParams() {
		var appId = this.appId
		var secretKey = this.apiKey
		var ts = Math.floor(new Date().getTime() / 1000);//new Date().getTime()/1000+'';
		var signa = hex_md5(appId + ts)//hex_md5(encodeURIComponent(appId + ts));//EncryptUtil.HmacSHA1Encrypt(EncryptUtil.MD5(appId + ts), secretKey);
		var signatureSha = CryptoJSNew.HmacSHA1(signa, secretKey)
		var signature = CryptoJS.enc.Base64.stringify(signatureSha)
		signature = encodeURIComponent(signature)
		return "?appid=" + appId + "&ts=" + ts + "&signa=" + signature;
	}
	connectWebsocket() {
		// var url = 'wss://rtasr.xfyun.cn/v1/ws'
		var url = 'ws://xxxx.xxx.xx/xf-rtasr';
		var urlParam = this.getHandShakeParams()

		// url = `${url}${urlParam}`
		if ('WebSocket' in window) {
			this.ws = new WebSocket(url)
		} else if ('MozWebSocket' in window) {
			this.ws = new MozWebSocket(url)
		} else {
			alert(notSupportTip)
			return null
		}
		this.ws.onopen = (e) => {
			if (e.isTrusted) {
				this.mediaStream.connect(this.recorder)
				this.recorder.connect(this.context.destination)
				setTimeout(() => {
					this.wsOpened(e)
				}, 500)
				this.config.onStart && this.config.onStart(e)
			} else {
				alert('出现错误');
			}
		}
		this.ws.onmessage = (e) => {
			// this.config.onMessage && this.config.onMessage(e)
			this.wsOnMessage(e)
		}
		this.ws.onerror = (e) => {
			console.log('err-->', e)
			this.stop()
			console.log("关闭连接ws.onerror");
			this.config.onError && this.config.onError(e)
		}
		this.ws.onclose = (e) => {
			this.stop()
			console.log("关闭连接ws.onclose");
			$('.start-button').attr('disabled', false);
			this.config.onClose && this.config.onClose(e)
		}
	}

	wsOpened() {
		if (this.ws.readyState !== 1) {
			return
		}
		var audioData = buffer.splice(0, 1280)
		this.ws.send(new Int8Array(audioData))
		this.handlerInterval = setInterval(() => {
			// websocket未连接
			if (this.ws.readyState !== 1) {
				clearInterval(this.handlerInterval)
				return
			}
			if (buffer.length === 0) {
				if (this.state === 'end') {
					this.ws.send("{"end": true}")
					console.log("发送结束标识");
					clearInterval(this.handlerInterval)
				}
				return false
			}
			var audioData = buffer.splice(0, 1280)
			if (audioData.length > 0) {
				this.ws.send(new Int8Array(audioData))
			}
		}, 40)
	}

	wsOnMessage(e) {
		let jsonData = JSON.parse(e.data)
		// if (jsonData.action == "started") {
		// 	// 握手成功
		// 	console.log("握手成功");
		// } else if (jsonData.action == "result") {
			// 转写结果
			if (this.config.onMessage && typeof this.config.onMessage == 'function') {
				this.config.onMessage(jsonData)
			}
		// } else if (jsonData.action == "error") {
		// 	// 连接发生错误
		// 	console.log("出错了:", jsonData);
		// }
	}


	ArrayBufferToBase64(buffer) {
		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)
	}
}

class IatTaste {
	constructor() {
		var iatRecorder = new IatRecorder({
			onClose: () => {
				this.stop()
				this.reset()
			},
			onError: (data) => {
				this.stop()
				this.reset()
				alert('WebSocket连接失败')
			},
			onMessage: (message) => {
				// this.setResult(JSON.parse(message))
				this.setResult(message)
			},
			onStart: () => {
				$('hr').addClass('hr')
				var dialect = $('.dialect-select').find('option:selected').text()
				$('.taste-content').css('display', 'none')
				$('.start-taste').addClass('flex-display-1')
				$('.dialect-select').css('display', 'none')
				$('.start-button').text('结束转写')
				$('.time-box').addClass('flex-display-1')
				$('.dialect').text(dialect).css('display', 'inline-block')
				this.counterDown($('.used-time'))
			}
		})
		this.iatRecorder = iatRecorder
		this.counterDownDOM = $('.used-time')
		this.counterDownTime = 0

