Add ffmpeg module

packages/transcode/ffmpeg.test.ts

@@ -0,0 +1,20 @@
+import { ffmpeg } from './ffmpeg.ts';
+
+Deno.test('ffmpeg', async () => {
+  await using file = await Deno.open(new URL('./buckbunny.mp4', import.meta.url));
+
+  const output = ffmpeg(file.readable, {
+    'i': 'pipe:0',
+    'c:v': 'libx264',
+    'preset': 'veryfast',
+    'loglevel': 'fatal',
+    'crf': '23',
+    'c:a': 'aac',
+    'b:a': '128k',
+    'movflags': 'frag_keyframe+empty_moov',
+    'f': 'mp4',
+  });
+
+  await Deno.mkdir(new URL('./tmp', import.meta.url), { recursive: true });
+  await Deno.writeFile(new URL('./tmp/buckbunny-transcoded.mp4', import.meta.url), output);
+});

packages/transcode/ffmpeg.ts

@@ -0,0 +1,31 @@
+export type FFmpegFlags = {
+  'i': string;
+  'c:v': string;
+  'preset': string;
+  'loglevel': string;
+  'crf': string;
+  'c:a': string;
+  'b:a': string;
+  'movflags': string;
+  'f': string;
+  [key: string]: string;
+};
+
+export function ffmpeg(input: BodyInit, flags: FFmpegFlags): ReadableStream<Uint8Array> {
+  const command = new Deno.Command('ffmpeg', {
+    args: [
+      ...Object.entries(flags).flatMap(([k, v]) => [`-${k}`, v]),
+      'pipe:1', // Output to stdout
+    ],
+    stdin: 'piped',
+    stdout: 'piped',
+  });
+
+  // Spawn the FFmpeg process
+  const child = command.spawn();
+
+  // Pipe the input stream into FFmpeg stdin and ensure completion
+  new Response(input).body!.pipeTo(child.stdin);
+
+  return child.stdout;
+}