ff-remux

Stream-copy remuxing for Rust: trim a clip and replace / extract / add an audio stream, all without re-encoding.

ff-remux is a safe, ergonomic Rust wrapper over FFmpeg's stream-copy remuxing (libavformat demux + mux, no libavcodec encoding). Errors are typed and carry human-readable context (RemuxError), so a failure reads as an actionable message rather than a raw FFmpeg return code.

It is an independent crate: use it on its own, or combine it with the other ff-* crates to build any media app or editing model. The ff-* crates are model-free primitives that impose no editing model; avio is one editing engine built on top of them.

Installation

[dependencies]
ff-remux = "0.18"

FFmpeg 7.x or 8.x development libraries must be installed on your system.

Trim (stream copy)

StreamCopyTrim copies the selected time range without re-encoding, so it is fast and lossless.

use ff_remux::StreamCopyTrim;
use std::time::Duration;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Copy the range [10s, 25s) from input.mp4 into clip.mp4 without re-encoding.
    let start = Duration::from_secs(10);
    let end = Duration::from_secs(25);

    // new(input, start, end, output)
    StreamCopyTrim::new("input.mp4", start, end, "clip.mp4").run()?;

    let length = end - start;
    println!("wrote clip.mp4 ({length:?})");
    Ok(())
}

Audio replace / extract / add

use ff_remux::{AudioReplacement, AudioExtractor, AudioAdder};

// Replace the audio track of a video with a new audio file.
AudioReplacement::new("video.mp4", "music.aac", "out.mp4").run()?;

// Extract the audio track to its own file.
AudioExtractor::new("video.mp4", "audio.aac").run()?;

// Add an audio track to a video that has none.
AudioAdder::new("silent.mp4", "voice.aac", "out.mp4").run()?;

Error Handling

RemuxError implements ff_format::MediaError, so err.is_recoverable() / err.is_fatal() work uniformly with the other ff-* crates.

MSRV

Rust 1.93.0 (edition 2024).

License

MIT OR Apache-2.0