		this.text = {
			start: '开始转写',
			stop: '结束转写'
		}
		this.resultText = ''
	}

	start() {
		this.iatRecorder.start()
	}

	stop() {
		$('hr').removeClass('hr')
		this.iatRecorder.stop()
	}

	reset() {
		this.counterDownTime = 0
		clearTimeout(this.counterDownTimeout)
		buffer = []
		$('.time-box').removeClass('flex-display-1').css('display', 'none')
		$('.start-button').text(this.text.start)
		$('.dialect').css('display', 'none')
		$('.dialect-select').css('display', 'inline-block')
		$('.taste-button').css('background', '#0b99ff')
	}

	init() {
		let self = this
		//开始
		$('#taste_button').click(function () {
			if (navigator.getUserMedia && AudioContext && recorderWorker) {
				self.start()
			} else {
				alert(notSupportTip)
			}
		})
		//结束
		$('.start-button').click(function () {
			if ($(this).text() === self.text.start && !$(this).prop('disabled')) {
				$('#result_output').text('')
				self.resultText = ''
				self.start()
				//console.log("按钮非禁用状态，正常启动" + $(this).prop('disabled'))
			} else {
				//$('.taste-content').css('display', 'none')
				$('.start-button').attr('disabled', true);
				self.stop()
				//reset
				this.counterDownTime = 0
				clearTimeout(this.counterDownTimeout)
				buffer = []
				$('.time-box').removeClass('flex-display-1').css('display', 'none')
				$('.start-button').text('转写停止中...')
				$('.dialect').css('display', 'none')
				$('.taste-button').css('background', '#8E8E8E')
				$('.dialect-select').css('display', 'inline-block')

				//console.log("按钮非禁用状态，正常停止" + $(this).prop('disabled'))
			}
		})
	}
	setResult(data) {
		let rtasrResult = []
		var currentText = $('#result_output').html()
		rtasrResult[data.seg_id] = data
		rtasrResult.forEach(i => {
			let str = "实时转写"
			str += (i.cn.st.type == 0) ? "【最终】识别结果：" : "【中间】识别结果："
			i.cn.st.rt.forEach(j => {
				j.ws.forEach(k => {
					k.cw.forEach(l => {
						str += l.w
					})
				})
			})
			if (currentText.length == 0) {
				$('#result_output').html(str)
			} else {
				$('#result_output').html(currentText + "<br>" + str)
			}
			var ele = document.getElementById('result_output');
			ele.scrollTop = ele.scrollHeight;
		})
	}

	counterDown() {
		/*//计时5分钟
		if (this.counterDownTime === 300) {
			this.counterDownDOM.text('05: 00')
			this.stop()
		} else if (this.counterDownTime > 300) {
			this.reset()
			return false
		} else */
		if (this.counterDownTime >= 0 && this.counterDownTime < 10) {
			this.counterDownDOM.text('00: 0' + this.counterDownTime)
		} else if (this.counterDownTime >= 10 && this.counterDownTime < 60) {
			this.counterDownDOM.text('00: ' + this.counterDownTime)
		} else if (this.counterDownTime % 60 >= 0 && this.counterDownTime % 60 < 10) {
			this.counterDownDOM.text('0' + parseInt(this.counterDownTime / 60) + ': 0' + this.counterDownTime % 60)
		} else {
			this.counterDownDOM.text('0' + parseInt(this.counterDownTime / 60) + ': ' + this.counterDownTime % 60)
		}
		this.counterDownTime++
		this.counterDownTimeout = setTimeout(() => {
			this.counterDown()
		}, 1000)
	}
}
var iatTaste = new IatTaste()
iatTaste.init()

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