[TOC] ## 配置參數 ``` var constraints = { video: { width: 640, height: 480, frameRate: 15,//30, // 幀率 // facingMode: "enviroment" // 攝像頭 deviceId: deviceId ? deviceId : undefined // 視頻設備id // 設置之后可以在手機上切換攝像頭 前置后置切換 }, audio: { noiseSuppression: true, //降噪 echoCancellation: true // 回音消除 } } ``` ## 指定設備 > [參考](https://webrtc.github.io/samples/src/content/devices/input-output/) 通過 deviceid 獲取流 ``` // 查詢媒體 navigator.mediaDevices.enumerateDevices() .then((devices) => { devices.forEach((device) => { console.log(`${device.kind}: ${device.label} id = ${device.deviceId}`); }); }) .catch((err) => { console.error(`${err.name}: ${err.message}`); }); // 指定流 const constraints = { audio: {deviceId: audioSource ? {exact: audioSource} : undefined}, video: {deviceId: videoSource ? {exact: videoSource} : undefined} }; navigator.mediaDevices.getUserMedia(constraints).then(gotStream).then(gotDevices).catch(handleError); ```