I would like the LUT (3D) filter to have the ability to select a folder with LUT files and already in the shotcut I could select the appropriate loot in the form of a convenient list, and not click on the “open” button every time, constantly look for a directory with LUTs files and select a new one . I have quite a lot of LUT files and often have to choose between them, and the way it is implemented now is very inconvenient. Thank you.
1 Like
I second that!
A setting to assign a default LUTs folder would be super convenient and time saving.
2 Likes
@dimadjdocent
I read your post again and I see now that I didn’t quite understood your suggestion.
So in brief, I think that what you propose is something like this?
-
A way to select all the folders containing LUTs files. Like in my Mixxx app for example. I can add all the folders containing the music files I want to include in my songs Library.
-
All the LUT files from those folders would then be available to select in a drop down menu or in a list (Like the filters list in the filters panel, maybe).
In Mixxx, that would be the Library panel.
My english = google translator)))
Something like this I would like to see this filter.
Yes, this is essentially the choice of a directory with luts. But since shotcut’s philosophy is not to have a global settings window, adding more directories to the filter itself, instead of selecting one single lut file, would be a great idea.
Your English translation wasn’t the reason why I misread your post. I simply just read it too fast. So it was all my fault 
English isn’t my native language either.
The one for uncle google verification
This is supposedly the best translator.
1 Like
I mainly use DeepL when I’m too lazy to write something myself in English. I love that when you click on one of the words in the translated side, it propose a lot of alternatives. But sometimes I find that the general translations doesn’t sound right. So I switch to Google Translate to get a second opinion and quite often the result sounds better.
Also, lately I’ve noticed that popups are becoming more and more frequent on DeepL.
How would you do it though?
You could list the files, but as LUTs operate on R’G’B’ and video files store Y’CbCr, then you need to get the input and output conversion matrices correct. That depends on the colour space and nominal range.
You could assume that the input and output is BT.709, but then some of the LUTs won’t work.
FFmpeg adds auto-scalers in the filter graph to get from YCbCr to RGB and back, and then LUT processing by nature is done in linear space, not a BT.x gamma space. So it ends up working fine for any color space.
I do see what you mean about a user taking a LUT designed to work within BT.2020 color space and applying it to BT.709 footage, and getting out of gamut colors. Yes, it would be the responsibility of the user to get LUTs designed for BT.709 output.
Not sure you can just do it for the output though. Say you have camera footage shot in V-Log on a GH5 or SLog2 on an RX100 and have a LUT for importing. You’d then need a filter graph:
Y’CbCr-R’G’B’(BT.2020) : LUT : R’G’B’-Y’CbCr(BT.709) or
Y’CbCr-R’G’B’(BT.2020) : Matrix(2020-709): LUT : R’G’B’-Y’CbCr(BT.709)
Many LUTs are “look” LUTs and only work in one colourspace, but some are mathematical conversions between two.
I’m not sure that most of those who use LUTs have thought much about the intricacies of how these LUTs work. For me personally, this is a banal and simple way to color images, giving it some kind of eye-pleasing shade, and in most cases I personally don’t think about whether the transformations are happening there correctly or not, I just look with my eyes - I’m satisfied with the result, or I’ll choose another LUT file out of dozens available. And I thought about loading the “list” of these LUT files into the filter and sorting through it, seeing the result right away, for sure this is implemented in other graphic editors. And I would love to see that in a shotcut sometime in the future.
1 Like
@dimadjdocent Di you try @Elusien’s LUT / 3D Viewer
It’s a web app he created. I know it’s not what you propose, but it’s damn useful when you can’t decide what LUT to use.
I like to reduce the width of the browser window, so the LUT results are stacked on top of each other. It makes it easier to compare each result with the original on the left. And you can import as many LUTs as you want from a single folder.
1 Like
Sorry for my lack of clarity. I used the phrase “designed for BT.709 output” to avoid putting a specification on the input, implying that a color space conversion LUT may be used which has a non-BT.709 input.
I was thinking more of “pseudo color spaces within 709” when I said that, but it would apply to 2020-to-709 just as much. I was thinking more like GoPro Flat or Panasonic Cinelike V or HLG being shifted into higher contrast 709, meaning the input wasn’t normal 709 even when the color primaries are the same.
I think we’re on the same page that it would be up to the user to organize their LUT collection in a way that conforms to the color spaces they are using.