In February 2011, I used RGB adjustment effect in order to remove the green cast found on my underwater footage.

The before/after result can be seen here: http://www.kdenlive.org/forum/short-underwater-video

I'm editing a new short movie with 0.7.9 (SVN 5539) but the RGB adjustment simply doesn't work and creates all kind of artifacts. For sanity check I opened my older video files (from February) and tried to apply the same kind of RGB adjustment but again it gave me some pretty weird results. I played with all the sliders and checkboxes but no combination would produce an a realistic result.

Has anything been added or changed to this effect since February? This is really problematic for my project.

Thank you in advance
Alphazo

According to the Frei0r GIT log, nothing was changed in the plugin since I pushed it last August.

I compiled the newest version of Kdenlive (using the new script) a few minutes ago, and RGB color adjustment works fine here.

Sorry, but no idea where your problem might be...

I confirm that there is a problem with 0.7.8-3 and SVN version of kdenlive.

You can try it for yourself with this test project that only contains one picture.
http://natzo.com/testcolor-correction.zip

1) Kdenlive 0.7.8-2 (Jan 2011) + mlt 0.6.0-1
- Load the project
- Select the clip in the timeline and change the RGB adjustments (keep contrast, adjust gamma)
- When you move slider from 0 to 1000 on any channel, you will see the color cast changing without any artifcat. You can finely adjust green and blue cast in a linear way.
- On this specific underwater picture you can put green and blue slider close to zero and red in the high values to get a more realistic picture

2) Kdenlive 0.7.8-3 + mlt 0.7.0-3 and Kdenlive SVN 5539 + mlt git (also tried with mlt 0.7.0-3)
- Load the project
- Select the clip in the timeline and change the RGB adjustments (keep contrast, adjust gamma)
- Trying to move any one of the R, G or B from 0 to 999. No change can be seen on the picture except the same weird colors (solarized).
- Now if you put the R slider to 1000 (and only this value) then the the Green and Blue casts are gone but not precise adjustment can be made.

Again, even if the video filter hasn't changed for a while I strongly believe there is a problem with the way sliders are treated under 0.7.8.3 and recent SVN versions.

Alphazo

I've downloaded your project and here the RGB effect works fine! I've tried to change all the options.

Ubuntu (Gnome) 10.10
Kdenlive 0.7.9 svn
KDE 4.5.5
libmlt 4

I tried to reproduce this, using the files you provided.

I could not open the "testcolor.kdenlive" project, because it reports missing clips.
But I could import the "screenshot.png" file and played with that.
I wasn't able to reproduce your problem. Also, looking on the RGB-parade display, it seems to work as usual, and I could "level up" the curves in the three channels.

I tried both versions that I have installed, 0.7.8-1.pm.1.1 / MLT 0.6.2-1.pm.1.2 as from Suse/Packman RPM repositories, and latest compiled yesterday 0.7.9 (rev. 5539) / MLT 0.7.1. Both seem to work the same.

I am not a Kdenlive developer, so I can not help you further here...

Maybe if you can post a screenshot of the artifacts/distortion, somebody maight guess what went wrong.

It was late yesterday when I tested that. It appears that the problem comes from mlt-git with kdenlive-svn. When installing kdenlive-svn under Archlinux it requires to compile latest mlt from git. This is where the problem shows up with the sliders. Now if I force mlt to version 0.7.0-3 then I can use RGB color adjust under kdenlive-svn.

Sorry for the confusion.
Alphazo

As far as I know there were no relevant changes in the frei0r module since the MLT 0.7 release.
Do other effects work? For example SOP/Sat (which should by the way also be capable of removing the color cast)?