Skip to main content


The current JPEG XL decoder in #Firefox apparently consists of more than 100,000 lines of multi-threaded C++

For just decoding an image format.

Not sure what it says about the format, the implementation and the Internet at large.

github.com/mozilla/standards-p…

This entry was edited (2 months ago)
in reply to Thomas Depierre

(i will keep banging the drums that most of the FOSS "supply chain" fear could be handled by investing more in programming language tooling, as Rust demonstrate, and that it would be a small overall cost for massive pay off...)
in reply to Thomas Depierre

@Di4na possibly: I believe Rust is generally a good thing for most things, but I believe the Rust ecosystem with cargo and bazillions of always-updatiing tiny dependencies risk adding friction and at least complicates the equation quite a lot
in reply to daniel:// stenberg://

This is my biggest worry too: they essentially copied the NPM package management model and practices. Good for short term productivity, but I worry that it causes significant long-term maintainability problems.

And everything is version 0.x, in part due to technical limitations of Cargo: moving out of 0.x is a breaking change, so if you have users on 0.x (which Cargo encourages by adding semver compatibility rules which make 0.x.a compatible with 0.x.b), moving out of 0.x breaks them.

This entry was edited (2 months ago)
in reply to daniel:// stenberg://

@Di4na
I'm not sure it is a tooling issue. I find cargo to be a great tool, and it have a lock file to let you update deps in a controlled fashion.
I think this comes down to a cultural issue, where the rust community, much like the JS community, put every little utility function in it's own library. Hence, you tend to get a gazillion small dependencies that is hard to keep track of.
in reply to daniel:// stenberg://

i mean yes, but at least the compiler is a tool.

While C and others are uh. Well some are finally realising they have users

in reply to daniel:// stenberg://

That sounds like an atrocity. But if it shows ads faster...uhm...nevermind.😌
in reply to daniel:// stenberg://

yeah, kinda puts into perspective all the 'negative feedback' the Chrome team received for removing JPEG-XL support. I wouldn't want to have such a monstrosity in my code base either, no matter what advantages the actual encoding might have over existing formats.
in reply to daniel:// stenberg://

Well, it seems that your point is "Firefox consists of bad code", whereas I believe that the conclusion from the post should be "The library is bad code, which is why we are not using it in production. We'd be happy to look at their rust implementation, when it's possible"

(footnote: "bad code" being an abbreviation of "100k multi-threaded C++")

in reply to Frederik Braun �

@freddy you're reading too much into my words. I'm just amazed by how large the existing JPEG XL decoder is.

And I don't think I am alone.

in reply to daniel:// stenberg://

Oh, OK. Sorry for misreading then. I'll back off. 🙂

(And yes, the existing library is... 🤯)

in reply to daniel:// stenberg://

@freddy

and "uses" in this case means "has it available behind a feature flag in their nightly builds, and does not ship it to normal users because of this very issue"

in reply to daniel:// stenberg://

We had 100kloc C++ in a smart radiator valve that saved a bunch of extra energy.

I think it is just a reflection that extracting efficiency requires complexity.

This entry was edited (2 months ago)
in reply to daniel:// stenberg://

It's a good hot take, but what amazes me most is the replies so far immediately jumping to conclusions with biased gut reactions as if their identity is tied to one or the other camp.
in reply to daniel:// stenberg://

And, just wondering:
How many of those lines are for handling security issues such as boobytrapped JPEGs?
How many lines do the other HTML rendering engine use for the same function?
The graphical web has many sins to make amends for!
in reply to daniel:// stenberg://

I really don't envy the people who'd have to rewrite that monstrosity.
See flak.tedunangst.com/post/on-bu… by @tedu for the current state of the art method of decoding jpegxl safely, which is both hilarious and sad.
@tedu
in reply to daniel:// stenberg://

Wait, so JPEG XL isn't completely dead? That's probably not what you meant to communicate but I'm so happy to hear that

fwiw I think that LOC of the reference implementation doesn't really say anything about anything - even if Firefox "adopted" it, which feels like a sensible choice given the state of things

in reply to daniel:// stenberg://

could isolate the decoder in a WASM runtime and only start the rewrite if and when the format becomes popular enough :-)
This entry was edited (2 months ago)
in reply to daniel:// stenberg://

browser vendors should coordinate which subset of JPEG XL they want to support, and only this part of the standard needs to get implemented.

I remember JPEG and that you could never use progressive JPEGs. Some programs even offered an “export for web” feature so that you wouldn't use any unsupported JPEG features.

in reply to daniel:// stenberg://

To put in perspective:
- JPEG: libjpeg 6b encoder+decoder: 24,200 lines of C
- JPEG: libjpeg-turbo encoder+decoder: 127,000 of C and ASM (multi architectures)
- JPEG2000: openjpeg encoder+decoder: 50,000 lines of .C
- JPEG2000: Kakadu commercial encoder+decoder: 214,000 lines of C++ (only coresys component)
- libjxl: 150,000 lines for the core library, encoder+decoder (deps excluded)
(All above includes blank lines + inline doc)
So this is pretty much standard for a modern codec

daniel:// stenberg:// reshared this.

in reply to daniel:// stenberg://

I wonder if it's turing complete... something something Pegasus 0-click iMessage exploit.
in reply to daniel:// stenberg://

I think it is a bit misleading (and arguably unfair) to attribute this to Firefox specifically: this is the reference jpeg-xl implementation, originally created and maintained by Google, and in widespread experimental use across all kinds of browsers, including Chromium, Safari, Edge and more
This entry was edited (2 months ago)