Initial commit

.gitignore

@@ -0,0 +1,2 @@
+/node_modules/
+/lib/

package.json

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+{
+  "name": "record",
+  "version": "1.0.0",
+  "description": "",
+  "main": "lib/record.js",
+  "scripts": {
+    "start": "npm run build && node lib/record.js",
+    "build": "tsc"
+  },
+  "type": "module",
+  "author": "",
+  "license": "ISC",
+  "devDependencies": {
+    "ts-node": "^10.8.2",
+    "typescript": "^4.7.4",
+    "zx": "^7.0.7"
+  }
+}

record.ts

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+#!/usr/bin/env -S ts-node-esm --compilerOptions='{"module": "es2022"}'
+
+$.verbose = false;
+
+import { $ } from "zx";
+// Or
+import "zx/globals";
+import { spawn } from "child_process";
+import { PassThrough } from "stream";
+
+function sleep(time: number) {
+  return new Promise<void>((resolve) => {
+    setTimeout(() => resolve(), time);
+  });
+}
+
+void (async function () {
+  const source = spawn("ffmpeg", [
+    "-f",
+    "video4linux2",
+    "-input_format",
+    "nv12",
+    "-thread_queue_size",
+    "512",
+    "-video_size",
+    "3840x2160",
+    "-i",
+    "/dev/video2",
+    "-f",
+    "nut",
+    "-c",
+    "copy",
+    "pipe:1",
+  ]);
+  const preview = spawn("ffplay", [
+    "-f",
+    "nut",
+    "-use_wallclock_as_timestamps",
+    "1",
+    "-",
+  ]);
+  const convert_and_add_audio = spawn("ffmpeg", [
+    "-y",
+    "-vaapi_device",
+    "/dev/dri/renderD128",
+    "-f",
+    "nut",
+    "-i",
+    "-",
+    "-f",
+    "pulse",
+    "-thread_queue_size",
+    "512",
+    "-i",
+    "alsa_input.usb-Elgato_Cam_Link_4K_0123456789000-03.analog-stereo",
+    "-vf",
+    "format=nv12,hwupload",
+    "-c:v",
+    "h264_vaapi",
+    "-b:v",
+    "12M",
+    "-f",
+    "mp4",
+    "output.mp4",
+  ]);
+  console.log("started ffmpeg...");
+
+  source.stderr.on("data", (data) => {
+    // console.error("source", data.toString());
+  });
+  convert_and_add_audio.stderr.on("data", (data) => {
+    // console.error("convert", data.toString());
+  });
+  preview.stderr.on("data", (data) => {
+    // console.error("preview", data.toString());
+  });
+
+  // preview.stderr.on("data", (data) => console.error(data.toString()));
+
+  const source_stream_for_convert = new PassThrough();
+  const source_stream_for_preview = new PassThrough();
+  // const source_stream_for_dump = new PassThrough();
+
+  // source.stdout.pipe(source_stream_for_convert);
+  // // source.stdout.pipe(source_stream_for_preview);
+  // source.stdout.pipe(source_stream_for_dump);
+  //
+  source_stream_for_convert.pipe(convert_and_add_audio.stdin);
+  // source_stream_for_preview.pipe(preview.stdin);
+
+  let preview_ok = true;
+  const stats = {};
+  let count = 0;
+  let preview_stopped = false;
+  let preview_can_resume = false;
+  let preview_should_stop_asap = false;
+  source.stdout.on("data", (data) => {
+    // this implements framedropping. we detect when a frame starts and emit it only when the stdin is drained
+    count++;
+    // console.log("got data!", a++);
+    const beginning = data.slice(0, 4).join("");
+    if (beginning == "7875228173") {
+      //means the beginning of the frame (counted the most frequent start of data and that was the most frequent)
+      if (preview_can_resume) {
+        preview_stopped = false;
+      }
+      if (preview_should_stop_asap) {
+        preview_should_stop_asap = false;
+        preview_stopped = true;
+      }
+    }
+
+    if (!preview_stopped) {
+      let preview_result = preview.stdin.write(data);
+      if (!preview_result && !preview_should_stop_asap) {
+        preview_should_stop_asap = true;
+        preview_can_resume = false;
+        preview.stdin.once("drain", () => {
+          preview_can_resume = true;
+        });
+      }
+    }
+    convert_and_add_audio.stdin.write(data);
+  });
+})();

tsconfig.json

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+{
+  "compilerOptions": {
+    "module": "ESNext",
+    "moduleResolution": "nodenext",
+    "esModuleInterop": true,
+    "noImplicitAny": true,
+    "noImplicitThis": true,
+    "strictNullChecks": true,
+    "outDir": "./lib"
+  },
+  "files": ["record.ts"],
+  "exclude": ["node_modules/**/*"]
+}