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159 | "use strict";
const mediaPort = "8890";
const retryDelay = 1000;
const freezeAfter = 5000;
const watchdogEvery = 1000;
const video = document.getElementById("video");
const statusLabel = document.getElementById("status-label");
const stateTitle = document.getElementById("state-title");
const stateDetail = document.getElementById("state-detail");
const stateCopy = {
connecting: ["Connecting", "Waiting for the camera stream"],
offline: ["Camera offline", "Retrying automatically…"],
};
const mediaBase = new URL(window.location.href);
mediaBase.port = mediaPort;
mediaBase.pathname = "/crib/";
mediaBase.search = "";
mediaBase.hash = "";
let reader = null;
let reconnectTimer = null;
let frameCallback = null;
let lastFrameAt = 0;
let stopped = false;
function setState(next) {
const copy = stateCopy[next];
document.body.dataset.state = next;
video.controls = next === "live";
statusLabel.textContent = next;
if (copy) {
[stateTitle.textContent, stateDetail.textContent] = copy;
}
}
function clearVideo() {
video.pause();
video.srcObject = null;
}
function scheduleReconnect(reason) {
if (stopped) {
return;
}
console.warn(`[cribd] ${reason}`);
reader?.close();
reader = null;
clearVideo();
setState("offline");
clearTimeout(reconnectTimer);
reconnectTimer = window.setTimeout(connect, retryDelay);
}
function loadReader() {
if (window.MediaMTXWebRTCReader !== undefined) {
return Promise.resolve();
}
return new Promise((resolve, reject) => {
const script = document.createElement("script");
script.src = new URL("reader.js", mediaBase).toString();
script.onload = () => {
if (window.MediaMTXWebRTCReader === undefined) {
reject(new Error("MediaMTX reader did not load"));
return;
}
resolve();
};
script.onerror = () => {
script.remove();
reject(new Error("MediaMTX reader is unavailable"));
};
document.head.append(script);
});
}
async function connect() {
reconnectTimer = null;
try {
await loadReader();
if (stopped) {
return;
}
reader = new window.MediaMTXWebRTCReader({
url: new URL("whep", mediaBase).toString(),
onError: scheduleReconnect,
onTrack: (event) => {
if (stopped || event.streams.length === 0) {
return;
}
video.srcObject = event.streams[0];
lastFrameAt = performance.now();
video.play().catch(() => undefined);
},
});
} catch (error) {
scheduleReconnect(error);
}
}
function markFrame() {
if (video.srcObject === null) {
return;
}
lastFrameAt = performance.now();
if (document.body.dataset.state !== "live") {
setState("live");
}
}
if (typeof video.requestVideoFrameCallback === "function") {
const onFrame = () => {
markFrame();
frameCallback = video.requestVideoFrameCallback(onFrame);
};
frameCallback = video.requestVideoFrameCallback(onFrame);
} else {
video.addEventListener("timeupdate", markFrame);
}
document.addEventListener("visibilitychange", () => {
if (!document.hidden) {
lastFrameAt = performance.now();
}
});
const watchdog = window.setInterval(() => {
if (
!document.hidden &&
video.srcObject !== null &&
!video.paused &&
performance.now() - lastFrameAt >= freezeAfter
) {
scheduleReconnect("video stopped producing frames");
}
}, watchdogEvery);
window.addEventListener("beforeunload", () => {
stopped = true;
clearTimeout(reconnectTimer);
clearInterval(watchdog);
if (
frameCallback !== null &&
typeof video.cancelVideoFrameCallback === "function"
) {
video.cancelVideoFrameCallback(frameCallback);
}
reader?.close();
});
connect();
|