str0m 0.18.0

WebRTC library in Sans-IO style
Documentation 
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<!DOCTYPE html>
<html>

<head>
    <title>WebRTC Chat example</title>
    <style>
        body {
            background: black;
            color: white;
        }
    </style>
</head>

<body>
    <button id="rtc" onClick="startRtc()">Connect</button>
    <button id="cam" onClick="startCam()" disabled>Cam</button>
    <button id="mic" onClick="startMic()" disabled>Mic</button>
    ICE: <span id="ice_status">new</span>
    <div id="chan_status">Waiting for data channel.</div>
    <div id="media"></div>
    <script>
        let streamCam;
        let streamMic;
        let dataChannel;
        let rtc = new RTCPeerConnection();
        rtc.oniceconnectionstatechange = () => {
            byId('ice_status').innerText = rtc.iceConnectionState;
            if (rtc.iceConnectionState == 'disconnected' || rtc.iceConnectionState == 'failed') {
                if (streamCam) {
                    streamCam.getTracks()[0]?.stop();
                }
                if (streamMic) {
                    streamMic.getTracks()[0]?.stop();
                }
                rtc.close();
                byId('rtc').disabled = true;
                byId('cam').disabled = true;
                byId('mic').disabled = true;
            }
        };
        const byId = (id) => document.getElementById(id);
        const byTag = (tag) => [].slice.call(document.getElementsByTagName(tag));
        var callback = null;
        async function negotiate() {
            const offer = await rtc.createOffer();
            console.log('do offer', offer.sdp.split('\r\n'));
            rtc.setLocalDescription(offer);
            await dataChannel.send(JSON.stringify(offer));
            const json = await new Promise((rs) => {
                callback = rs;
            });
            const answer = JSON.parse(json);
            console.log('received answer', answer.sdp.split('\r\n'));
            rtc.setRemoteDescription(answer);
        }
        async function handleOffer(json) {
            const offer = JSON.parse(json);
            console.log('handle offer', offer.sdp.split('\r\n'));
            rtc.setRemoteDescription(offer);
            const answer = await rtc.createAnswer();
            console.log('offer response', answer.sdp.split('\r\n'));
            rtc.setLocalDescription(answer);
            await dataChannel.send(JSON.stringify(answer));
        }
        async function startCam() {
            byId('cam').disabled = true;
            streamCam = await navigator.mediaDevices.getUserMedia({
                video: {
                    width: 640,
                    height: 360,
                },
            });
            const tr = rtc.addTransceiver(streamCam.getTracks()[0], {
                direction: "sendonly",
                streams: [streamCam],
                // This table shows the valid values for simulcast.
                //
                // https://chromium.googlesource.com/external/webrtc/+/branch-heads/49/talk/media/webrtc/simulcast.cc
                // These tables describe from which resolution we can use how many
                // simulcast layers at what bitrates (maximum, target, and minimum).
                // Important!! Keep this table from high resolution to low resolution.
                // const SimulcastFormat kSimulcastFormats[] = {
                //   {1920, 1080, 3, 5000, 4000, 800},
                //   {1280, 720, 3,  2500, 2500, 600},
                //   {960, 540, 3, 900, 900, 450},
                //   {640, 360, 2, 700, 500, 150},
                //   {480, 270, 2, 450, 350, 150},
                //   {320, 180, 1, 200, 150, 30},
                //   {0, 0, 1, 200, 150, 30}
                // };

                // Uncomment this to enable simulcast. The actual selected
                // simulcast level is hardcoded in chat.rs.
                // sendEncodings: [
                //     { rid: "h", maxBitrate: 700 * 1024 },
                //     { rid: "l", maxBitrate: 150 * 1024 }
                // ]
            });
            await negotiate();
        }
        async function startMic() {
            byId('mic').disabled = true;
            streamMic = await navigator.mediaDevices.getUserMedia({
                audio: true,
            });
            const tr = rtc.addTransceiver(streamMic.getTracks()[0], {
                streams: [streamMic],
                direction: "sendonly"
            });
            await negotiate();
        }
        rtc.ontrack = (e) => {
            console.log('ontrack', e.track);
            const track = e.track;
            const domId = `media-${track.id}`;
            const el = document.createElement('video');
            if (byId(domId)) {
                // we aleady have this track
                return;
            }
            el.id = domId;
            el.width = 500;
            byId('media').appendChild(el);
            el.controls = true;
            el.autoplay = true;
            setTimeout(() => {
                const media = new MediaStream();
                media.addTrack(track);
                el.srcObject = media;
            }, 1);
            track.addEventListener('mute', () => {
                console.log('track muted', track);
                el.parentNode.removeChild(el);
            });
            track.addEventListener('unmute', () => {
                console.log('track unmuted', track);
                byId('media').appendChild(el);
            });
        };
        async function startRtc() {
            byId('rtc').disabled = true;
            dataChannel = rtc.createDataChannel("offer/answer");
            dataChannel.onmessage = (event) => {
                let json = JSON.parse(event.data);
                if (json.type == 'offer') {
                    // no callback probably means it's an offer
                    handleOffer(event.data);
                } else if (json.type == 'answer') {
                    callback(event.data);
                    callback = null;
                }
            };
            dataChannel.onopen = () => {
                byId('chan_status').innerText = '';
                byId('mic').disabled = false;
                byId('cam').disabled = false;
            };
            const offer = await rtc.createOffer();
            rtc.setLocalDescription(offer);
            console.log('POST offer', offer.sdp.split('\r\n'));

            const res = await fetch('/start', {
                method: 'POST',
                headers: {
                    'Content-Type': 'application/json'
                },
                body: JSON.stringify(offer),
            });

            const answer = await res.json();
            rtc.setRemoteDescription(answer);
            console.log('POST answer', answer.sdp.split('\r\n'));
        }
    </script>
</body>

</html>