FFmpeg.js

A better ffmpeg.wasm front end, allowing for it to be included in a single line of js, and is independent of the ffmpeg-core version.

See the demo page here

FFmpeg Async Command API

This documentation describes the available asynchronous functions for interacting with an in-memory FFmpeg filesystem.

Usage

All functions are asynchronous and should be called using await.

let dirs = await ffmpeg.listDir(".");

Usage

listDir(path)

Lists the contents of a directory.

• Parameters:

  • path (string): The directory path to list.

• Returns: string[] - An array of filenames in the directory.

• Example:

  let dirs = await ffmpeg.listDir(".");
  console.log(dirs);

mkdir(path)

Creates a new directory.

• Parameters:

  • path (string): The directory path to create.

• Returns: string - The created directory path.

• Example:

  await ffmpeg.mkdir("/new-folder");

readFileToUrl(path)

Reads a file and returns a blob URL.

• Parameters:

  • path (string): The file path to read.

• Returns: string - A blob URL representing the file contents.

• Example:

  let fileUrl = await ffmpeg.readFileToUrl("video.mp4");
  console.log(fileUrl);

rename(oldname, newname)

Renames a file or directory.

• Parameters:

  • oldname (string): The current file/directory name.
  • newname (string): The new name.

• Returns: string - The new name.

• Example:

  await ffmpeg.rename("old.mp4", "new.mp4");

writeFileFromUrl(path, url)

Writes a file from a given URL to the FFmpeg filesystem.

• Parameters:

  • path (string): The target file path.
  • url (string): The source URL of the file.

• Returns: string - The written file path.

• Example:

  await ffmpeg.writeFileFromUrl("video.mp4", "https://example.com/video.mp4");

exec(args)

Executes an FFmpeg command.

• Parameters:

  • args (string[]): An array of command-line arguments for FFmpeg.

• Returns: The execution result.

• Example:

  let result = await ffmpeg.exec(["-i", "input.mp4", "-vf", "scale=1280:720", "output.mp4"]);
  console.log(result);

writeFile(path, data)

Writes data to a file in the FFmpeg filesystem.

• Parameters:
  • path (string): The target file path.
  • data (Uint8Array | string): The data to write.
• Returns: string - The written file path.
• Example:

  let data = new Uint8Array([0x00, 0x01, 0x02]);
  await ffmpeg.writeFile("file.bin", data);

readFile(path, isString)

Reads a file from the FFmpeg filesystem.

• Parameters:
  • path (string): The file path to read.
  • isString (boolean): Whether to decode the file as a string.
• Returns: Uint8Array | string - The file contents.
• Example:

  let binaryData = await ffmpeg.readFile("file.bin");
  let textData = await ffmpeg.readFile("file.txt", true);

setLogger(func)

Sets the logging function.

• Parameters:
  • func (function): A function that receives log messages.
• Example:

  ffmpeg.setLogger(console.log);

setProgress(func)

Sets the progress tracking function.

• Parameters:
  • func (function): A function that receives progress updates.
• Example:

  ffmpeg.setProgress(progress => console.log("Progress:", progress));