FFmpeg Sidecar 🏍

Wrap a standalone FFmpeg binary in an intuitive Iterator interface.

Motivation

The core goal of this project is to provide a method of interacting with any video as if it were an array of raw RGB frames.

Of course, that's what video is, fundamentally, but there is a whole pandora's box of complexity in terms of receiving and decoding video before you get there.

Using FFmpeg as the core engine provides interoperability between a massive range of formats, containers, extensions, protocols, encoders, decoders, hardware accelerations, and more.

Why CLI?

One method of using FFmpeg is low-level bindings to the code used inside the CLI itself -- there are good crates in the Rust ecosystem that do this.

Low level bindings have drawbacks, though:

Difficult, time-consuming build, toolchain, and dependencies, especially on Windows
Complexity, especially for beginners
You end up manually re-implementing a lot of the standard conversions you need from scratch

By wrapping the CLI, this crate avoids those downsides, and also solves some of the pain points that you would encounter if you were to use the CLI directly on its own:

Raw data can easily move in and out of FFmpeg instances, or piped between them. Under the hood they are moving across stdin and stdout.
Rich semantic information is recovered from the ffmpeg stderr logs, including:
- Progress updates (frame #, timestamp, speed, bitrate, ...)
- Input/output metadata and stream mappings
- Warnings & errors
Argument presets and aliases with discoverable names through Intellisense/autocomplete

The only remaining downside is the size of the FFmpeg binary itself, but it's less than 100MB when zipped.

Getting started

1. Download FFmpeg

First you need an FFmpeg binary. If you don't already have one, head to https://ffmpeg.org. Either install it globally (e.g. add to PATH on windows), or simply place the executable adjacent to your Rust binary target. When you package and distribute

2. Cargo install

On the Rust side, it has zero Cargo dependencies! 🎉

cargo add ffmpeg-sidecar

Examples

Hello world 👋

Read raw video frames.

use ffmpeg_sidecar::{
  child::FfmpegChild, command::FfmpegCommand, event::FfmpegEvent, iter::FfmpegIterator,
};

/// Iterates over the frames of a testsrc.
fn main() {
  // similar to `std::process::Command`
  let mut command = FfmpegCommand::new();
  command
    .testsrc() // generate a test pattern video
    .rawvideo(); // pipe raw video output

  // similar to `std::process::Child`
  let mut child: FfmpegChild = command.spawn().unwrap();

  // Iterator over all messages and output
  let iter: FfmpegIterator = child.iter().unwrap();
  iter.for_each(|event: FfmpegEvent| {
    match event {
      FfmpegEvent::OutputFrame(frame) => {
        let _pixels = frame.data; // <- raw RGB pixels! 🎨
      }
      FfmpegEvent::Error(e) => eprintln!("Error: {}", e),
      _ => {}
    }
  });
}

Source: /examples/hello_world.rs

cargo run --example hello-world

H265 Transcoding

Decode H265, modify the decoded frames, and then write back to H265.

Source: /examples/h265_transcode.rs

cargo run --example h265_transcode

FFplay

Pipe an FFmpeg instance to FFplay for debugging purposes.

Source: /examples/ffplay_preview.rs

cargo run --example ffplay_preview

Others

For a myriad of other examples, check any of the unit tests in /src/test.rs in this repo.

Todo

Add /examples
Take input from stdin, and pipe between iterators
Pipe directly to ffplay for debugging
Idiomatic error type instead of Result<_, String>
Handle indeterminate output formats like H264/H265
- Currently these formats are mutually exclusive with using iter() since they require consuming stdout directly