Split transcode and ffmpeg into separate modules

packages/transcode/ffmpeg.test.ts

@@ -4,13 +4,9 @@ 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',
   });

packages/transcode/ffmpeg.ts

@@ -1,31 +1,33 @@
 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;
+  'c:v'?: string;
+  'preset'?: string;
+  'loglevel'?: string;
+  'crf'?: string;
+  'c:a'?: string;
+  'b:a'?: string;
+  'movflags'?: string;
+  'f'?: string;
+  [key: string]: string | undefined;
 };
 
-export function ffmpeg(input: BodyInit, flags: FFmpegFlags): ReadableStream<Uint8Array> {
-  const command = new Deno.Command('ffmpeg', {
-    args: [
-      ...Object.entries(flags).flatMap(([k, v]) => [`-${k}`, v]),
-      'pipe:1', // Output to stdout
-    ],
-    stdin: 'piped',
-    stdout: 'piped',
-  });
+export function ffmpeg(input: ReadableStream<Uint8Array>, flags: FFmpegFlags): ReadableStream<Uint8Array> {
+  const args = ['-i', 'pipe:0']; // Input from stdin
+
+  for (const [key, value] of Object.entries(flags)) {
+    if (typeof value === 'string') {
+      args.push(`-${key}`, value);
+    }
+  }
+
+  args.push('pipe:1'); // Output to stdout
 
   // Spawn the FFmpeg process
+  const command = new Deno.Command('ffmpeg', { args, stdin: 'piped', stdout: 'piped' });
   const child = command.spawn();
 
   // Pipe the input stream into FFmpeg stdin and ensure completion
-  new Response(input).body!.pipeTo(child.stdin);
+  input.pipeTo(child.stdin);
 
+  // Return the FFmpeg stdout stream
   return child.stdout;
 }

packages/transcode/transcode.ts

@@ -1,6 +1,7 @@
+import { ffmpeg } from './ffmpeg.ts';
+
 export function transcodeVideo(input: ReadableStream<Uint8Array>): ReadableStream<Uint8Array> {
-  const opts = {
-    'i': 'pipe:0', // Read input from stdin
+  return ffmpeg(input, {
     'c:v': 'libx264', // Convert to H.264
     'preset': 'veryfast', // Encoding speed
     'loglevel': 'fatal', // Suppress logs
@@ -9,22 +10,5 @@ export function transcodeVideo(input: ReadableStream<Uint8Array>): ReadableStrea
     'b:a': '128k', // Audio bitrate
     'movflags': 'frag_keyframe+empty_moov', // Ensures MP4 streaming compatibility
     'f': 'mp4', // Force MP4 format
-  };
-
-  const command = new Deno.Command('ffmpeg', {
-    args: [
-      ...Object.entries(opts).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
-  input.pipeTo(child.stdin);
-
-  return child.stdout;
 }