Proper color correction

Hi everyone !

I've been waiting a long time for a usable video editor to come to Linux, and Kdenlive seems to be by far the best available (combined with Blender for advanced compositing) and I really hope it will continue to improve in all areas.

But to my mind, one effect that would really be essential is an actual color correction effect. With the kdenlive and the frei0r effects you can do a lot (contrast, gamma, hue, saturation and a lot of fairly bizarre color effects) but there is no color correction effect that just allows you to modify the red green and blue values ! Even simple sliders would be enough for basic correction (even though curves would be even better...).

It seems a bit strange to have effects such as equalyz0r, G, B, R or RGB-parade but no simple RGB sliders...

There are a lot of effects or features that would really be useful (I won't list my personnal needs here, it's not the point), but this particular one would really be useful to any filmmaker that care about colors...

Maybe file a wishlist on the bugtracker at http://kdenlive.org/matnis, or upstream (such as at the MLT project prage).

LeHomard wrote:
It seems a bit strange to have effects such as equalyz0r, G, B, R or RGB-parade but no simple RGB sliders...

There are a lot of effects or features that would really be useful (I won't list my personnal needs here, it's not the point), but this particular one would really be useful to any filmmaker that care about colors...

Hi LeHomard

Please post a feature request at http://www.kdenlive.org/mantis with a description of precisely what is missing. Is this something like the "curves" or "levels" in gimp, or is it something else? I am no expert on it, but it seems to me, that color correction can mean different things to different people.

Thanks.

Mads

Request posted. Here's what a sent :

Quote:
There are many color effect in Kdenlive but there is no color balance or advanced color correction available. The desired result can be obtained with a mix of saturation, hue, contrast, luminosity and gamma, but it it's neither user-friendly nor efficient (for one thing all these settings are in different effects making it very tedious to do color correction on many clips).

One really usefull effect would be Color Balance. For an example see The Gimp Color Balance tool : 3 sliders for colors and a choice between Highlights, Midtones and Shadows (not necessary but useful for advanced tweaking). It is simple to use and understand and at the same time fairly powerful. Using the RGB curves would be even better, but probably not as user-friendly for simple tweaking....

Of course having additional sliders in the same effect for contrast, gamma and saturation would be even better and would make it a lot easier to apply similar color corrections to many clips.

Is it worth posting a lot of requests like that ? I've been trying to use Kdenlive for little projects and there a always a lot of things that bother me (apart from the random crashes... but I'm using development version, so they are to be expected).
For instance the transitions that used to be cleanly separated from the clip but that now overlap and make it very difficult to change the volume, the audio fades in/out that I can't resize, the compositing that is a transition when it should rather be an effect (or should actually be something completely different...) etc. Obviously there is still a lot of work to do, and bugs to fix, and I'm not sure I'm really helping by simply complaining... Anyway, I keep on updating my version and checking out new things, because as I've already said, Kdenlive seems to be the last hope for video editing on Linux...

LeHomard wrote:
Request posted. Here's what a sent :

[..]

Is it worth posting a lot of requests like that ? I've been trying to use Kdenlive for little projects and there a always a lot of things that bother me (apart from the random crashes... but I'm using development version, so they are to be expected).
For instance the transitions that used to be cleanly separated from the clip but that now overlap and make it very difficult to change the volume, the audio fades in/out that I can't resize, the compositing that is a transition when it should rather be an effect (or should actually be something completely different...) etc. Obviously there is still a lot of work to do, and bugs to fix, and I'm not sure I'm really helping by simply complaining... Anyway, I keep on updating my version and checking out new things, because as I've already said, Kdenlive seems to be the last hope for video editing on Linux...

Yes, I think it is worth it. If you look at the roadmap (

http://www.kdenlive.org/mantis/roadmap_page.php

), for some of usuability issues that have been reported and fixed since the 0.7 beta release, many of them is a direct result of issues or features posted by various casual users (like you?). I personally think it is a fact of all development that the developers very quickly adjust to the quirks of the interface, and every project needs outside input to iron out these quirks. Which can be pretty weird.

Re the audio fades: you should be able to drag the corners of the fade in/out triangles to adjust the fade time, but take a look at

http://www.kdenlive.org/mantis/view.php?id=258

- which is an example of exactly what you have also just been doing :-)

I think, technically, that composition must have two inputs to get one output. Technically I think it is only available in kdenlive as a transition, although it is perfectly possible to construct the composition in such a way, that the result in no way resembles a transition.

