二十四、CreatOffer参数实例

基本格式
promis = myPeerConnection.createOffer([options])

Options 可选

• iceRestart：该选项会重启ICE，重新进行Candidate收集
• voiceActivityDetection：是否开启静音检测，默认开启
• 接收远端音频
• 接收远端视频

// let videoPlayer = document.querySelector('video#player');
let creatOffer = document.querySelector('button#createOffer')

let pc = new RTCPeerConnection()
let pc2 = new RTCPeerConnection()

let gotMediaStream = (stream) => {
    stream.getTracks().forEach(track => {
        pc.addTrack(track)
    });

    let options = {
        offerToReceiveAudio: 0,
        offerToReceiveVideo: 1,
        iceRestart: true
    }
    // 媒体协商
    pc.createOffer(options)
        .then((desc) => {
            console.log('offer', desc.sdp)
            pc.setLocalDescription(desc)
            pc2.setRemoteDescription(desc)

            pc2.createAnswer().then((desc) => {
                console.log('answer', desc.sdp)
                pc2.setLocalDescription(desc)
                pc.setRemoteDescription(desc)
            }).catch((err) => {
                console.log(err)
            })
        })
        .catch(() => {
            console.log(err)
        })
}
let handleError = (err) => {
    alert(`getUserMedia errpr:${err}`)
    console.log(`getUserMedia errpr:${err}`)
}

let getStream = () => {
    let constrants = {
        video: {
            width: 640,
            height: 480,
            frameRate: 60,
            facingMode: 'environment',
            resizeMode: 'none'
        },
        audio: false
    }
    navigator.mediaDevices.getUserMedia(constrants)
    .then(gotMediaStream)
    .catch(handleError)
}

creatOffer.onclick = () => {
    if (!pc) {
        console.log('pc is null')
    }
    getStream()
    return
}


if(!navigator.mediaDevices || !navigator.mediaDevices.getUserMedia) {
    alert('getUserMedia is not supported!')
    console.log('getUserMedia is not supported!');
}

当iceRestart为true时，进行两次连接时，会重新收集candidate，a=ice-ufrag会改变