LCDP_web_apps/watch.html at master · kermit4/LCDP_web_apps · GitHub

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<!DOCTYPE html>
<html><head><title>Watch Live Stream</title>
<meta name="viewport" content="width=device-width,initial-scale=1">
<style>
* { box-sizing: border-box; }
body { margin: 0; background: #111; color: #eee; font-family: monospace; }
video { display: block; width: 100%; max-height: 72vh; background: #000; }
#bar { padding: 6px 8px; display: flex; align-items: center; gap: 8px; flex-wrap: wrap; background: #1a1a1a; border-top: 1px solid #333; }
#scrubRow { width: 100%; display: flex; align-items: center; gap: 6px; }
#scrub { flex: 1; cursor: pointer; }
#timeInfo { font-size: 11px; color: #aaa; white-space: nowrap; min-width: 80px; text-align: right; }
#playPos { font-size: 11px; color: #aaa; white-space: nowrap; min-width: 32px; }
button { background: #333; color: #eee; border: 1px solid #555; padding: 4px 10px; cursor: pointer; border-radius: 3px; font-family: monospace; }
button:hover { background: #444; }
#liveBtn { background: #600; border-color: #c44; }
#liveBtn.on { background: #c00; border-color: #f88; animation: pulse 1.5s ease-in-out infinite; }
@keyframes pulse { 0%,100%{opacity:1} 50%{opacity:.65} }
#status { font-size: 11px; color: #888; padding: 3px 8px; }
#setup { padding: 12px; font-size: 13px; }
#setup input { width: 420px; max-width: 90vw; font-family: monospace; background: #222; color: #eee; border: 1px solid #555; padding: 4px; }
#dbg { margin: 6px 8px; padding: 6px; background: #0a0a0a; border: 1px solid #333; font-size: 10px; color: #8f8; min-height: 32px; max-height: 180px; overflow-y: auto; white-space: pre-wrap; word-break: break-all; }
</style>
</head>
<body>
<video id=v controls autoplay playsinline></video>
<div id=bar>
  <button id=liveBtn>&#x25B6; Live</button>
  <div id=scrubRow>
    <span id=playPos>0s</span>
    <input type=range id=scrub min=0 max=0 value=0>
    <span id=timeInfo></span>
  </div>
</div>
<div id=status>Waiting for stream...</div>
<div id=dbg></div>
<div id=setup>
  Stream path: <input id=streamInput placeholder="stream/pubkey/stream-id">
  <button id=loadBtn>Load</button>
  <br><small style="color:#666">or open as watch.html?v=stream/pubkey/stream-id</small>
</div>

<script>
(function() {
    const dbg = document.getElementById('dbg');
    const _log = console.log.bind(console);
    console.log = function(...args) {
        _log(...args);
        const line = args.map(a => typeof a === 'object' ? JSON.stringify(a) : String(a)).join(' ');
        dbg.textContent += line + '\n';
        dbg.scrollTop = dbg.scrollHeight;
    };
    console.log('dbg ready | MSE=' + !!window.MediaSource);
})();

const video     = document.getElementById('v');
const liveBtn   = document.getElementById('liveBtn');
const scrub     = document.getElementById('scrub');
const timeInfo  = document.getElementById('timeInfo');
const playPos   = document.getElementById('playPos');
const statusEl  = document.getElementById('status');
const setup     = document.getElementById('setup');

let mime      = '';   // recorder mime type from cues.json header line
let cues      = [];   // [{o: byteOffset, t: ms from recording start}]
let videoBase = '';   // http://host/stream/pk/id
let cuesUrl   = '';   // videoBase + '.cues.json'
let liveMode  = true;

// MSE state — one MediaSource per playback session (seek creates a new one)
let ms         = null;   // current MediaSource
let sb         = null;   // current SourceBuffer
let sbQueue    = [];     // ArrayBuffers / Uint8Arrays waiting to be appended
let streamCtrl = null;   // AbortController for the current fetch stream

function status(msg) { statusEl.textContent = msg; }

// -- URL / setup ---------------------------------------------------------------
function initFromPath(path) {
    path = path.trim();
    if (!path.startsWith('stream/')) path = 'stream/' + path;
    videoBase = `${location.protocol}//${location.host}/${path}`;
    cuesUrl   = videoBase + '.cues.json';
    document.getElementById('streamInput').value = path.replace(/^stream\//, '');
    setup.hidden = true;
    status('fetching cues...');
    pollCues();
}

