ffmpeg4js v5.0.26

FFmpeg4JS

中文

Builds

Modern (Default)

Decoders

Encoders

Version scheme

FFmpeg4JS uses the following version pattern: major.minor.ddd, where:

• major - FFmpeg's major version number used in the builds.
• minor - FFmpeg's minor version.
• ddd - FFmpeg4JS patch version.

Current 5.0.25

Usage

Using FFmpeg4JS is very easy, but please note that this library is designed to run in the Worker (especially the Web Worker)
If you plan to use FFmpeg in NodeJS, please call the native ffmpeg directly, FFmpeg4JS may not work properly in NodeJS Worker

Sync

In general, we don't recommend synchronous calls,
as this will cause WASM to run in the main thread and the UI will definitely block while executing.
So here we do a very simple thing to verify that if our library is working properly

import FFmpeg4JS from "ffmpeg4js";

export async function FFInfo() {
  await FFmpeg4JS(undefined, {
    arguments: ["-codecs"],
  });

  console.debug("------------------");

  await FFmpeg4JS(undefined, {
    arguments: ["-hide_banner", "-formats"],
  });
}

Try calling FFInfo() and you should see a lot of output from FFmpeg in the console, otherwise you should check what's wrong

Async

Let's take a file converted to Opus as an example

import * as Comlink from "comlink";
import type FFmpeg4JS from "ffmpeg4js";

export async function ToOpus(
  name: string,
  data: ArrayBuffer
): Promise<Uint8Array | undefined> {
  const worker = new Worker(
    new URL("~/node_modules/ffmpeg4js/src/index", import.meta.url),
    { type: "module" }
  );

  const ff = Comlink.wrap<typeof FFmpeg4JS>(worker);
  const res = await ff(Comlink.transfer([{ name, data }], [data]), {
    arguments: [
      "-hide_banner",
      "-i",
      name,
      "-strict",
      "-2",
      "-c:a",
      "opus",
      `${name}.opus`,
    ],
  });

  worker.terminate();
  return res.find((x) => x.name === `${name}.opus`)?.data;
}

Tips

• Please give preference to WebCodecs before using FFmpeg

• The new URL should be determined according to your project environment
  UMI (Webpack) can be written directly as new Worker(new URL("ffmpeg4js", import.meta.url));

• We use Comlink to optimize the Worker workflow

• Comlink.transfer is not required, but it is better to do so.
  If data is an object such as Uint8Array that stores its contents in buffer
  Please write as Comlink.transfer([{ name, data }], [data.buffer])

• Don't forget to close the unused worker: worker.terminate(); otherwise the memory may not be freed

• Each FFmpegModule can only be used once
  But you can call FFmpeg4JS repeatedly, and each call will generate a new instance of FFmpegModule

• FFmpeg4JS does not escape ts and optimize js files (but does optimize WASM)
  make sure your environment can handle them

• In FFmpeg4JS, you cannot override stdout and stderr
  Because they have line break recognition problems, pass print and printErr instead

• If you are not satisfied with the default Wrapper, you can do it yourself
  import factory from "ffmpeg4js/src/ffmpeg";