main.rs

// ^^^ ffmpeg::init() is called in an other function

let mut context = ffmpeg::format::input(&path)?;
let duration;
let mut video;
let stream_index;

for stream in context.streams() {
    println!("Stream #{}", stream.index());
    println!("  Duration: {}", stream.duration());
    println!("  Frames: {}", stream.frames());
}

{
    let stream = context.streams().best(ffmpeg::media::Type::Video).unwrap();
    stream_index = stream.index();
    duration = stream.duration();
    println!("Frames: {}", stream.frames());
    video = stream.codec().decoder().video().unwrap();
}

let tmp_dir = TempDir::new("sidekick_thumbnails")?;

let args = format!("width={}:height={}:pix_fmt={}:time_base={}:sar={}",
                   video.width(),
                   video.height(),
                   "yuv420p",
                   video.time_base(),
                   video.aspect_ratio());

let mut filter = filter::Graph::new();
filter.add(&filter::find("buffer").unwrap(), "in", &args);
filter.add(&filter::find("buffersink").unwrap(), "out", "");

filter.output("in", 0)?
    .input("out", 0)?
    .parse("thumbnail=100");

filter.validate()?;

let mut decoded = ffmpeg::frame::Video::empty();

for i in 0..number {
    let offset = (((duration as f64)*((i as f64)+0.5))/(number as f64)) as i64;
    context.seek(offset, ..offset);
    println!("Seeking to {}", offset);

    let mut packets = 0;
    for (stream, mut packet) in context.packets() {
        if stream.index() == stream_index {
            packets += 1;
            println!("{}: {}", stream.index(), packets);
            if let Ok(_) = video.decode(&packet, &mut decoded) {
                println!("{}x{}", decoded.width(), decoded.height());
                filter.get("in").unwrap().source().add(&decoded);
            }
            if packets == 100 {
                break;
            }
        }
    }
}

filter.get("in").unwrap().source().flush();

let mut out = 0;
while let Ok(_) = filter.get("out").unwrap().sink().frame(&mut decoded) {
    println!("> {}", out);
    out += 1;

    let buf = image::ImageBuffer::<image::Rgb<u8>,&[u8]>::from_raw(decoded.width(), decoded.height(), decoded.data(0)).unwrap();
    buf.save(Path::new("/tmp/").join(format!("thumb{}.png", out))).unwrap();
}