(() => {
    const params = new URLSearchParams(location.search);
    const v = params.get('v') || location.hash.replace(/^#/, '');
    if (v) { initFromPath(v); return; }
    setup.hidden = false;
})();

document.getElementById('loadBtn').onclick = () => {
    const v = document.getElementById('streamInput').value.trim();
    if (v) initFromPath(v);
};

// -- Cue polling ---------------------------------------------------------------
// The server keeps the HTTP connection open after sending all available data.
// We detect "end of available data" by aborting 180 ms after the last chunk.
async function fetchCuesText() {
    if (!cuesUrl) return '';
    const ctrl = new AbortController();
    let silenceTimer;
    const resetSilence = () => {
        clearTimeout(silenceTimer);
        silenceTimer = setTimeout(() => ctrl.abort(), 180);
    };
    const chunks = [];
    try {
        const r = await fetch(cuesUrl, { signal: ctrl.signal, cache: 'no-store' });
        if (!r.ok) { ctrl.abort(); return ''; }
        const reader = r.body.getReader();
        resetSilence();
        while (true) {
            const { done, value } = await reader.read().catch(() => ({ done: true }));
            if (done) break;
            chunks.push(value);
            resetSilence();
        }
    } catch(e) { /* AbortError expected */ }
    clearTimeout(silenceTimer);
    if (!chunks.length) return '';
    const total = chunks.reduce((s, c) => s + c.length, 0);
    const all = new Uint8Array(total);
    let pos = 0;
    for (const c of chunks) { all.set(c, pos); pos += c.length; }
    return new TextDecoder().decode(all);
}

function parseCues(text) {
    const newCues = [];
    let newMime = '';
    for (const line of text.split('\n')) {
        // NUL bytes mark the end of written data in the server's zero-padded block
        if (!line || line.charCodeAt(0) === 0) break;
        try {
            const obj = JSON.parse(line);
            if (obj.mime) newMime = obj.mime;
            if (obj.o !== undefined) newCues.push({ o: obj.o, t: obj.t });
        } catch(e) { /* partial last line — ignore */ }
    }
    let changed = false;
    if (newMime && newMime !== mime) { mime = newMime; changed = true; }
    if (newCues.length > cues.length)  { cues = newCues;  changed = true; }
    return changed;
}

async function pollCues() {
    if (!cuesUrl) return;
    try {
        const text = await fetchCuesText();
        if (text && parseCues(text)) onCuesUpdated();
    } catch(e) {}
    setTimeout(pollCues, 2500);
}

function onCuesUpdated() {
    if (!cues.length) return;
    const durSec = cues[cues.length - 1].t / 1000;
    scrub.max = Math.max(0, cues.length - 1);
    timeInfo.textContent = `${durSec.toFixed(0)}s recorded`;
    status(`${cues.length} keyframes  |  ${mime || '...'}`);

    // Keep MS duration in sync as the recording grows
    if (ms && ms.readyState === 'open') {
        try { ms.duration = durSec; } catch(e) {}
    }

    if (liveMode && cues.length >= 2) {
        scrub.value = cues.length - 1;
        if (!ms) playFromCue(cues.length - 1); // initial start; stream loop handles the rest
    }
}

// -- Scrubber / live button ----------------------------------------------------
let scrubActive = false;
scrub.addEventListener('mousedown', () => { scrubActive = true; });
scrub.addEventListener('input', () => {
    liveMode = false;
    liveBtn.classList.remove('on');
    const idx = +scrub.value;
    if (cues[idx]) playPos.textContent = `${(cues[idx].t / 1000).toFixed(0)}s`;
});
scrub.addEventListener('change', () => {
    scrubActive = false;
    const idx = +scrub.value;
    if (cues[idx]) playFromCue(idx);
});

liveBtn.onclick = () => {
    liveMode = true;
    liveBtn.classList.add('on');
    if (cues.length >= 2) {
        scrub.value = cues.length - 1;
        playFromCue(cues.length - 1);
    }
};

video.addEventListener('timeupdate', () => {
    if (scrubActive) return;
    playPos.textContent = `${video.currentTime.toFixed(0)}s`;
    if (liveMode && cues.length) {
        const ms_ = video.currentTime * 1000;
        for (let i = cues.length - 1; i >= 0; i--) {
            if (cues[i].t <= ms_) { scrub.value = i; break; }
        }
    }
});

