Um, apparently we're reading it differently because I've read that several times and I don't see that? Can you find a source that specifically says that more bits can be applied within the same color space within the HDR spec? I've been trying to find something that specifies it clearly and struggling myself!
EDIT: I finally asked someone knowledgeable (the usual
) for details. And we were kind of both right in a way?
So, if one tried to simply use the additional bits for more data within the SDR color space, it wouldn't work. The spec, and thus displays, are designed so that each "step" of each color in SDR and HDR are the same size, and HDR just goes further (wide gamut). So all the additional data in HDR is put toward colors beyond SDR, and SDR itself is unchanged and fits inside of the HDR spec. This makes perfect sense from a backwards compatibility standpoint, as well as a display manufacturer standpoint. It's so easy to play SDR content on HDR systems because the HDR display can just show the limited gamut as is on its screen, and the rest of the wide gamut is just unused. Simple! But this means that reducing banding by the simple method you described doesn't really work, since you can't just give more bits to the same color range and have it work on a display.
Hoooweeeever, one could use tonemapping (using the full range of brightness and other options available, not just color) to convert the SDR colors into the HDR color space while preserving its original colors. And then you could use interpolation to smooth between the steps to reduce banding. This would be additional inbetween stage for rendering the image, requiring processing power and adding some latency, but that would essentially get what you want: more data within the same colorspace. However, there are problems when doing this, as the interpolation can fail and banding can actually look worse. He explained why it fails but it was a big long explanation and I've since forgotten the details, so I won't recite them here. Anyway, basic interpolation probably wouldn't work, and it would need a more complex solution, hopefully one that doesn't impact the look of the title beyond fixing banding. So it's possible, just really difficult!
EDIT: I finally asked someone knowledgeable (the usual
) for details. And we were kind of both right in a way?So, if one tried to simply use the additional bits for more data within the SDR color space, it wouldn't work. The spec, and thus displays, are designed so that each "step" of each color in SDR and HDR are the same size, and HDR just goes further (wide gamut). So all the additional data in HDR is put toward colors beyond SDR, and SDR itself is unchanged and fits inside of the HDR spec. This makes perfect sense from a backwards compatibility standpoint, as well as a display manufacturer standpoint. It's so easy to play SDR content on HDR systems because the HDR display can just show the limited gamut as is on its screen, and the rest of the wide gamut is just unused. Simple! But this means that reducing banding by the simple method you described doesn't really work, since you can't just give more bits to the same color range and have it work on a display.
Hoooweeeever, one could use tonemapping (using the full range of brightness and other options available, not just color) to convert the SDR colors into the HDR color space while preserving its original colors. And then you could use interpolation to smooth between the steps to reduce banding. This would be additional inbetween stage for rendering the image, requiring processing power and adding some latency, but that would essentially get what you want: more data within the same colorspace. However, there are problems when doing this, as the interpolation can fail and banding can actually look worse. He explained why it fails but it was a big long explanation and I've since forgotten the details, so I won't recite them here. Anyway, basic interpolation probably wouldn't work, and it would need a more complex solution, hopefully one that doesn't impact the look of the title beyond fixing banding. So it's possible, just really difficult!
![[Image: RPvlSEt.png]](https://i.imgur.com/RPvlSEt.png)
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