Quote:
Originally Posted by jmone
I use my HTPC / JVC with a mix of media, BD / UHD with HDR / TV / Gaming etc and at frame rates from 23.976 to 59.94. If I want HDR working at 50/59.94 the HDMI limit will be 8-Bit at 4:4:4. I "presume" that once the HDR -> SDR work is done, I can just set my bit depth to 8-Bit and let madVR do the HDR -> SDR for content with HDR and like the non HDR material it should all "just work" with JVC at all frame rates..... or am I missing something that needs higher than 8-Bit?
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UHD Bluray content is 10bits, so while you can dither it to 8bits and get very good results, why not make the most of the fact that the JVCs are native 12bits panels from input to panel and ask MadVR to dither to 10bits instead?
The drivers switches automatically between RGB 4:4:4 12bits 23p (for video content) and RGB 4:4:4 8bits 60p for 60p video or games, so why not take advantage of this?
Quote:
Originally Posted by huhn
what's wrong/limitation with running in native gamut and letting a 3D LUT take care of it?
if you want the "best" PQ a 3d lut is the way to go.
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Projectors lose a lot of native contrast when you open the iris to get more brightness. So you're leaving A LOT of performance if you use the same native gamut for calibrating both HDR and SDR.
If you use your HDR calibration (say DCI-P3 with the P3 filter on for the wider gamut and the iris fully open to get max brightness for HDR), the SDR calibration is non-optimal (with raised black levels and about half of the native contrast you could get).
Plus in that case you get too much brightness for SDR in a dedicated room, so you have to either use a 3D LUT that limits the brightness (hence kills your contrast) or get blinded by a reference white at 100nits or more for SDR, which is about twice as much as what we're aiming for in a dedicated room.
For example, in my case I get around 100nits with the iris fully open in DCI-P3, and only around 40,000:1 on.off. The black floor is also raised.
If I use this calibration for HDR, I get blinded with 100nits reference white, and I leave a lot of on/off and black levels on the table.
With my SDR calibration, I aim for 50nits reference white, I lower the iris down to -10, it gives me double native on/off contrast (around 80,000:1) and a far better black floor.
I do use a 3D LUT for each calibration, but they cannot apply to the same baseline without losing a lot of performance in one mode or the other.