About

Direct, unobscured and self contained FFmpeg (sys) bindings.

By self contained I mean:

Does not require or link against any FFmpeg system dependencies.
Does not require a network connection for building.

The FFmpeg bindings now include doc comments, including struct fields! See here.

Example

let input_path_cstr = std::ffi::CString::new("path/to/source.mp4").unwrap("to c str");

// Open an e.g. MP4 file
avformat_open_input(
    &mut ifmt_ctx,
    input_path_cstr.as_ptr(),
    std::ptr::null_mut(),
    std::ptr::null_mut(),
);
avformat_find_stream_info(ifmt_ctx, std::ptr::null_mut());

// Print info about the loaded file
av_dump_format(
    ifmt_ctx,
    0,
    input_path_cstr.as_ptr(),
    0,
);

For the uninitiated, the std includes lots of convenient ffi related utilities. E.g. using std::slice::from_raw_parts:

let ifmt_ctx: AVFormatContext = *ifmt_ctx;

// Extract video/audio/etc. streams from our mp4 file
let streams: &[AVStream] = std::slice::from_raw_parts(
    *ifmt_ctx.streams, 
    ifmt_ctx.nb_streams as usize
);

// C bindings require zero for loops 😌 - instead turn C dynamic arrays into Rust array refs
for stream in std::slice::from_raw_parts(*ifmt_ctx.streams, ifmt_ctx.nb_streams as usize) {
    /// ... stream is of type '&AVStream'
}

Stability

API bindings should be practically stable now.

Internal Behavior

By default the debug or dev builds compile FFmpeg without optimizations, this is for the purpose of speeding up compilation. Compiling on release mode or setting opt-level > 1 will disable this behavior.

LICENSE WARNING

I’m not a lawyer, furthermore I really don’t understand software licenses.

This codebase is MIT.
At compile time, this library builds and statically links against LGPL code.
- This is for the purpose of being self contained, without burdening any library consumers with dependency issues.

Hopefully one day the rust ecosystem will get a decent FFmpeg alternative for e.g. container muxing/demuxing.

Future

It would be interesting to experiment with compiling FFmpeg to WebAssembly. Perhaps as an alternative to static linking, if a local version isn’t available it could link to a remote lib over the network.