基于LM的（GB28181/EHOME）设备语音指挥（对讲、广播）

简介

LM视频中间音频对讲和广播，支持一对一、一对多、多对多、控制前端播放自定wav语音文件及创建语音聊天室等功能，可基于基础安防设备实现实时多方语音通话、语音喊话及报警联动语音播放等场景下语音交互。

LM视频中间件支持的设备如下：

全系列海康设备
全系列大华设备
GB28181设备（内网UDP/TCP，外网TCP模式）
EHOME协议设备，包含ISUP

LM主要对外开放接口有，开启对讲（广播）、关闭对讲（广播）、发送语音和发送wav文件播放等，详细API说明见API说明文档

提示
需设备上安装了麦克风和喇叭

API接口说明

开启对讲(广播)

此接口为开启或加入对讲(组)，其中请求参数

deviceId 可以为空时，为用户发起新建（加入）对讲组，本次请求不添加新的设备到对讲组中
ssid为0时，代表新建对讲（广播）组，当ssid不为0时为加入已存在的对讲组，ssid对讲组必须要存在，否则会返回对讲组不存在的错误

注：

用户创建对讲组后，若在一段时间内（15秒）不调用发送语音或者播放wav文件接口，LM将自动释放当前对讲组，同时关闭和前端设备之间的对讲会话。
如对讲的设备已被对讲组占用，LM会在接口返回User Already Opening错误，调用者可以在接口返回的数组详情中得到占用设备得对讲组ssid，从而再发起加入对讲组得请求进行语音通讯。

请求

POST /api/v1/talk/start?token=f384932b-92b9-4947-a567-10c33a82b44f HTTP/1.1
Content-Type: application/json
Accept: */*
Accept-Encoding: gzip, deflate, br
Connection: keep-alive
Content-Length: 63{"ssid":0,"deviceId":["A20221214135512","A123445"]
}

应答
返回的信息需要到detail数组中获取每个设备的开启结果

HTTP/1.1 200 OK
Content-Type: application/json
Content-Length: 177
Connection: keep-alive
Access-Control-Allow-Origin: *{"result": 200,"message": "OK","ssid": 1,"detail": [{"deviceId": "A20221214135512","result": "OK"},{"deviceId": "A123445","result": "Invalid Device ID"}]
}

关闭对讲（广播）

此接口为关闭对讲组接口,使用时也可以不调用此接口，LM也会自动检测是否还存在用户存在对讲组中，接口参数

deviceId为空时关闭参数ssid指定的对讲组
ssId为非0且LM中必须存在此对讲组

请求

    POST /api/v1/talk/stop?token=8305918c-69e8-4280-ae22-85aa5d696e0e HTTP/1.1Content-Type: application/jsonAccept: */*Host: 192.168.3.23:9030Accept-Encoding: gzip, deflate, brConnection: keep-aliveContent-Length: 20{"ssid":636}

!!! sample “应答”

    HTTP/1.1 200 OKContent-Type: application/jsonContent-Length: 42Connection: keep-aliveAccess-Control-Allow-Origin: *{"result": 200,"message": "OK"}

发送语音

此接口是在打开对讲接口调用成功后返回后，客户端使用websocket发送本地及采集的PCM语音数据，语音采样率：44000，采样位为16，单通道。

播放wav文件

本接口仅支持WAV格式的PCM语音文件

网页H5音频采集

网页音频采用使用的是HTML5的getUserMedia API，getUserMedia API为用户提供访问硬件设备媒体（摄像头、视频、音频、地理位置等）的接口，基于该接口，开发者可以在不依赖任何浏览器插件的条件下访问硬件媒体设备。getUserMedia API的浏览器兼容行如图示：

注意
需要网页H5支持采集音频有以下两种方式（以Chrome浏览器为例子）：

服务器端开启https
浏览本地设置例外，进入浏览器本地设置
- 地址栏输入chrome://flags/
- 在设置页面找到选项Insecure origins treated as secure，添加例外服务器地址，重启浏览器即可在开发环境采集音频

