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();

// 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:

use ffmpeg_dev::sys::{
    AVMediaType_AVMEDIA_TYPE_VIDEO as AVMEDIA_TYPE_VIDEO,
    AVMediaType_AVMEDIA_TYPE_AUDIO as AVMEDIA_TYPE_AUDIO,
};
let ifmt_ctx: AVFormatContext = *ifmt_ctx;
let nb_streams = (*ifmt_ctx).nb_streams as usize;

// Extract video/audio/etc. streams from our mp4 file.
let streams = std::slice::from_raw_parts((*ifmt_ctx).streams, nb_streams)
    .iter()
    .map(|x| (*x).as_ref().expect("not null"))
    .collect::<Vec<&AVStream>>();

for (index, stream_ptr) in streams.iter().enumerate() {
    let codecpar = *stream_ptr.codecpar;
    if codecpar.codec_type == AVMEDIA_TYPE_AUDIO {
        println!("found audio stream at index {}", index);
    } else if codecpar.codec_type == AVMEDIA_TYPE_VIDEO {
        println!("found video stream at index {}", index);
    }
}

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.

Examples

$ cargo run --example h264_video_dec

Added as of this writing

• ./examples/remux.rs
• ./examples/h264_video_dec.rs

Miscellaneous

RLS - Editor/IDE Issues

For some reason (as of this writing) RLS has issues with multiple versions of ffmpeg-dev downloaded (under target). If there’s something I can fix on my side I’m happy to implement such changes. For now I’m just resorting my deleting the cache folder whenever I update ffmpeg-dev.

Miscellaneous Links:

• FFmpeg docs overview
• FFmpeg C API documentation
• FFmpeg C Examples (pretty easy to convert to rust in my experience)
• Rust docs

Sample or Test Content

• sintel_trailer-1080p.mp4
• ./assets/test/test.h264 - heavily compressed version of the video stream from sintel_trailer-1080p.mp4. This is a raw H264 encoded video binary.

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