// -- Find true init-segment boundary ------------------------------------------
// MSE only wants EBML+SeekHead+Info+Tracks — no Cluster data.
// Walk the EBML structure properly so we don't match 1F43B675 inside element
// bodies (e.g. VP9 CodecPrivate data can contain those bytes by coincidence).
function findFirstCluster(buf) {
    const b = new Uint8Array(buf instanceof ArrayBuffer ? buf : buf.buffer, buf.byteOffset || 0);
    const n = b.length;
    function u32(i) { return ((b[i]<<24)|(b[i+1]<<16)|(b[i+2]<<8)|b[i+3])>>>0; }
    // EBML variable-length integer; returns {val, len}, val===-1 means unknown size
    function vint(i) {
        if (i >= n) return null;
        const v = b[i];
        let w, val;
        if      (v&0x80){w=1;val=v&0x7f;        if(val===0x7f)              val=-1;}
        else if (v&0x40){w=2;val=((v&0x3f)<<8)|b[i+1]; if(val===0x3fff)     val=-1;}
        else if (v&0x20){w=3;val=((v&0x1f)<<16)|(b[i+1]<<8)|b[i+2]; if(val===0x1fffff) val=-1;}
        else if (v&0x10){w=4;val=((v&0x0f)<<24)|(b[i+1]<<16)|(b[i+2]<<8)|b[i+3]; if(val===0x0fffffff) val=-1;}
        else             {w=8;val=-1;} // 5-8 byte VINTs treated as unknown
        if (i+w > n) return null;
        return {val, len:w};
    }
    let pos = 0;
    // Skip EBML header element (1A 45 DF A3)
    if (pos+4 > n || u32(pos) !== 0x1A45DFA3) return n;
    pos += 4;
    const es = vint(pos); if (!es || es.val < 0) return n;
    pos += es.len + es.val;
    // Segment element (18 53 80 67)
    if (pos+4 > n || u32(pos) !== 0x18538067) return n;
    pos += 4;
    const ss = vint(pos); if (!ss) return n;
    pos += ss.len; // enter Segment body
    // Walk top-level Segment elements — all use 4-byte IDs (start with 0x1x)
    while (pos+4 < n) {
        const eid = u32(pos);
        if (eid === 0x1F43B675) return pos; // Cluster
        pos += 4;
        const sz = vint(pos);
        if (!sz || sz.val < 0) return pos - 4; // unknown-size element = Cluster
        pos += sz.len + sz.val;
    }
    return n;
}

// -- MKV → WebM header patch ---------------------------------------------------
// MSE requires DocType="webm"; live recordings often carry DocType="matroska".
// The container structure is identical — only that 11-byte element differs.
// We replace:  42 82 88 "matroska"          (DocType, len=8, "matroska")
// with:        42 82 84 "webm" EC 82 00 00  (DocType, len=4, "webm" + 4-byte EBML Void)
// Total bytes: 11 → 11, so no offsets elsewhere in the file change.
function hexDump(buf, n) {
    const b = new Uint8Array(buf instanceof ArrayBuffer ? buf : buf.buffer, buf.byteOffset || 0, Math.min(n, buf.byteLength || buf.length));
    return Array.from(b).map(x => x.toString(16).padStart(2,'0')).join(' ');
}

