ffipeg_muxer

CLI and API to use FFmpeg FFI to mux separate audio and video files into a single output file.

Example Usage

void main() {
    // Use FFmpeg on macOS installed via Homebrew:
    final muxer = Muxer(DynamicLibrary.open('/opt/homebrew/bin/ffmpeg'));
    // Use FFmpeg in macOS Desktop Flutter app installed via `fvp` (v0.26.1) package:
    final muxer = Muxer(DynamicLibrary.open('libffmpeg.7.dylib'));
    final result = muxer.run(
        videoFile: '/path/to/video.webm',
        audioFile: '/path/to/audio.mp4',
        outputFile: '/path/to/output.mp4',
    );
    switch (result) {
        case MuxerOK(:final outputFile):
            print('Successfully muxed to $outputFile');
            break;
        case MuxerError(:final message):
            print('Muxing failed: $message');
            throw result;
    }
}

Installation

• Only this package and the ffmpeg binary are required, since bindings are already generated (ffipeg is a transitive dependency):

dart pub add ffipeg_muxer

Features

• This package only muxes; it does not transcode, retime, filter, or do anything else.
• Both files will be muxed from the beginning.
• If the video input is longer than the audio, the remaining video will be silent.
• If the audio input is longer than the video, the remaining audio will have black video.
• I've only tested this with VP9 video and Opus audio, but H.264 and AAC should work fine.
• The resulting files will likely not play back in QuickTime (as it does not support much!). Use VLC and ffprobe to test outputs.

Please refer to the ffipeg package README for more info / further usage of FFI bindings to FFmpeg in Dart.

Contributions

Contributions are welcome, especially if any bugs are found. Please open an issue in the repo at https://github.com/dra11y/ffipeg-dart.

Any new features in this package should be muxing-related. I'm open to transcoding if someone wants to undertake/contribute it (should perform well and bypass transcoding if not needed).