Simple frame encoder

[tbrucet]

Hello, I was trying to write a simple encoder, that encodes single frames into a webm video. Writing the header and trailer works fine, but I am currently stuck at sending frames to the encoder. When calling encoder.send_frame or encoder.send_eof() I get an ffmpeg::Error(22: Invalid argument). I assume there is something wrong with the encoder setup, but I have no clue where exactly.
Very grateful for any help on this

extern crate ffmpeg_next as ffmpeg;
use ffmpeg::{ffi, Rational, format, codec, Frame};

fn main() {
    let out_name = "test.webm";
    let width = 1280;
    let height = 720;
    let frame_rate = Rational::new(25, 1);

    let codec = codec::encoder::find(codec::Id::VP9).unwrap();
    let ctx = unsafe {
        codec::context::Context::wrap(
            ffi::avcodec_alloc_context3(codec.as_ptr()), None)
    };

    let mut encoder = ctx.encoder().video().unwrap();
    encoder.set_height(height);
    encoder.set_width(width);
    encoder.set_frame_rate(Some(frame_rate));
    encoder.set_time_base(frame_rate.invert());
    encoder.set_format(format::Pixel::YUV420P);

    let mut octx = ffmpeg_next::format::output(&out_name).unwrap();
    let mut ost = octx.add_stream(codec).unwrap();
    ost.set_parameters(&encoder);

    octx.write_header().unwrap();

    /*
    ...
    send frames to encoder and write to file
    ...

    let frame = unsafe {
        Frame::empty()
    };
    encoder.send_frame(&frame).unwrap();
    */

    encoder.send_eof().unwrap();
    octx.write_trailer().unwrap();
}

[amfaber]

Just bumping because I am faced with the exact same problem