As to what was to be debunked, the presentation not only fails to set out a thesis in the introduction, it doesn't even beg a question, so you've got to watch hours to get to the point: SDR and HDR are two measurement systems which when correctly used for most cases (legacy and conventional content) must produce the visual result. The increased fidelity of HDR makes it possible to expand the sensory response and achieve some very realistic new looks that were impossible with SDR, but the significance and value of any look is still up to the creativity of the photographer.

This point could be more easily conveyed by this presentation if the author explained in the history of reproduction technology, human visual adaptation exposes a moment by moment contrast window of about 100:1, which is constantly adjusting across time based on average luminance to create an much larger window of perception of billions:1(+) that allows us to operate under the luminance conditions on earth. But until recently, we haven't expected electronic display media to be used in every condition on earth and even if it can work, you don't pick everywhere as your reference environment for system alignment.

(+)Regarding difference between numbers such as 100 or billions, don't let your common sense about big or small values phase your thinking about differences: perception is logarithmic; it's the degree of ratios that matter more than the absolute magnitude of the numbers. As a famous acoustics engineer (Paul Klipsch) said about where to focus design optimization of response traits of reproduction systems: "If you can't double it or halve it, don't worry about it."

You didn’t need new displays to make use of it. It wasn’t suddenly brighter or darker.

The change from 15 to 16 bit color was at least visible because the dynamic range of 16-bit color is much lower than 30-bit color, so you could see color banding improve, but it wasn’t some new world of color, like how HDR is sold.

Manufacturers want to keep the sales boom that large cheap TVs brought when we moved away from CRTs. That was probably a “golden age” for screen makers.

So they went from failing to sell 3D screens to semi-successfully getting everyone to replace their SDR screen with an HDR screen, even though almost no one can see the difference in those color depths when shown with everything else being equal.

What really cheeses me on things like this is that TV and monitor manufacturers seem to gate the “blacker blacks” and “whiter whites” behind HDR modes and disable those features for SDR content. That is indefensible.

Meanwhile, YouTube is incredibly sluggish on my computer, with visible incremental rendering of the page UI, and seeking in a video easily takes 500~1000 ms. It's an embarrassment that the leading video platform, belonging to a multi-billion-dollar company, has a worse user experience than a simple video file with only the web browser's built-in UI controls.

I think the point that SDR inputs (to a monitor) can be _similar_ to HDR input to monitors that have high dynamic ranges is obvious if you look at the maths involved. Higher dynamic gives you more precision in the information, you can choose to do what you want with it : higher maximum luminosity, better blacks with less noise, more details in the middle etc.

Of course we should also see "HDR" as a social movement, a new way to communicate between engineers, manufacturers and consumers, it's not "only" a math conversion formula.

I believe we could focus first on comparing SDR and HDR black and white images, to see how higher dynamic range only in the luminosity is in itself very interesting to experience

But in the beginning he is saying the images look similar on both monitors. Surely we could find counter examples and that only applies to his cinema stills ? If he can show this is true for all images then indeed he can show that "SDR input to a HDR monitor" is good enough for all human vision. I'm not sure this is true, as I do psychedelic animation I like to use all the gamut of colors I have at my hand and I don't care about representing scenes from the real world, I just want maximum color p0rn to feed my acid brain : 30 bits per pixels surely improve that, as well as wider color gamut / new LEDs wavelengths not used before

I wish he shared his code though. Part of the problem is he can't operate like a normal scientist when all the best color grading tools are proprietary.

I think it would be really cool to make an open source color grading software that simulates the best film looks. But there isn't enough information on Yedlin's website to exactly reproduce all the research he's done with open source tools.

Secondly, Rec. 2100 defines more than just a colorspace. A coordinate triple in the Rec. 2100 colorspace does not dictate both luminance and chromaticity. You need to also specify a _transfer function_, of which Rec. 2100 defines two: PQ and HLG. They have different nominal maximum luminance: 10,000 nits for PQ and 1,000 nits for HLG. Without specifying a transfer function, a coordinate triple merely identifies chromaticity. This is true of _all_ color spaces.

On the other hand his feet/meters analogy is excellent and I’m going to steal it next time I need to explain colorspace conversion to someone.

Back in the days I made ray tracers and such, and going from an internal SDR representation to an internal HDR representation was a complete game changer, especially for multiple reflections. That was a decade or more before any consumer HDR monitors were released, so it was all tonemapped to SDR before displaying.

That said, I would really like to see his two monitors display something with really high dynamic range. From the stills I saw in the video, they all seemed quite limited.

Anyway, something to watch fully tomorrow, perhaps he addresses this.