fleabitdev

Experienced software developer, looking for freelance work or full-time employment.

    Location: UK
    Remote: Yes (or hybrid within the UK)
    Willing to relocate: No
    Resume/CV: By request
    Email: (my username) at protonmail dot com

Particularly good at cleaning up messes! Suitable freelance contracts might include legacy module rewrites, performance improvements, or the daunting new feature which nobody on your team wants to tackle.

I can be flexible on time zones. No interest in relocating long-term, but I'd be happy to visit your team in person for a few days to break the ice.

My specialist skills:

- The Rust language, which has been my daily driver for more than a decade.

- Multimedia (video, audio, image processing, 2D rendering...)

- Performance optimisation (SIMD, GPGPU, parallel programming...)

Fields in which I'm highly experienced, but below specialist level:

- Full-stack web development, with a frontend bias (TypeScript, React, WebGL, WebAssembly, AWS...)

- Native development, especially low-level Win32.

- Communication and technical writing, both learned in a previous career.

I also have a modest level of experience in computer vision, greenfield R&D, game engine development, programming language development, and data compression. I can offer a 50% discount for any contract which seems highly educational; my current areas of interest include DSP, embedded programming, robotics, functional languages, Swift, and React Native.

Thanks for reading, and I look forward to hearing from you :-)

Good catch - looks like it's a PNG image, with an alpha channel for the rounded corners, and a subtle gradient in the background. The gradient is rendered with dithering, to prevent colour banding. The dither pattern is random, which introduces lots of noise. Since noise can't be losslessly compressed, the PNG is an enormous 6.2 bits per pixel.

While working on a web-based graphics editor, I've noticed that users upload a lot of PNG assets with this problem. I've never tracked down the cause... is there a popular raster image editor which recently switched to dithered rendering of gradients?

As I understand it, very small neural networks have already been incorporated into both VVC and AV2 for intra prediction. You're correct that this strategy is limited by decoding performance, especially when predicting large blocks.

In general, I'm pessimistic about prediction-and-residuals strategies for lossy compression. They tend to amplify noise; they create data dependencies, which interfere with parallel decoding; they require non-local optimisation in the encoder; really good prediction involves expensive analysis of a large number of decoded pixels; and it all feels theoretically unsound (because predictors usually produce just one value, rather than a probability distribution).

I'm more optimistic about lossy image codecs based on explicitly-coded summary statistics, with very little prediction. That approach worked well for lossy JPEG XL.

JPEG XL achieves about half the bitrate of an equal-quality JPEG, even at lower quality levels. That's a real achievement, but the complexity cost is high; I'd estimate that JPEG XL decoders are at least ten times more complex than JPEG decoders. Modern lossy image codecs are "JPEG, with three decades of patch notes" :-)

I think we're badly in need of an entirely new image compression technique; the block-based DCT has serious flaws, such as its high coding cost for edges and its tendency to create block artefacts. The modern hardware landscape is quite different from 1992, so it's plausible that the original researchers might have missed something important, all those years ago.

I only recently learned that JPEG and MPEG-1 were designed for near-lossless compression, so the massive bitrate reductions which came further down the road had nothing to do with the original design.

"Inelegant" is the right word; it's hard to shake off the feeling that we might have missed something important. I suspect the next big breakthrough might be waiting for researchers to focus on lower-quality compression specifically, rather than requiring every new codec to improve the state of the art in near-lossless compression.