I also think you should complain about the overlap of the effects; state clearly what you consider the problem and what you think would be a viable solution. But, then again, I am strong supporter of tracking issues like that..

Oh right now I see how to resize audio fades... Thanks ;) But even knowing there ws a green spot I was supposed to drag it still took me som time to actually find it... And of course when a fade is during a transition (which it will often be, obviously) that spot isn't isn't clickable because of the overlapping transition... I think I'll post a report about that issue, then.

Oh and I've just noticed that all the frei0r effects (except one : distort0r) have disappeart after recompiling Kdenlive... Weird...

LeHomard wrote:
Oh right now I see how to resize audio fades... Thanks ;) But even knowing there ws a green spot I was supposed to drag it still took me som time to actually find it... And of course when a fade is during a transition (which it will often be, obviously) that spot isn't isn't clickable because of the overlapping transition... I think I'll post a report about that issue, then.

Please note, that issue 258 may already cover this?

LeHomard wrote:
Oh and I've just noticed that all the frei0r effects (except one : distort0r) have disappeart after recompiling Kdenlive... Weird...

Build issue? Or could it be the blacklist?

The blacklist ?

Actually there are two frei0r plugins, box blur and distort0r...

Here is what i get when installing :

hugh@hugh-desktop:~/compil/kdenlive/kdenlive$ sudo make install
[ 94%] Built target kdenlive
[ 96%] Built target kdenlive_render
[ 98%] Built target westleypreview
[100%] Built target pofiles
[101%] Built target pofiles
[101%] Built target pofiles
[102%] Built target pofiles
[103%] Built target pofiles
[104%] Built target pofiles
[105%] Built target pofiles
[106%] Built target pofiles
Install the project...
-- Install configuration: "Debugfull"
-- Up-to-date: /home/hugh/kdenlive/bin/kdenlive
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/kdenliveui.rc
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/kdenlive.notifyrc
-- Up-to-date: /home/hugh/kdenlive/share/config.kcfg/kdenlivesettings.kcfg
-- Up-to-date: /home/hugh/kdenlive/share/applications/kde/kdenlive.desktop
-- Up-to-date: /home/hugh/kdenlive/share/icons/oxygen/scalable/mimetypes/application-x-kdenlive.svgz
-- Up-to-date: /home/hugh/kdenlive/share/icons/oxygen/scalable/mimetypes/video-mlt-playlist.svgz
-- Up-to-date: /home/hugh/kdenlive/share/mime/packages/kdenlive.xml
-- Up-to-date: /home/hugh/kdenlive/share/mime/packages/westley.xml
- /root/.local/share
- /usr/local/share/
- /usr/share/


Note that '/home/hugh/kdenlive/share' is not in the search path
set by the XDG_DATA_HOME and XDG_DATA_DIRS
environment variables, so applications may not
be able to find it until you set them. The
directories currently searched are:


