libjpeg-turbo VS matrix.to

> all decoders will render the same pixels

Not true. Even just within libjpeg, there are three different IDCT implementations (jidctflt.c, jidctfst.c, jidctint.c) and they produce different pixels (it's a classic speed vs quality trade-off). It's spec-compliant to choose any of those.

A few years ago, in libjpeg-turbo, they changed the smoothing kernel used for decoding (incomplete) progressive JPEGs, from a 3x3 window to 5x5. This meant the decoder produced different pixels, but again, that's still valid:

https://github.com/libjpeg-turbo/libjpeg-turbo/commit/6d91e9...

Last vestiges of this fact AFAIK were libjpeg, which had a macro NEED_SHORT_EXTERNAL_NAMES that shortens all public identifiers to have unique 6-letter-long prefixes. Libjpeg-turbo nowadays has removed them though [1].

[1] https://github.com/libjpeg-turbo/libjpeg-turbo/commit/52ded8...

While I think the move to safer code through Rust and other alternatives is a nice breath of fresh air, I doubt you can get these kinds of optimization without using unsafe code in Rust. These optimized implementations often require some kind of safety-bypassing memory modifications to work as efficiently ad they do.

There's a reason https://github.com/libjpeg-turbo/libjpeg-turbo/tree/main/sim... is filled with assembly files with conditional loading.

Sure. You'll see it very often in codec implementations. From rav1e, a fast AV1 encoder mostly written in Rust: https://github.com/xiph/rav1e/tree/master/src/x86

Large portions of the algorithm have been translated into assembly for ARM and x86. Shaving even a couple percent off something like motion compensation search will add up to meaningful gains.

Or the current reference implementation of JPEG: https://github.com/libjpeg-turbo/libjpeg-turbo/tree/main/sim...

zune-jpeg is 1.5x to 2x faster than jpeg-decoder and is on par with libjpeg-turbo.

This is interesting from the standpoint of how new JVM features can be used to improve performance (what I presume the article's main purpose to have been), but the image processing improvement itself isn't head-turning. Also, we've found that libjpeg-turbo (https://libjpeg-turbo.org/) is ~5x (IIRC, can re-run my JMH benchmark if anyone wants me to) as fast for decoding JPEGs as ImageIO, so we wouldn't even benefit from this change in 21 much.

libjpeg-turbo: https://github.com/libjpeg-turbo/libjpeg-turbo/blob/main/simd/x86_64/jsimdcpu.asm

libjpeg-turbo

For all but the simplest formats (basically BMP), the difficulty of implementing encoding/decoding from scratch is significant - well beyond a beginner's ability, and challenging/time-consuming even for senior developers. So, libraries are used in practice - e.g. libpng and libjpeg-turbo.

Happy to see this on HN =). Lunatik’s main author here. AMA.

Please feel welcome to join us on Matrix [1] as well.

[1] https://matrix.to/#/#lunatik:matrix.org

There is this list of 15-minute bugs that should be easy to tackle https://bugs.kde.org/buglist.cgi?bug_severity=critical&bug_s...

Also strarting on smaller KDE applications is usually a great way to start, For example the Plasma widgets/applets or KDE games or educational applications.

You can join the New Contributors char room on Matrix to get help with starting out https://matrix.to/#/#new-contributors:kde.org

There's also https://matrix.to/#/#review-requests:nixos.org

Hi, I'm the Thib person mention in this article, and I agree that QA is super important. I can mostly talk about matrix.org, since I have little power over the Element clients. Disclaimer though: I'm technically employed by Element (to make paperwork simpler since I'm France-based, Element has an entity in France, and the Foundation is UK-based), but I'm working for the Foundation full time.

This kind of article is super valuable since it gives us the perspective of a new user. I opened https://github.com/matrix-org/matrix.org/issues/2178 to translate the gripes mentioned in the issue into actionable items for us. I took action on the most urgent one (updating the Try Matrix page), but want to take the time to go beyond the surface symptoms and address the root cause of the other gripes.

On the Foundation side, we're a small but mighty team of four. The website is currently maintained part time by me and a volunteer who is doing an excellent job at it.

As I wrote recently in a blog post "Tracking what works, not people" (https://ergaster.org/posts/2024/01/24-tracking-what-works/), I would love to have the resources to conduct user research and user testing on the website but I unfortunately don't. We deployed privacy-preserving analytics to see where people drop and what confuses them. It's not nearly as good as proper QA and user testing, but that's what we can afford for now.

Overall I'm grateful to the author for documenting their frustration, and even more grateful for reacting constructively to our responses and integrating them in the blog post! One of the strengths of open source is to find and address issues collectively. I consider this blog post to be a good open source contribution.

If people around believe in our mission and want to help us with their brainpower, I invite them to join our "Office of the Matrix.org Foundation" room: https://matrix.to/#/%23foundation-office:matrix.org

For those aligned with our mission and who want to support us financially, the https://matrix.org/support/ page should give you all the information you need to help us out.

https://matrix.to/#/#openbao-general:chat.lfx.linuxfoundatio...

Hi all,

This project release is a long time coming. It was a big uphill battle, and by far my largest endeavor so far. I built it for Sandstorm because I believe in Sandstorm's model, and I wanted to show that there's still life and potential in it. If you're inspired, joining our OpenCollective would be really helpful: https://opencollective.com/sandstormcommunity (keeping in mind that Sandstorm has now moved from its original leadership to a community project https://sandstorm.org/news/2023-11-03-from-io-to-org).

You can also join our mailing list or connect on the fediverse: https://sandstorm.org/community (The IRC link is outdated, we've effectively moved to Matrix for now due to the libera.chat split: https://matrix.to/#/#sandstorm:libera.chat)

Also: I'm open for hire! You can see some of my skills in putting things together in this blog post. I'd love to work in something FOSS or OSM related, but not a requirement. I mostly do Python and Golang, with a bit of Haskell under my belt. Other projects and resume here: https://github.com/orblivion/me

I really appreciate you sharing your concerns, and for all the hope and energy you've put into Matrix to date. Very much to your point, we're not yet in a state where I recommend Matrix to friends and family. Right now I only use it with people in FOSS and other circles where folks are a little more patient with the tech.

Only time will tell, and of course I'm biased as the Matrix.org Foundation's Managing Director, but I think there's good reason to remain hopeful:

The spec continues to evolve with major improvements expected in feature set and performance in the next year as we get to the 2.0 spec release, the Foundation is staffing up and beginning to fundraise, we're on the cusp of holding our first ever community elections to seat a Governing Board, and adoption has continued doubling on an annual basis.

I invite you and anyone else who is invested and/or concerned to join us in the Foundation's new office room – it's a way to get a view into ongoing activities, ask questions, provide direct feedback, and celebrate all the little wins on our way to collective success: https://matrix.to/#/#foundation-office:matrix.org

Cool! Just in case you haven't come across this, we've got a (rather quiet lately) chat that might be useful.

https://matrix.to/#/#usb-rs:matrix.org