function patchMkvToWebm(buf) {
    const src = buf instanceof ArrayBuffer ? buf : buf.buffer.slice(buf.byteOffset, buf.byteOffset + buf.byteLength);
    const b = new Uint8Array(src);
    const hexStr = hexDump(b, 16);
    console.log('init[0..15]: ' + hexStr);
    status('init[0..15]: ' + hexStr);
    for (let i = 0; i < Math.min(b.length - 11, 128); i++) {
        if (b[i] === 0x42 && b[i+1] === 0x82 && b[i+2] === 0x88 &&
            b[i+3] === 0x6D && b[i+4] === 0x61 && b[i+5] === 0x74 &&   // "mat"
            b[i+6] === 0x72 && b[i+7] === 0x6F && b[i+8] === 0x73 &&   // "ros"
            b[i+9] === 0x6B && b[i+10] === 0x61) {                      // "ka"
            const p = new Uint8Array(src.slice(0));
            p[i+2] = 0x84;                          // DocType length = 4
            p[i+3] = 0x77; p[i+4] = 0x65;          // "we"
            p[i+5] = 0x62; p[i+6] = 0x6D;          // "bm"
            p[i+7] = 0xEC;                          // EBML Void element ID
            p[i+8] = 0x82;                          // Void size VINT = 2
            p[i+9] = 0x00; p[i+10] = 0x00;         // Void payload
            console.log('patched matroska→webm at byte ' + i);
            status('patched matroska→webm at byte ' + i);
            return p.buffer;
        }
    }
    console.log('no matroska DocType found — passing through as-is');
    status('no matroska DocType found — passing through as-is');
    return src;
}

// -- SourceBuffer append queue -------------------------------------------------
// appendBuffer is async; only one call may be in flight at a time.
function sbEnqueue(data) {
    sbQueue.push(data);
    sbDrain();
}

function sbDrain() {
    if (!sb || sb.updating || !sbQueue.length) return;
    try {
        sb.appendBuffer(sbQueue[0]);
        sbQueue.shift();
    } catch(e) {
        if (e.name === 'QuotaExceededError' && video.currentTime > 15) {
            // Evict everything more than 10 s behind the playhead; retry on updateend.
            sb.remove(0, video.currentTime - 10);
        } else {
            sbQueue.shift(); // drop on unexpected errors
        }
    }
}

// -- Playback (MSE streaming) --------------------------------------------------
// Each seek creates a fresh MediaSource + SourceBuffer. The init segment is
// fetched once as a small range request; then a streaming fetch loop delivers
// data chunks directly into the SourceBuffer with no intermediate blobs.
// When the server closes the connection (its range-response cap) the loop
// immediately re-fetches from the current byte offset — the browser never
// sees a gap in the buffer.
async function playFromCue(cueIdx) {
    if (!videoBase || cues.length < 2) return;

    if (streamCtrl) { streamCtrl.abort(); streamCtrl = null; }

    liveBtn.classList.toggle('on', liveMode);
    scrub.value = cueIdx;
    const targetSec = cues[cueIdx].t / 1000;
    playPos.textContent = `${targetSec.toFixed(0)}s`;

    const initEnd  = cues[1].o;  // cues[0].o is always 0 (file start); cues[1].o is first cluster
    const lookback = liveMode ? 2 : 1;
    const startOff = cues[Math.max(0, cueIdx - lookback)].o;

    console.log(`playFromCue ${cueIdx} initEnd=${initEnd} startOff=${startOff} mime="${mime}" MSE=${!!window.MediaSource}`);
    status(`loading from ${targetSec.toFixed(1)}s...`);

    if (!window.MediaSource) {
        console.log('MediaSource not available on this browser');
        status('MediaSource not supported');
        return;
    }

    const thisMsRef = new MediaSource();
    ms = thisMsRef;
    sb = null;
    sbQueue = [];

    const prevSrc = video.src;
    video.src = URL.createObjectURL(thisMsRef);
    // Revoke the *previous* blob URL only; the new one must stay alive until
    // the browser resolves it (sourceopen), otherwise code=4 fires immediately.
    if (prevSrc && prevSrc.startsWith('blob:')) URL.revokeObjectURL(prevSrc);

    thisMsRef.addEventListener('sourceopen', async () => {
        if (ms !== thisMsRef) { status('MSE: superseded'); return; }

        let mimeType = (mime || 'video/webm').replace('video/x-matroska', 'video/webm');
        const supported = MediaSource.isTypeSupported(mimeType);
        console.log(`MSE open | mime="${mimeType}" supported=${supported} initEnd=${initEnd}`);
        status(`MSE open | mime="${mimeType}" supported=${supported} initEnd=${initEnd}`);
        if (!supported) mimeType = 'video/webm';

