Piik/scripts/browser-encoded-fanout-probe.mjs

import http from 'node:http';
import { mkdirSync, writeFileSync } from 'node:fs';

// Explicit local experiment, never part of product startup or ordinary CI.
const codec = process.argv.includes('--h264') ? 'H264' : 'VP8';
const lateJoin = process.argv.includes('--late-join');
const limited = process.argv.includes('--limit-secondary');
const limitedPrimary = process.argv.includes('--limit-primary');
const requestKeyframe = process.argv.includes('--request-keyframe');
const ordinary = process.argv.includes('--ordinary');
const standard = process.argv.includes('--standard');
const cloneOwn = process.argv.includes('--clone-own');
const durationMs = limitedPrimary ? 14000 : 7000;
const suffix = (lateJoin ? '-late' : '') + (limited ? '-limited' : '') +
  (limitedPrimary ? '-primary-limited' : '') + (requestKeyframe ? '-key' : '') + (ordinary ? '-ordinary' : '') +
  (standard ? '-standard' : '') + (cloneOwn ? '-clone-own' : '');
const worker = `const writers=new Map();
self.onrtctransform=event=>{
  const {readable,writable,options}=event.transformer;
  const writer=writable.getWriter();writers.set(options.name,writer);
  readable.pipeTo(new WritableStream({async write(frame){
    if(options.name!=='A')return;
    const copy=new RTCEncodedVideoFrame(frame);
    await writer.write(${cloneOwn ? 'new RTCEncodedVideoFrame(frame)' : 'frame'});
    if(writers.has('B'))await writers.get('B').write(copy);
  }})).catch(error=>self.postMessage({error:error.name+': '+error.message}));
};`;
mkdirSync('build/encoder-pool', { recursive: true });
const html = `<!doctype html><meta charset="utf-8"><title>Encoded fanout probe</title>
<canvas id="source" width="640" height="360"></canvas>
<video id="a" autoplay muted playsinline></video><video id="b" autoplay muted playsinline></video>
<pre id="result">starting</pre><script>
const pc = [], tracks = [], errors = [];
const transformWorker=${standard ? "new Worker('/worker.js')" : 'null'};
if(transformWorker)transformWorker.onmessage=event=>{if(event.data.error)errors.push(event.data.error);};
let drawing = true, frame = 0, sharedFrames = 0, dummyFrames = 0;
let primaryKeys = 0, joined = false, waitingKey = ${requestKeyframe}, connectedAt = null, firstDecodedMs = null;
document.querySelector('#b').requestVideoFrameCallback(() => {
  if (connectedAt !== null) firstDecodedMs = performance.now() - connectedAt;
});
const wait = ms => new Promise(r => setTimeout(r, ms));
const source = document.querySelector('#source');
const ctx = source.getContext('2d');
function draw() {
  ctx.fillStyle = '#162b38'; ctx.fillRect(0,0,640,360);
  ctx.fillStyle = '#58cf94'; ctx.fillRect((frame * 6) % 580,70,60,180);
  ctx.fillStyle = '#ffb94a'; ctx.font = '42px sans-serif'; ctx.fillText(String(frame++),30,50);
  if (drawing) requestAnimationFrame(draw);
}
draw();
function gather(connection) {
  if (connection.iceGatheringState === 'complete') return Promise.resolve();
  return new Promise((resolve,reject) => {
    const timer=setTimeout(()=>reject(Error('ICE gathering deadline')),5000);
    connection.addEventListener('icegatheringstatechange',()=>{
      if(connection.iceGatheringState==='complete'){ clearTimeout(timer); resolve(); }
    });
  });
}
function connected(connection) {
  if (connection.connectionState === 'connected') return Promise.resolve();
  return new Promise((resolve,reject) => {
    const listener=()=>{if(connection.connectionState==='connected'){clearTimeout(timer);connection.removeEventListener('connectionstatechange',listener);resolve();}};
    const timer=setTimeout(()=>{connection.removeEventListener('connectionstatechange',listener);reject(Error('connection deadline'));},5000);
    connection.addEventListener('connectionstatechange',listener);
  });
}
async function pair(track,video,name) {
  const send=new RTCPeerConnection({encodedInsertableStreams:${!standard},iceServers:[]});
  const receive=new RTCPeerConnection({iceServers:[]}); pc.push(send,receive);
  receive.ontrack=e=>{video.srcObject=new MediaStream([e.track]); video.play().catch(()=>{});};
  const sender=send.addTrack(track,new MediaStream([track]));
  send.getTransceivers()[0].setCodecPreferences(RTCRtpSender.getCapabilities('video').codecs.filter(c=>c.mimeType==='video/${codec}'));
  const streams=${standard ? "null;sender.transform=new RTCRtpScriptTransform(transformWorker,{name})" : 'sender.createEncodedStreams()'};
  return {send,receive,sender,streams,async connect(){
    await send.setLocalDescription(await send.createOffer()); await gather(send);
    await receive.setRemoteDescription(send.localDescription);
    await receive.setLocalDescription(await receive.createAnswer()); await gather(receive);
    await send.setRemoteDescription(receive.localDescription);
  }};
}
async function stats(connection) {
  return [...(await connection.getStats()).values()].filter(s=>(s.type==='inbound-rtp'||s.type==='outbound-rtp'||s.type==='remote-outbound-rtp')&&s.kind==='video').map(s=>{
