About linear color space

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Asusgl112
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About linear color space

#1

Post by Asusgl112 » Thu Jun 14, 2018 8:56 am

Hello,everyone, I use gh5s to shoot vlog footage how to transform into the linear color space in the fusion?

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Re: About linear color space

#2

Post by SecondMan » Thu Jun 14, 2018 9:32 am

With a little googling seems there is a LUT available here that transforms from V-Log to Rec709. From there you could go to a linear colourspace. Or there may be others available. Check with Panasonic support I'd say.

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Re: About linear color space

#3

Post by Midgardsormr » Thu Jun 14, 2018 11:24 am

There's no LUT that goes the other direction, though (as far as I know), so once you're in 709/linear, there's no way to get it back to log again.

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Re: About linear color space

#4

Post by rslittle » Thu Jun 14, 2018 12:43 pm

Ouch to go log to 709 to linear if the 709 lut clamps. It would defeat the whole point of shooting in vlog. So if you try this make sure the lut isn't clamping when you go to 709.

There is an ACES vlog to linear lut. but its part of this opencolorio config. You can download it. Then make an opencolorio colorspace node and you will see load config. Do that :-)

https://github.com/imageworks/OpenColor ... nasonic.py


SecondMan wrote:
Thu Jun 14, 2018 9:32 am
With a little googling seems there is a LUT available here that transforms from V-Log to Rec709. From there you could go to a linear colourspace. Or there may be others available. Check with Panasonic support I'd say.

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Re: About linear color space

#5

Post by Midgardsormr » Thu Jun 14, 2018 1:18 pm

I don't think the VLog to 709 LUT clamps, at least not anywhere below a useful white point; I tested it a few weeks ago for someone. They ultimately decided to use the Josh Pines conversion in a CineonLog tool, though, because it gave a visually pleasing result and they wanted to reduce the opportunity for errors in the color handling.

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Re: About linear color space

#6

Post by intelligent machine » Thu Jun 14, 2018 2:28 pm

Here's the reference doc I found with the math for the V-Log to linear conversion. I haven't taken a close look at it but did see a set of color matrices that can be used in the Gamut tool while set to custom. I was looking at the CineanLog tool and see an input for "conversion table" under log type "Cineon". What does a conversion table look like?

https://pro-av.panasonic.net/en/varicam ... -Gamut.pdf

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Re: About linear color space

#7

Post by Kaleb » Fri Jun 15, 2018 10:10 am

Hi, does converting the color space and then rendering the output loss video quality?

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Re: About linear color space

#8

Post by SecondMan » Fri Jun 15, 2018 10:22 am

It doesn't have to. It totally depends on how you are converting the colourspace and what your output is rendered as.

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Re: About linear color space

#9

Post by Midgardsormr » Fri Jun 15, 2018 10:29 am

I should amend what I said earlier. I wasn't referring to mathematical error, but human error. It's twice as easy to make a mistake when you're using twice as many tools. ;)