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Cake day: July 20th, 2023

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  • I should elaborate on why the “Peak white” stuff is wrong, they give this math here for mapping linear luminance. This can be really confusing, “what do we map the references to” well if PQ “graphics white” is 203, should we map sRGB to 203? clearly not, at least not always as implied by BT.2408.

    the question as to what we map SDR content to in an HDR space is complex, and in many cases almost certainly not some number that we can do 1:1 mapping with, which is why specifications for inverse tonemapping exist. for instance BT.2446 defines multiple tone mapping algorithms to go from SDR->HDR->SDR or HDR->SDR->HDR or any step inbetween with minimal content loss and fidelity loss.

    we cannot do a simple one size fits all function and expect everything to be hunky dory


  • This makes a numerous amounts of incorrect assumptions.

    For one it assumes all sRGB monitors utilize gamma2.2 for decoding images. This is bluntly put, completely wrong. A large amount of displays utilize the inverse OETF (the peicewise srgb transform) for decoding sRGB. (for some more information from a somewhat authoritative body, filmlight’s “srgb we need to talk” video on youtube goes more indepth but TLDR is 25-50% of displays use the inverse sRGB oetf)

    this is why windows HDR uses the inverse oetf. Decoding content graded on a pure 2.2 display with the inverse oetf is way better then decoding content graded on an inverse oetf display with a pure 2.2. Windows took the safe route of making sure most content looks at least OK. I would not say that windows HDR is wrong, it’s not right, but it’s not wrong either. this is just the mess that sRGB gave us.

    Another time you should be using the inverse sRGB OETF to linearize content when the original content was encoded using the sRGB oetf and you want to go back to that working data, but this applies less to compositors and more to authoring workflows.

    Another wrong assumption

    When you use Windows 11 on a desktop monitor and enable HDR, you get an “SDR content brightness” slider in the settings - treating HDR content as something completely separate that’s somehow independent of the viewing environment, and that you cannot adjust the brightness of. With laptop displays however, you get a normal brightness slider, which applies to both SDR and HDR content.

    People have been adjusting monitor brightness for ages. Sometimes manually, sometimes with DDC etc.

    Another issue that is brought up is “graphics white” BT.2408 is a suggestion, not a hard coded spec, many different specs or suggestions use a different “graphics white” value. A good example of this is JXL. 2408 also very explicitly says ‘The signal level of “HDR Reference White” is not directly related to the signal level of SDR “peak white”.’

    this is important to note because this directly contradicts the some of the seemingly core assumptions made in the article, and even some of the bullet points like “a reference luminance, also known as HDR reference white, graphics white or SDR white” and “SDR things, like user interfaces in games, should use the reference luminance too”

    if your application has some need to differentiate between “SDR” and “HDR” displays (to change the buffer format for example), you can do so by checking if the maximum mastering luminance is greater than the reference luminance

    This needs to be expanded upon that this does NOT correlate to what the general user understands HDR and SDR to be. HDR and SDR in the terms of video content is no more then a marketing term and without context it can be hard to define what it is, However it is abundantly clear from this quote here that how they are interpreting HDR and SDR (which is a very valid technically inclined way of interpreting it) does NOT fall inline with general user expectation.

    Anyone reading this article should be made aware of this.











  • As someone who used to sell computers to elderly and people who are generally non tech literate, as well as ran computer literacy courses;

    ChromeOS + something like flatpak. I don’t think anything else will really work in the current linux world. Holding on hope for Cosmic based DE.

    A Distro must have

    • Easy AND reliable DE. KDE has been way too buggy and gnome has been way too hard for my parents to use. Old people often have an extremely hard time learning, it needs to replicate what they already know which is either going to be Windows or OSX most likely. Cosmic should be able to do both nicely when ready.

    Reliability is so fucking key here I can not understate it. The computer glitching out is entirely unacceptable. They will not be able to do any debugging nor will you likely be on call 24/7 to fix their issues. They also need security so you can’t just “set and forget” either with no updates in a false sense of stability. Older folk copy and paste shit. Permissions and stability is key here. Flatpak has a lot of potential but it’s not there yet.

    No real time AV really hurts here.

    • Extremely strong app selection with either android or wine app support. Wine is the most preferable. A lot of people are reliant on windows programs for things like tax filing and all sorts of stuff like crochet software and what not. Android apps however can often be good enough and are extremely simple so with a little help, and you will need to help, they can get by with android app support.

    • A11y, screenreaders, OSKs, maginifers etc. We need all of it if we want to fit the “generic elderly support”

    • Good performance. Elderly people do NOT like updating systems, Their systems will likely be old. And well they are old too. If a system is slower then what they are used to, and generally non responsive, they may think the bloody thing is broken. cough cough gnome cough cough

    I genuinely do not that that any DE let alone distro is an acceptable daily driver for “general people” because general people have such a wide variety of use cases and needs. Some folk need crochet and tax software, some folk need CNC software like stitchfiddle, Some need magnifier glasses and speech to text. and man, this is only the more common of things i’ve seen.

    Remeber folk, a PC that does 99% of what people generally need, does not mean that it will fit the needs of 99% of people. Here is hoping to a bright future, but I don’t think it will be a close one.