    const keys=['type','framesEncoded','framesDecoded','framesSent','framesReceived','frameWidth','frameHeight','framesPerSecond','bytesSent','bytesReceived','totalEncodeTime','qualityLimitationReason','targetBitrate','pliCount','nackCount','reportsSent','remoteTimestamp','encoderImplementation','powerEfficientEncoder'];
    return Object.fromEntries(keys.filter(k=>s[k]!==undefined).map(k=>[k,s[k]]));
  });
}
async function run() {
  if(${standard ? "!globalThis.RTCRtpScriptTransform" : "!RTCRtpSender.prototype.createEncodedStreams"}) throw Error('requested transform unavailable');
  const stream=source.captureStream(30);const main=stream.getVideoTracks()[0];main.contentHint='motion';tracks.push(main);
  const dummy=document.createElement('canvas');dummy.width=dummy.height=16;
  dummy.getContext('2d').fillRect(0,0,16,16);
  const dummyTrack=${ordinary ? "main.clone()" : "dummy.captureStream(0).getVideoTracks()[0]"}; dummyTrack.contentHint='motion';tracks.push(dummyTrack);
  const A=await pair(main,document.querySelector('#a'),'A');
  const B=await pair(dummyTrack,document.querySelector('#b'),'B');
  ${limited ? "const parameters=B.sender.getParameters();parameters.encodings[0].maxBitrate=50000;await B.sender.setParameters(parameters);" : ''}
  ${limitedPrimary ? "const primaryParameters=A.sender.getParameters();primaryParameters.encodings[0].maxBitrate=50000;await A.sender.setParameters(primaryParameters);" : ''}
  let readerA,readerB,pumpA,pumpB;
  if(!${standard}){
  const writerA=A.streams.writable.getWriter(),writerB=B.streams.writable.getWriter();
  readerA=A.streams.readable.getReader();readerB=B.streams.readable.getReader();
  pumpA=(async()=>{for(;;){const r=await readerA.read();if(r.done)return;if(r.value.type==='key')primaryKeys++;const copy=new RTCEncodedVideoFrame(r.value);await writerA.write(r.value);
    if(!${ordinary}&&(!${requestKeyframe}||joined)){if(waitingKey&&copy.type!=='key')continue;waitingKey=false;await writerB.write(copy);sharedFrames++;}
  }})().catch(e=>errors.push(e.message));
  pumpB=(async()=>{for(;;){const r=await readerB.read();if(r.done)return;dummyFrames++;if(${ordinary})await writerB.write(r.value);}})().catch(e=>errors.push(e.message));
  }
  ${lateJoin ? 'await A.connect();await wait(250);await B.connect();' : 'await B.connect();await A.connect();'}
  await connected(B.send);joined=true;connectedAt=performance.now();
  ${requestKeyframe ? "await A.sender.setParameters(A.sender.getParameters(), {encodingOptions:[{keyFrame:true}]});" : ''}
  ${ordinary ? '' : 'dummyTrack.requestFrame();'}
  await wait(${durationMs});
  const result={codec:'${codec}',lateJoin:${lateJoin},ordinary:${ordinary},standard:${standard},cloneOwn:${cloneOwn},requestedKeyframe:${requestKeyframe},primaryKeys,firstDecodedMs,durationMs:${durationMs},
    primaryMaxBitrate:A.sender.getParameters().encodings[0].maxBitrate??null,secondaryMaxBitrate:B.sender.getParameters().encodings[0].maxBitrate??null,browser:navigator.userAgent,sharedFrames,dummyFrames,errors,
    aSend:await stats(A.send),bSend:await stats(B.send),aReceive:await stats(A.receive),bReceive:await stats(B.receive),
    aVideo:[document.querySelector('#a').videoWidth,document.querySelector('#a').videoHeight],
    bVideo:[document.querySelector('#b').videoWidth,document.querySelector('#b').videoHeight]};
  drawing=false;tracks.forEach(t=>t.stop());pc.forEach(p=>p.close());
  if(readerA){await readerA.cancel();await readerB.cancel();await Promise.allSettled([pumpA,pumpB]);}
  transformWorker?.terminate();
  return result;
}
window.probeDone=false;
run().then(async result=>{
  window.probeResult=result;window.probeDone=true;document.querySelector('#result').textContent=JSON.stringify(result,null,2);
  await fetch('/result',{method:'POST',body:JSON.stringify(result)});
}).catch(async e=>{
  drawing=false;tracks.forEach(t=>t.stop());pc.forEach(p=>p.close());
  transformWorker?.terminate();
  window.probeResult={error:e.stack,errors};window.probeDone=true;
  document.querySelector('#result').textContent=JSON.stringify(window.probeResult);
  await fetch('/result',{method:'POST',body:JSON.stringify(window.probeResult)});
});
</script>`;

const timer = setTimeout(()=>server.close(),60000);
const server = http.createServer((req,res)=>{
  if(req.url==='/worker.js'){res.setHeader('content-type','text/javascript');res.end(worker);}
  else if(req.url==='/result'&&req.method==='POST'){
    let data='';req.on('data',chunk=>{data+=chunk;if(data.length>65536)req.destroy();});
    req.on('end',()=>{const result=JSON.parse(data);writeFileSync('build/encoder-pool/browser-fanout-'+codec.toLowerCase()+suffix+'.json',JSON.stringify(result,null,2)+'\n');console.log(JSON.stringify(result));res.end('ok');clearTimeout(timer);server.close();});
  } else {res.setHeader('content-type','text/html');res.end(html);}
});
server.listen(0,'127.0.0.1',()=>console.log('http://127.0.0.1:'+server.address().port));