web: barebones core for ffmpeg & remux page

web/src/lib/ffmpeg.ts

@@ -0,0 +1,63 @@
+import ffmpegCore from "@imput/ffmpeg-core?url";
+import ffmpegCoreWASM from "@imput/ffmpeg-core/wasm?url";
+
+import { FFmpeg } from "@imput/ffmpeg.wasm";
+import { fetchFile } from "@imput/ffmpeg-util";
+
+export default class FFmpegWrapper {
+    initialized: boolean;
+    ffmpeg: FFmpeg;
+    concurrency: number;
+
+    constructor() {
+        this.ffmpeg = new FFmpeg();
+        this.initialized = false;
+
+        this.concurrency = Math.min(4, navigator.hardwareConcurrency);
+    }
+
+    async init() {
+        if (this.initialized) {
+            this.ffmpeg.terminate();
+        } else {
+            this.initialized = true;
+            this.ffmpeg.on("log", ({ message }) => {
+                console.log(message);
+            });
+        }
+
+        await this.ffmpeg.load({
+            coreURL: ffmpegCore,
+            wasmURL: ffmpegCoreWASM,
+            workerURL: "/ffmpeg-core.worker.js",
+        });
+    }
+
+    terminate() {
+        this.initialized = false;
+        return this.ffmpeg.terminate();
+    }
+
+    async renderFile(url: string, type: string, format: string) {
+        const input = `input.${format}`;
+
+        await this.ffmpeg.writeFile(
+            input,
+            await fetchFile(url)
+        )
+
+        await this.ffmpeg.exec([
+            '-threads', this.concurrency.toString(),
+            '-i', input,
+            '-c', 'copy',
+            `output.${format}`
+        ]);
+
+        const data = await this.ffmpeg.readFile(`output.${format}`);
+        const finalBlob = URL.createObjectURL(
+            new Blob([data], { type: `${type}/${format}` })
+        );
+
+        return finalBlob
+    }
+}