Files
argument.es/scripts/stream-browser.ts
Theo Browne 4d56f95f9f bug fixes
2026-02-22 16:40:30 -08:00

336 lines
8.7 KiB
TypeScript

import puppeteer from "puppeteer";
type Mode = "live" | "dryrun";
type SinkWriter = {
write(chunk: Uint8Array): number;
end(error?: Error): number;
};
function parsePositiveInt(value: string | undefined, fallback: number): number {
const parsed = Number.parseInt(value ?? "", 10);
return Number.isFinite(parsed) && parsed > 0 ? parsed : fallback;
}
function usage(): never {
console.error("Usage: bun scripts/stream-browser.ts <live|dryrun>");
console.error("Required for live mode: TWITCH_STREAM_KEY");
process.exit(1);
}
function resolveMode(value: string | undefined): Mode {
if (value === "live" || value === "dryrun") return value;
return usage();
}
const mode = resolveMode(process.argv[2]);
const streamFps = parsePositiveInt(process.env.STREAM_FPS, 30);
const captureBitrate = parsePositiveInt(process.env.STREAM_CAPTURE_BITRATE, 12_000_000);
const targetSize = process.env.STREAM_TARGET_SIZE ?? "1920x1080";
const targetParts = targetSize.split("x");
const targetWidth = targetParts[0] ?? "1920";
const targetHeight = targetParts[1] ?? "1080";
const videoBitrate = process.env.STREAM_VIDEO_BITRATE ?? "6000k";
const maxrate = process.env.STREAM_MAXRATE ?? "6000k";
const bufsize = process.env.STREAM_BUFSIZE ?? "12000k";
const gop = String(parsePositiveInt(process.env.STREAM_GOP, 60));
const audioBitrate = process.env.STREAM_AUDIO_BITRATE ?? "160k";
const streamKey = process.env.TWITCH_STREAM_KEY;
const serverPort = process.env.STREAM_APP_PORT ?? "5109";
const broadcastUrl = process.env.BROADCAST_URL ?? `http://127.0.0.1:${serverPort}/broadcast`;
if (mode === "live" && !streamKey) {
console.error("TWITCH_STREAM_KEY is not set.");
process.exit(1);
}
async function assertBroadcastReachable(url: string) {
const timeoutMs = 5_000;
const controller = new AbortController();
const timeout = setTimeout(() => controller.abort(), timeoutMs);
try {
const res = await fetch(url, { signal: controller.signal });
if (!res.ok) {
throw new Error(`HTTP ${res.status}`);
}
} catch (error) {
const detail = error instanceof Error ? error.message : String(error);
throw new Error(
`Cannot reach broadcast page at ${url} (${detail}). Start the app server first (bun run start or bun run start:web).`,
);
} finally {
clearTimeout(timeout);
}
}
function buildFfmpegArgs(currentMode: Mode): string[] {
const args = [
"-hide_banner",
"-loglevel",
"warning",
"-fflags",
"+genpts",
"-f",
"webm",
"-i",
"pipe:0",
"-f",
"lavfi",
"-i",
"anullsrc=channel_layout=stereo:sample_rate=44100",
"-map",
"0:v:0",
"-map",
"1:a:0",
"-vf",
`scale=${targetWidth}:${targetHeight}:force_original_aspect_ratio=decrease,pad=${targetWidth}:${targetHeight}:(ow-iw)/2:(oh-ih)/2`,
"-c:v",
"libx264",
"-preset",
"veryfast",
"-tune",
"zerolatency",
"-pix_fmt",
"yuv420p",
"-b:v",
videoBitrate,
"-maxrate",
maxrate,
"-bufsize",
bufsize,
"-g",
gop,
"-keyint_min",
gop,
"-sc_threshold",
"0",
"-c:a",
"aac",
"-b:a",
audioBitrate,
"-ar",
"44100",
"-ac",
"2",
];
if (currentMode === "live") {
args.push("-f", "flv", `rtmp://live.twitch.tv/app/${streamKey}`);
return args;
}
args.push("-f", "mpegts", "pipe:1");
return args;
}
async function pipeReadableToSink(
readable: ReadableStream<Uint8Array>,
sink: SinkWriter,
) {
const reader = readable.getReader();
try {
while (true) {
const { done, value } = await reader.read();
if (done) break;
if (value) sink.write(value);
}
} finally {
sink.end();
}
}
async function main() {
await assertBroadcastReachable(broadcastUrl);
const ffmpegArgs = buildFfmpegArgs(mode);
const ffmpeg = Bun.spawn(["ffmpeg", ...ffmpegArgs], {
stdin: "pipe",
stdout: mode === "dryrun" ? "pipe" : "inherit",
stderr: "inherit",
});
let ffmpegWritable = true;
let ffplay: Bun.Subprocess | null = null;
let ffplayPump: Promise<void> | null = null;
if (mode === "dryrun") {
