v0.1

Goals

• Make it possible to encode single frames

Design

// struct Frame
let frame = createFrame();

// struct Context
let encoder = createEncoder();

// struct Context
let packet = encoder.encode(frame);

v0.2

Goal

• feed custom data

Notes

• use dcv-color-primitives
• Add data to Frame

  • strategy 1

  • strategy 2 (seems better)

    let data = canvas.data_i444();
    
    // Frame::new(width: usize, height: usize, chroma_sampling: ChromaSampling)
    let mut f: Frame<u8> = Frame::new(450, 450, ChromaSampling::Cs444);
    
    // Plane.copy_from_raw_u8(&mut self, source: &[u8], source_stride: usize, source_bytewidth: usize)
    f.planes[0].copy_from_raw_u8(data[0].as_slice(), 450, 1);
    f.planes[1].copy_from_raw_u8(data[1].as_slice(), 450 / 2, 1);
    f.planes[2].copy_from_raw_u8(data[2].as_slice(), 450 / 2, 1);
    

    • panics with:

      panicked at 'assertion failed: cfg.xorigin as isize + rect.x + rect.width as isize <= cfg.stride as isize', /home/urhengulas/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/src/libstd/macros.rs:13:23

      (from https://github.com/xiph/rav1e/blob/master/src/tiling/plane_region.rs#L153)

      • rect is probably rav1e::tiling::plane_region::Rect
      • something with tiling

  • next tries

    • get callstack for the panics → see where the panic is called
    • maybe good example: github.com/xiph/rav1e/tree/master/src/bin/decoder/y4m.rs

Next steps

• own input data (uploaded file, video from laptop camera)
  • 08:07:03 <@lu_zero> Urhengulas: I mean that your input will come from a MediaStreamTrack (or a canvas) 08:08:28 <@lu_zero> and we'll have to figure out how rav1e could fit, given MediaRecorder seems not a perfect fit
  • https://developer.mozilla.org/en-US/docs/Web/API/MediaRecorder#Example
• configure encoder
• error handling in js
• improve data transfer
  • maybe only copy data around on-demand

Research

JS Media Encoders

• fluent-ffmpeg

  This library abstracts the complex command-line usage of ffmpeg into a fluent, easy to use node.js module.

  • very nice API
  • example code