Wicus Labuschagne wrote:Anders Holck Petersen wrote:Hi Anders, this is very interesting and I'd like to test this. Your "Full Res Resolve, Sharper Filter" looks better than your "Full Res ARRI" export.
Hi Wicus.
Yes, the built in Resolve 12 GPU "sharper" debayer differs from the ARRI ADA-5, (the latest ARRI debayer used in ARC and the ARRI CPU mode in Resolve. Lets not discuss "smoother" Resolve debayer, only the "sharper" version)
There are a lot of subtle differences when comparing the two. To my eye some image details looks better using ADA-5, some looks better with the Resolve de-bayer (not nescesarily sharper, but also more pleasing, less noise, better highlights, less artifacts, less moire )
If you look closely at the images of the red chinese lamp I attached, you will see that on the ARRI ADA-5 image, the upper part of the lamp shows more detail, but less detail is shown in the lower part.
In the Resolve debayer it's the oppesite. Softer in the saturated red upper part, but more detail in the bottom part.
Also the contour of the lamp looks less aliased in the ADA-5 image, but the boke of the bright bulbs far right looks more aliased in the ADA-5 image.
Differences like this are seen in all images. Some parts are better handleded by the Resolve debayer, some are better handled by ADA-5. I think they both look really good, so I wouldn't hesitate to use either if it makes the workflow more fluid. As I said before, the feature we are currently doing was first consolidated in the resolve media manager to new RAW files with handles, then batch converted in ARC using ADA-5 on a renderfarm. Im my tests the ADA-5 algorithm suited this productions saturated anamorphic images better than the resolve GPU debayer.
For all practical purposes, doing real time grading from the RAW files, is not always useful. Especially with the transition to 4K/UHD, small VFX fixes will probably be needed in almost every shot of any feature with a budget, and in that case Andrew is right: The right option is to conform, convert and then grade. Shuffling RAW and DPX/EXR, converting mid grade etc. is a total nightmare and you dont want to hand over RAW to the VFX department directly. Last time I checked (about a month ago) NUKE 9 was still using ADA-3, which looks different from ADA-5. As a lot of post VFX work takes place prior, or during the grade, "Baking in" the RAW to RGB must happen at some point, and converting everything, can be much better as the RAW controls will disappear in resolve on all VFX shots returned. This can really be bad is you replace a RAW clip with a rendered VFX shot.
What I do like about realtime RAW grading is the ability to tweak the algorithm per scene. It should be no surprise to anyone that the bayer pattern is a compromise, and so is the debayer algorithm. The default settings in the converter is a choice of parameters where most scenes will look good, but none will look it's best. It might be subtle though. Low noise daylight scenes might be great with the sharpest tweak you can get away with, but low light scenes might be better off with a more relaxed processing. Why exaggerate the grain with a sharp debayer, if you de-noise afterwards. and why pull out details in a woman face it you have to spend more time blurring them away afterwards.
I believe the missing ARRI GPU accelerated debayer inside resolve is a question of assigning resources. That it's now possible in resolve 12 to use the latest ARRI debayer is really nice, but of course it's to slow to use in any realtime session. Hopefully the ARRI GPU de-bayer will be implemented later, as it's important to have a common mode across platforms. The Resolve debayer seems perfectly adequate in "sharper", unless you need to match the ADA.
Thu Oct 01, 2015 2:37 pm