ffplay = Bun.spawn(
[
"ffplay",
"-hide_banner",
"-fflags",
"nobuffer",
"-flags",
"low_delay",
"-framedrop",
"-i",
"pipe:0",
],
{
stdin: "pipe",
stdout: "inherit",
stderr: "inherit",
},
);
const stdout = ffmpeg.stdout;
if (!stdout || !ffplay.stdin) {
throw new Error("Failed to pipe ffmpeg output into ffplay.");
}
if (typeof ffplay.stdin === "number") {
throw new Error("ffplay stdin is not writable.");
}
ffplayPump = pipeReadableToSink(stdout, ffplay.stdin as SinkWriter);
}
let firstChunkResolve: (() => void) | null = null;
let firstChunkReject: ((error: Error) => void) | null = null;
const firstChunk = new Promise<void>((resolve, reject) => {
firstChunkResolve = resolve;
firstChunkReject = reject;
});
let shutdown: (() => Promise<void>) | null = null;
const chunkServer = Bun.serve({
port: 0,
fetch(req, server) {
const url = new URL(req.url);
if (url.pathname === "/chunks" && server.upgrade(req)) {
return;
}
return new Response("Not found", { status: 404 });
},
websocket: {
message(_ws, message) {
if (!ffmpegWritable || !ffmpeg.stdin || typeof ffmpeg.stdin === "number") {
return;
}
if (typeof message === "string") return;
let chunk: Uint8Array | null = null;
if (message instanceof ArrayBuffer) {
chunk = new Uint8Array(message);
} else if (ArrayBuffer.isView(message)) {
chunk = new Uint8Array(
message.buffer,
message.byteOffset,
message.byteLength,
);
}
if (!chunk) return;
try {
ffmpeg.stdin.write(chunk);
firstChunkResolve?.();
firstChunkResolve = null;
firstChunkReject = null;
} catch (error) {
ffmpegWritable = false;
const detail = error instanceof Error ? error : new Error(String(error));
firstChunkReject?.(detail);
firstChunkResolve = null;
firstChunkReject = null;
void shutdown?.();
}
},
},
});
const browser = await puppeteer.launch({
headless: true,
args: [
"--autoplay-policy=no-user-gesture-required",
"--disable-background-timer-throttling",
"--disable-renderer-backgrounding",
"--disable-backgrounding-occluded-windows",
],
});
const page = await browser.newPage();
await page.setViewport({ width: 1920, height: 1080, deviceScaleFactor: 1 });
page.on("console", (msg) => {
if (process.env.STREAM_DEBUG === "1") {
console.log(`[broadcast] ${msg.type()}: ${msg.text()}`);
}
});
const captureUrl = new URL(broadcastUrl);
captureUrl.searchParams.set("sink", `ws://127.0.0.1:${chunkServer.port}/chunks`);
captureUrl.searchParams.set("captureFps", String(streamFps));
captureUrl.searchParams.set("captureBitrate", String(captureBitrate));
await page.goto(captureUrl.toString(), { waitUntil: "networkidle2" });
await page.waitForSelector("#broadcast-canvas", { timeout: 10_000 });
const firstChunkTimer = setTimeout(() => {
firstChunkReject?.(
new Error("No media chunks received from headless browser within 10s."),
);
}, 10_000);
await firstChunk.finally(() => clearTimeout(firstChunkTimer));
console.log(`Streaming from ${broadcastUrl} in ${mode} mode`);
let shuttingDown = false;
shutdown = async () => {
if (shuttingDown) return;
shuttingDown = true;
ffmpegWritable = false;
try {
chunkServer.stop(true);
} catch {}
try {
await browser.close();
} catch {}
try {
ffmpeg.stdin?.end();
} catch {}
try {
ffmpeg.kill();
} catch {}
if (ffplay) {
try {
if (ffplay.stdin && typeof ffplay.stdin !== "number") {
ffplay.stdin.end();
}
} catch {}
try {
ffplay.kill();
} catch {}
}
};
const ffmpegExit = ffmpeg.exited.then((code) => {
ffmpegWritable = false;
void shutdown?.();
return code;
});
process.on("SIGINT", () => {
void shutdown?.();
});
process.on("SIGTERM", () => {
void shutdown?.();
});
const exitCode = await ffmpegExit;
if (ffplayPump) {
await ffplayPump.catch(() => {
// Ignore downstream pipe failures on shutdown.
});
}
if (ffplay) {
await ffplay.exited;
}
await shutdown?.();
if (exitCode !== 0) {
process.exit(exitCode);
}
}
main().catch((error) => {
const detail = error instanceof Error ? error.message : String(error);
console.error(detail);
process.exit(1);
});