采集音频

 initTalk(){// 初始化多媒体对象if (!navigator.mediaDevices.getUserMedia) {alert('浏览器不支持音频输入');} else if(this.record == null){navigator.mediaDevices.getUserMedia = navigator.mediaDevices.getUserMedia || navigator.mediaDevices.webkitGetUserMedia;navigator.mediaDevices.getUserMedia({audio: true}).then((mediaStream)=> {this.record = new this.getRecorder(mediaStream)})}}
getRecorder(stream){let sampleBits = 16;//输出采样数位 8, 16let sampleRate = 44100;//输出采样率let bufSize = 8192;let context = new AudioContext();let audioInput = context.createMediaStreamSource(stream);let recorder = context.createScriptProcessor(0, 1, 1);let audio_resample = new Resampler(context.sampleRate, sampleRate, 1, bufSize);console.log(audio_resample);let audioData = {size: 0,          //录音文件长度buffer: [],    //录音缓存inputSampleRate: sampleRate,    //输入采样率inputSampleBits: 16,      //输入采样数位 8, 16outputSampleRate: sampleRate,oututSampleBits: sampleBits,clear: function () {audioData.buffer = [];audioData.size = 0;},input: function (data) {audioData.buffer.push(new Float32Array(data));audioData.size += data.length;},compress: function () { //合并压缩//合并let data = new Float32Array(this.size);let offset = 0;for (let i = 0; i < this.buffer.length; i++) {data.set(this.buffer[i], offset);offset += this.buffer[i].length;}//压缩let compression = parseInt(this.inputSampleRate / this.outputSampleRate);let length = data.length / compression;let result = new Float32Array(length);let index = 0, j = 0;while (index < length) {result[index] = data[j];j += compression;index++;}return result;},encodePCM: function () {//这里不对采集到的数据进行其他格式处理，如有需要均交给服务器端处理。let sampleRate = Math.min(this.inputSampleRate, this.outputSampleRate);let sampleBits = Math.min(this.inputSampleBits, this.oututSampleBits);let bytes = this.compress();let dataLength = bytes.length * (sampleBits / 8);let buffer = new ArrayBuffer(dataLength);let data = new DataView(buffer);let offset = 0;for (let i = 0; i < bytes.length; i++, offset += 2) {let s = Math.max(-1, Math.min(1, bytes[i]));data.setInt16(offset, s < 0 ? s * 0x8000 : s * 0x7FFF, true);}return new Blob([data]);}};this.start = function () {audioInput.connect(recorder);recorder.connect(context.destination);}this.stop = function () {recorder.disconnect();}this.getBlob = function () {return audioData.encodePCM();}this.clear = function () {audioData.clear();}recorder.onaudioprocess = function (e) {//audioData.input(e.inputBuffer.getChannelData(0));audioData.input(audio_resample.resample(e.inputBuffer.getChannelData(0)));}}getTalkStart(){this.initTalk()if(this.talkOpen){ // this.talkOpen为true开启对讲let data = {deviceId: [this.orgId],ssid: 0};talkStartServe(data,this.getToken()).then(res => {if(res.result==200 && res.ssid != 0) {this.ssid = res.ssidthis.imgSrc = require('@/assets/img/yj-open.png')this.$message.success('设备对讲已开启')this.talkOpen = falsethis.sendTalk()}else {if(res.detail[0] != undefined){if(res.detail[0].result == "User Opened Talking"){this.ssid = res.detail[0].ssidthis.imgSrc = require('@/assets/img/yj-open.png')this.$message.success('设备对讲已开启')this.talkOpen = falsethis.sendTalk()}else{this.$message.error(res.detail[0].result)this.imgSrc = require('@/assets/img/yunjing.png')this.talkOpen = true}}else{this.$message.error("对讲打开失败");this.imgSrc = require('@/assets/img/yunjing.png')this.talkOpen = true}}})}else { // 关闭对讲if(this.record != null){this.record.stop();}if(this.socket != null){this.socket.close();}if(this.pcmPlayer != null){this.pcmPlayer.destroy();this.pcmPlayer = null;} //不需要关闭，后台会根据连接自动关闭对讲组this.$message.success('设备对讲已关闭')this.imgSrc = require('@/assets/img/yunjing.png')this.talkOpen = true/*talkStopServe({ssid: this.ssid},this.getToken()).then(res => {if(res.result==200) {this.$message.success('设备对讲已关闭')this.imgSrc = require('@/assets/img/yunjing.png')this.talkOpen = true}else {this.$message.error('操作失败')this.imgSrc = require('@/assets/img/yj-open.png')this.talkOpen = false}})*/}}

发送音频

 sendTalk() {// WebSocket发送音频let that = this // this指向会有问题that代替let locUrl = window.location.hostlet stemp = '';if(window.location.protocol === 'https:'){stemp ='s';}const socketUrl = 'ws' + stemp +'://'+ locUrl + '/ws_talk/'+this.ssid+'?token='+this.getToken();// + '&sampleRate=' + this.context.sampleRate;that.socket = new WebSocket(socketUrl)that.socket.binaryType = 'arraybuffer'that.socket.onopen = function () {console.log('浏览器WebSocket已打开');if(that.record != null){that.record.start();}else{console.log('声音采集打开失败');}    window.timeInte = setInterval(() => {if(that.socket != null && that.socket.readyState == 1) {if (that.record != null && that.record.getBlob().size != 0) {that.socket.send(that.record.getBlob());    //发送音频数据that.record.clear();}}},20)};if(that.pcmPlayer == null){that.pcmPlayer = new PCMPlayer({inputCodec: 'Int16',channels: 1,sampleRate: 16000,flushTime: 200})}that.socket.onmessage = function(msg) {// 接收WebSocket消息that.pcmPlayer.feed(msg.data)}}

常见错误码

result	message	说明
200	OK	成功
400	device not find	设备不存在
400	audio file format not support	音频格式不支持
400	talk session not find	对讲组不存在
403	limit license	授权限制
423	invalid server	服务错误或授权到期
424	user not login	用户未登录
	User Opened Talking	设备已打开设备对讲
	RTSP Disconnect	设备对讲打开失败