XSF Discussion - 2022-09-07

  1. Daniel

    a probably very stupid question. looking at https://datatracker.ietf.org/doc/html/draft-schmaus-kitten-sasl-ht-07 what does `initiator-hashed-token := HMAC(token, "Initiator" || cb-data)` mean? || is a concatination so the bytes for cb-data the string "Initiator" are just added to the bytes of "Initiator" - but what does `token,` mean? isn’t that another concatination? or in other words what is the difference between` token || "Initiatior" || cb-data` and `token, "Initiatior", cb-data`

  2. Zash

    HMAC takes a key and a message

  3. Zash

    So, one is `token`, the other is `"Initiator" || cb-data`. Good luck guessing which is which! :)

  4. Daniel

    oh ok. I thought it's just hash(…)

  5. Zash

    No, it's two hashes in series with some padding and stuff.

  6. Daniel

    but yeah that makes sense. thank you

  7. Zash

    https://en.wikipedia.org/wiki/Hmac#Definition but your crypto library really should provide it

  8. goffi

    Hi. What would be the recommanded image format nowadays in a XEP for lossy compression of images (mostly photos)? I'm thinking mostly about patent issues. Is JPEG OK to use? WebP?

  9. Link Mauve

    goffi, JPEG is still the only one with widespread support sadly. :(

  10. Link Mauve

    WebP is often not an improvement over JPEG, and then you have formats like AVIF which are, but with exactly no support on mobile.

  11. Link Mauve

    There are JPEG features you should avoid if you’re worried about patents, but most implementations don’t support them anyway, so if you stay with JPEG Baseline you’re good.

  12. goffi

    Alright, thanks Link Mauve

  13. Link Mauve

    If you know your recipient is on either Windows or Linux, AVIF is an option.

  14. Link Mauve

    Otherwise, use JPEG.

  15. goffi

    Link Mauve: it's for a protoXEP, thus is should be available on as most plateform as possible, thus I'll go with JPEG

  16. singpolyma

    JPEG for photo for sure I think. WebP for everything else (stickers, animations, etc)

  17. Link Mauve

    I think most Linux distributions still don’t ship with WebP support out of the box.

  18. Link Mauve

    I’d recommend PNG and GIF instead, if you want widespread support.

  19. moparisthebest

    It's ok Linux users are used to things being broken until they install the right stuff :D

  20. singpolyma

    I mean, WebP works in Firefox on Debian Stable

  21. singpolyma

    it's not exactly new

  22. singpolyma

    PNG can't animate, APNG never got good support, and GIF looks like garbage, so for animations especially WebP is very nice

  23. Link Mauve

    singpolyma, Firefox uses it explicitly, but most XMPP clients (AFAIK) are not web clients.

  24. Link Mauve

    singpolyma, for large animations you want a video format anyway.

  25. singpolyma

    Sure, the clients may need to add support, will depend on how they are rendering images etc

  26. singpolyma

    WebP *is* a video format, luckily :)

  27. Link Mauve

    Actually no.

  28. moparisthebest

    What linux desktop client supports inline gif even?

  29. singpolyma

    moparisthebest: I'm not aware of one

  30. Link Mauve

    It’s using VP8 for its lossy compression, but only supports keyframes so you will get much bigger files if only small parts change frame-to-frame.

  31. Link Mauve

    moparisthebest, any based on GTK I think?

  32. moparisthebest

    Not Dino I think

  33. trung.fun

    last time I checked, Dino 0.3 use VP8

  34. Link Mauve

    trung.fun, video calls in Dino go through Gstreamer, while image decoding goes through gdk-pixbuf.

  35. Link Mauve

    Two different libraries with different support for different formats.

  36. larma

    Dino supports gif fine, it just restricts itself to displaying the first frame only. Same for all other animated image formats that gdk pixbuf supports.

  37. larma

    pixbuf does support animated images, but who would want those to be actually animated?

  38. Link Mauve


  39. edhelas


  40. larma

    Also, for anything that is not a video, just use animated svg please! Much smaller files and even scale perfectly to every screen resolution and hidpi devices

  41. Link Mauve


  42. Link Mauve

    Also, mobile client devs, please add support.

  43. edhelas

    <iframe> is what you're looking for, with animated CSS

  44. larma

    I can do css animations on svg without iframes

  45. larma

    that's how all animations in gtk are done already 🙂

  46. singpolyma

    I'd be happy to use animated SVG if I'm authoring something new, just depends on the kind of content

  47. edhelas

    One of the issue that I have with stickers and animated stickers is more getting nice content for me, so finding artists that can craft content that I can package in my client

  48. Zash

    This is why stickers must come in packs from a sticker store where you buy them so you can pay the artists!!

  49. Zash

    Thus we must launch XMPPCoin!

  50. singpolyma

    I'm happy to pay the artist, but yeah there's so many sticker images around on the web I'm not sure if making more is the priority? But I guess it all depends on users and what they need

  51. Link Mauve

    I’d really like to have a sticker pack using animated SVG, but almost all of my contacts are using Android which doesn’t support this format. :(

  52. Link Mauve

    It doesn’t even support normal SVG, not even SVG Tiny…

  53. singpolyma

    there are libraries for it I'm sure

  54. Link Mauve

    Sure, but how many additional MiB are you ready to ship with your application?

  55. Zash

    Just ship a full browser!

  56. Link Mauve

    For such a fringe feature, which is fringe because you don’t.

  57. trung.fun

    > Two different libraries with different support for different formats. I don't know what it does underneath, but it takes nearly half a minute to launch.

  58. trung.fun

    Guys, if u want wide adoption as quickly as u can, stick with jpeg, png and gif. You can come back and upgrade all them codec later. (I would be quite impressed if you make a client that has support for Apple Prores444 but hey) Anyway, I think lets not create more issues for the people who want to try xmpp for the first time.

  59. singpolyma

    edhelas: do you have ideas of stickers you'd like to see, or you just want to hand a budget to an artist and ask them to go nuts?

  60. edhelas

    > Just ship a full browser! That's the spirit

  61. edhelas

    I already did that a few times in Movim

  62. millesimus

    The sticker XEP opts for a kind of distributed sticker storage fed by the users… so, if that's supported, you just scrape signalstickers.com (they have a python library), and unleash Sticker Hell™️.

  63. singpolyma

    millesimus: yes, for sure. lots of places we can get them from

  64. singpolyma

    on android the users can also get sticker packs right in their keyboard

  65. millesimus

    Iirc, Samsung allows you to combine emojis to create stickers. Quite funny.

  66. mjk

    millesimus, suddenly, Spore?

  67. Zash


  68. moparisthebest

    Boo IETF

  69. singpolyma

    At least they're not moving to discord?

  70. singpolyma

    I honestly didn't know there were IETF channels