Tue Oct 10, 2017 8:20 am
Hello guys; haven't been posting on this forum for a long time (meaning I haven't had too many problems with transition to v.14 
. But I do have a serious workflow problem (same in the 12.5 and 14) that I'd need your help with... So here I go:
As some of you may remember, ever since I started using Resolve over a year ago, I have been grading my FS7's XAVC-I, Shogun Inferno's DNxHR and recently also GH5's H.264 footage for PQ, using RCM and sometimes ACEScc. I'd say almost all my footage is log (S-Log2/3 from Sony and V-Log L from the little Panasonic), always 10-bit 4:2:2 - nothing less than that is enough for successful HDR10 grading! But I've started to observe some problems with my highlights, and particularly the sky area (clear blue, or overcast with white or gray clouds - in the outdoor uncontrolled lighting these are usually the brightest part of the picture). Namely, it's very difficult for me to retain color and detail information in the sky area; I must keep the level down to see the blue sky color and details in the clouds, because all this will quickly and suddenly turn into ugly, gray area with no color or detail at all... My Samsung SUHD monitor is rated over 1,000 nits of maximum brightness, and yet - with some footage, particularly S-Log3 - it can happen at levels quite a bit lower than this....
So far, my testing indicate one of the following might be the culprit (both software and/or hardware):
a. the way highlights in Log footage are decoded in Resolve (be it RCM, ACEScc, or even LUT-based workflows such as Loagrist - not much can be done about it, but do you encounter the same behavior?)
b. my Decklink 12G video card: colors in highlights are turning into light grey areas easily and suddenly, even when the levels not too high at all (BMD Support - if you're reading this - do you think my card might be malfunctioning?)
c. my Samsung SUHD TV, used as a grading monitor: it's said to have maximum brightness of more than 1,000 nits but when highlights occupy to large an area, it turns light grey without details but with lots of compression artifacts (yeah I know - calibrating should be repeated - but could the difficulty with retaining highlight detail & color indicate some hardware problem in my TV?)
Before you guys point at tone of the above as the most probable reason, let me show you the only way I can alleviate the problem with Resolve grading controls:
As you can see, the "Highlight" control must be turned down considerably to protect sky color & details; it doesn't seem to decrease Gain too much (so the overall brightness is not overly reduced), while preventing the abovementioned turning of highlights into one detail- and color-less area. BTW, in this particular example I also elevated the Shadows - but that's because the scene has been back-lit considerably. As can be seen in the screen grab below, the clouds' color and detail has been retained - while the scopes still reach 1,000 nits with their peaks:
And the resulting grade (in its basic stage, ready for fine-tuning) is OK in that the sky is not overblown into detail-less gray while the shadows are not too dark, with details but not noisy:
I need to add that this kind of problem with retaining (otherwise completely legal in HDR10) highlights' detail & color has been increasing lately; this would indicate hardware rather than software problem... Also, in your grading experience much deeper than my own, is a need for such intensive tuning of Shadows and Highlights considered normal - or very rare at all? Your answer to this question would help me tremendously, as at beginning of my using Resolve on this particular hardware I never even touched those controls, whereas dialing the Highlights down has become more and more necessary lately... Looking forward to your suggestions and opinions,
Piotr
. But I do have a serious workflow problem (same in the 12.5 and 14) that I'd need your help with... So here I go:As some of you may remember, ever since I started using Resolve over a year ago, I have been grading my FS7's XAVC-I, Shogun Inferno's DNxHR and recently also GH5's H.264 footage for PQ, using RCM and sometimes ACEScc. I'd say almost all my footage is log (S-Log2/3 from Sony and V-Log L from the little Panasonic), always 10-bit 4:2:2 - nothing less than that is enough for successful HDR10 grading! But I've started to observe some problems with my highlights, and particularly the sky area (clear blue, or overcast with white or gray clouds - in the outdoor uncontrolled lighting these are usually the brightest part of the picture). Namely, it's very difficult for me to retain color and detail information in the sky area; I must keep the level down to see the blue sky color and details in the clouds, because all this will quickly and suddenly turn into ugly, gray area with no color or detail at all... My Samsung SUHD monitor is rated over 1,000 nits of maximum brightness, and yet - with some footage, particularly S-Log3 - it can happen at levels quite a bit lower than this....
So far, my testing indicate one of the following might be the culprit (both software and/or hardware):
a. the way highlights in Log footage are decoded in Resolve (be it RCM, ACEScc, or even LUT-based workflows such as Loagrist - not much can be done about it, but do you encounter the same behavior?)
b. my Decklink 12G video card: colors in highlights are turning into light grey areas easily and suddenly, even when the levels not too high at all (BMD Support - if you're reading this - do you think my card might be malfunctioning?)
c. my Samsung SUHD TV, used as a grading monitor: it's said to have maximum brightness of more than 1,000 nits but when highlights occupy to large an area, it turns light grey without details but with lots of compression artifacts (yeah I know - calibrating should be repeated - but could the difficulty with retaining highlight detail & color indicate some hardware problem in my TV?)
Before you guys point at tone of the above as the most probable reason, let me show you the only way I can alleviate the problem with Resolve grading controls:
- Highlights and Shadows.JPG (11.58 KiB) Viewed 2189 times
As you can see, the "Highlight" control must be turned down considerably to protect sky color & details; it doesn't seem to decrease Gain too much (so the overall brightness is not overly reduced), while preventing the abovementioned turning of highlights into one detail- and color-less area. BTW, in this particular example I also elevated the Shadows - but that's because the scene has been back-lit considerably. As can be seen in the screen grab below, the clouds' color and detail has been retained - while the scopes still reach 1,000 nits with their peaks:
- Parade.JPG (41.01 KiB) Viewed 2189 times
And the resulting grade (in its basic stage, ready for fine-tuning) is OK in that the sky is not overblown into detail-less gray while the shadows are not too dark, with details but not noisy:
- SDR screen grab from HDR project.jpg (440.87 KiB) Viewed 2189 times
I need to add that this kind of problem with retaining (otherwise completely legal in HDR10) highlights' detail & color has been increasing lately; this would indicate hardware rather than software problem... Also, in your grading experience much deeper than my own, is a need for such intensive tuning of Shadows and Highlights considered normal - or very rare at all? Your answer to this question would help me tremendously, as at beginning of my using Resolve on this particular hardware I never even touched those controls, whereas dialing the Highlights down has become more and more necessary lately... Looking forward to your suggestions and opinions,
Piotr
Last edited by Piotr Wozniacki on Tue Oct 10, 2017 10:15 am, edited 1 time in total.
AMD TR 2990WX CPU | MSI X399 CARBON AC | 64GB RAM@XMP3200 | 2x RTX 2080Ti GPU | 4x 3TB WD Black RAID0 media drive | 3x 1TB NVMe RAID0 cache drive | SSD SATA system drive | AX1600i PSU | Decklink 12G Extreme | Samsung UHD reference monitor (calibrated)
