The pdf association is still running experiments on whether or not to support custom dictionaries based on real life workloads gains.

So it might land in the spec once it has proven if offers enough value

You can read about it here https://pdfa.org/brotli-compression-coming-to-pdf/

That mentions zstd in a weird incomplete sentence, but never compares it.

They don’t seem to provide a detailed comparison showing how each compression scheme fared at every task, but they do list (some of) their criteria and say they found Brotli the best of the bunch. I can’t tell if that’s a sensible conclusion or not, though. Maybe Brotli did better on code size or memory use?

Hey, they did all the work and more, trust them!!!

> Experts in the PDF Association’s PDF TWG undertook theoretical and experimental analysis of these schemes, reviewing decompression speed, compression speed, compression ratio achieved, memory usage, code size, standardisation, IP, interoperability, prototyping, sample file creation, and other due diligence tasks.

I love when I perform all the due diligence tasks. You just can't counter that. Yes but, they did all the due diligence tasks. They considered all the factors. Every one. Think you have one they didn't consider? Nope.

But they didn't write "all". They wrote "other", which absolutely does not imply full coverage.

Maybe read things a bit more carefully before going all out on the snide comments?

It implies potential coverage of anything one could bring up. It creates a similar impression in my mind, because it becomes easy to claim you already considered something.

In fact, they wrote "reviewing […] other due diligence tasks", which doesn't imply any coverage! This close, literal reading is an appropriate – nay, the only appropriate – way to draw conclusions about the degree of responsibility exhibited by the custodians of a living standard. By corollary, any criticism of this form could be rebuffed by appeal to a sufficiently-carefully-written press release.

No this feature is coming straight from the PDF association itself and we just added experimental support before it's officially in the spec to help testing between different sdk processors.

So your comment is a falsehood

It's prototypish work to support it before it land's in the official specification. But it will indeed take some adoption time.

Because I'm doing the work to patch in support across different viewers to help adoption grow. And once the big opensource ones ship it pdfjs, poppler, pdfium, adoption can quickly rise.

There are old devices where the viewer can’t be patched. That’s killing one of the main features of PDF

Part of this feature is the release of the repo https://github.com/itext/itext-eu-trusted-lists-resources which contains the trusted European certificates and is maintained and kept up to date by the iText development team. It's free and MIT licensed so go use it if you need it!

Yes, I was planning to do that in the coming weeks when I find a few hours of time. And didn't know about the second part quite interesting, I'll look into it thank you

Does it support tagged documents and PDF2.0 as well?

I use it literally everyday, not only to see the structure but also modify pdf's on the fly when I need to tests edge cases.

Stuff I do with it: Modify content streams, extract images/content, just investigate general structure of the pdf documents, remove pages, repair documents,... it's literally a swiss army knife when working with pdf's