        try {
            sb = thisMsRef.addSourceBuffer(mimeType);
        } catch(e) {
            status('addSourceBuffer failed: ' + e.message);
            return;
        }
        sb.addEventListener('updateend', sbDrain);
        try { thisMsRef.duration = cues[cues.length - 1].t / 1000; } catch(e) {}

        const ctrl = new AbortController();
        streamCtrl = ctrl;
        const sig  = ctrl.signal;

        status(`fetching init bytes=0-${initEnd - 1}`);
        try {
            const r = await fetch(videoBase, {
                headers: { Range: `bytes=0-${initEnd - 1}` },
                signal: sig,
            });
            if (!r.ok || sig.aborted) { status(`init fetch failed: ${r.status}`); return; }
            const initBuf = await r.arrayBuffer();
            // Strip cluster data — MSE init segment must be headers-only.
            const clusterOff = findFirstCluster(initBuf);
            const initOnly = initBuf.slice(0, clusterOff);
            // Ensure streaming starts at a cluster boundary, not inside headers.
            if (startOff < clusterOff) startOff = clusterOff;
            console.log(`init ${initOnly.byteLength}b (cluster at ${clusterOff}), streaming from ${startOff}`);
            status(`init ${initOnly.byteLength}b (cluster@${clusterOff}), streaming from ${startOff}`);
            sbEnqueue(patchMkvToWebm(initOnly));
        } catch(e) { status('init fetch error: ' + e.message); return; }

        // Once the browser has parsed the codec metadata, seek and play.
        video.addEventListener('loadedmetadata', () => {
            if (ms !== thisMsRef) return;
            status(`loadedmetadata, seeking to ${targetSec.toFixed(1)}s`);
            video.currentTime = targetSec;
            video.play().catch(e => status('play() error: ' + e.message));
        }, { once: true });

        // Stream data chunks directly into the SourceBuffer.
        await streamData(thisMsRef, startOff, sig);
    }, { once: true });

    video.addEventListener('error', () => {
        const e = video.error;
        const msg = 'video error code=' + (e && e.code) + ' ' + (e && e.message);
        console.log(msg);
        status(msg);
    }, { once: true });
}

async function streamData(thisMsRef, off, sig) {
    // Cue offsets are MediaRecorder chunk boundaries, not Cluster boundaries.
    // Scan the first bytes we receive for the Cluster element ID (1F 43 B6 75)
    // and discard everything before it so MSE never sees a partial Cluster.
    let synced = false;

    while (!sig.aborted && ms === thisMsRef) {
        if (thisMsRef.readyState !== 'open') break;

        let r;
        try {
            r = await fetch(videoBase, {
                headers: { Range: `bytes=${off}-${off + 0x3FFFFFF}` },
                signal: sig,
            });
        } catch(e) { break; }
        if (!r.ok || sig.aborted) break;

        const reader = r.body.getReader();
        while (true) {
            let chunk;
            try { chunk = await reader.read(); } catch(e) { break; }
            if (chunk.done || sig.aborted) break;
            off += chunk.value.byteLength;

            let data = chunk.value;
            if (!synced) {
                // Find first Cluster ID in this chunk
                let cp = -1;
                for (let i = 0; i < data.length - 3; i++) {
                    if (data[i]===0x1F && data[i+1]===0x43 && data[i+2]===0xB6 && data[i+3]===0x75) {
                        cp = i; break;
                    }
                }
                if (cp < 0) continue; // no cluster yet — discard and keep reading
                console.log(`synced cluster at stream byte ${off - data.length + cp}`);
                data = data.slice(cp);
                synced = true;
            }
            sbEnqueue(data.slice());
        }

        if (sig.aborted) break;

        // Server closed the connection. If we haven't reached the last known
        // keyframe yet, re-fetch immediately. Otherwise wait for new cues.
        const lastKnownOff = cues.length ? cues[cues.length - 1].o : 0;
        if (off <= lastKnownOff) continue;
        await new Promise(resolve => setTimeout(resolve, 2000));
    }
}
</script>
</body></html>