-- Up-to-date: /home/hugh/kdenlive/bin/kdenlive_render
-- Up-to-date: /home/hugh/kdenlive/lib/kde4/westleypreview.so
-- Up-to-date: /home/hugh/kdenlive/share/kde4/services/westleypreview.desktop
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/effects/automask.xml
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/effects/boxblur.xml
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/effects/brightness.xml
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/effects/charcoal.xml
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/effects/chroma_hold.xml
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/effects/chroma.xml
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/effects/freeze.xml
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/effects/gamma.xml
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/effects/greyscale.xml
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/effects/invert.xml
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/effects/ladspa_declipper.xml
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/effects/ladspa_equalizer.xml
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/effects/ladspa_limiter.xml
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/effects/ladspa_phaser.xml
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/effects/ladspa_pitch_scale.xml
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/effects/ladspa_pitch.xml
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/effects/ladspa_rate_scale.xml
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/effects/ladspa_reverb.xml
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/effects/ladspa_room_reverb.xml
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/effects/ladspa_vinyl.xml
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/effects/mirror.xml
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/effects/mute.xml
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/effects/normalise.xml
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/effects/obscure.xml
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/effects/rotation.xml
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/effects/sepia.xml
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/effects/sox_echo.xml
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/effects/sox_flanger.xml
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/effects/sox_pitch.xml
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/effects/sox_reverb.xml
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/effects/sox_vibro.xml
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/effects/threshold.xml
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/effects/volume.xml
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/effects/wave.xml
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/effects/fadein.xml
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/effects/fadeout.xml
[b]-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/effects/frei0r_squareblur.xml
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/effects/frei0r_distort0r.xml[/b]
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/export/profiles.xml
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/icons/hicolor/16x16/actions/./kdenlive-align-vert.png
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/icons/hicolor/16x16/actions/./kdenlive-hide-audio.png
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/icons/hicolor/16x16/actions/./kdenlive-hide-video.png
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/icons/hicolor/16x16/actions/./kdenlive-show-markers.png
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/icons/hicolor/16x16/actions/./kdenlive-insert-rect.png
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/icons/hicolor/16x16/actions/./kdenlive-add-text-clip.png
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/icons/hicolor/16x16/actions/./kdenlive-add-clip.png
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/icons/hicolor/16x16/actions/./kdenlive-show-video.png
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/icons/hicolor/16x16/actions/./kdenlive-snap.png
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/icons/hicolor/16x16/actions/./kdenlive-show-audiothumb.png
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/icons/hicolor/16x16/actions/./kdenlive-show-audio.png
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/icons/hicolor/16x16/actions/./kdenlive-show-videothumb.png
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/icons/hicolor/16x16/actions/./kdenlive-add-color-clip.png
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/icons/hicolor/16x16/actions/./kdenlive-add-slide-clip.png
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/icons/hicolor/16x16/actions/./kdenlive-align-hor.png
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/icons/hicolor/scalable/actions/./kdenlive-zone-end.svgz
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/icons/hicolor/scalable/actions/./kdenlive-select-tool.svgz
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/icons/hicolor/scalable/actions/./kdenlive-zone-start.svgz
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/banner.png
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/timeline_nothumbs.png
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/timeline_athumbs.png
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/timeline_vthumbs.png
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/timeline_avthumbs.png
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/transition.png
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/metadata.properties
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/blacklisted_effects.txt
-- Up-to-date: /home/hugh/kdenlive/share/apps/kdenlive/blacklisted_transitions.txt
-- Up-to-date: /home/hugh/kdenlive/share/locale/ca/LC_MESSAGES/kdenlive.mo
-- Up-to-date: /home/hugh/kdenlive/share/locale/cs/LC_MESSAGES/kdenlive.mo
-- Up-to-date: /home/hugh/kdenlive/share/locale/da/LC_MESSAGES/kdenlive.mo
-- Up-to-date: /home/hugh/kdenlive/share/locale/de/LC_MESSAGES/kdenlive.mo
-- Up-to-date: /home/hugh/kdenlive/share/locale/es/LC_MESSAGES/kdenlive.mo
-- Up-to-date: /home/hugh/kdenlive/share/locale/fr/LC_MESSAGES/kdenlive.mo
-- Up-to-date: /home/hugh/kdenlive/share/locale/nl/LC_MESSAGES/kdenlive.mo
-- Up-to-date: /home/hugh/kdenlive/share/locale/zh/LC_MESSAGES/kdenlive.mo

I'm going to try and write a Shadows & Highlight effect (like Shadows & Highlight in Photoshop), Unsharp Mask (for sharpening I guess.. but I use it for local contrast enhancement - large pixel radius, small % amount), and a few colour grading effects.

From now on, you should be shooting camera's in camera colour bars on every tape you shoot (if you shoot tape), and also a colour chart or at least 18% grey card or some white card (the same white card for every shot though) for every take, that can help you match correct minor exposure differences and white balance differences.

 Hi
 
There are two things mentioned here I think. Primary colour correction to bring various clips colour to a more uniform appearance and then Secondary colour correction/grading for effect like every feature film you care to mention. Extreme examples like 300. This feature is essential if you intend kdenlive being used or adopted by anyone other than hobbyist who just want to put their holiday/event videos on DVD and don't understand the real benefit colour grading can bring, to the right footage of coarse. ;-). Indie film makers / DV Rebel style it's essential.
 
Colorista is the best source of inspiration for this.
 
Also i think the colour correction and then colour grading would be done with layers on top of the source material not applying to the underlying video so as not to require rerendering the affected sequnece everytime an adjustment is made to see it's effect and so that you can have a history and go back to any point to tweak without rerendering a sequence.

Vegas Studio also uses a 3-way color corrector (like colorista I believe), and I must admit it is really easy to use and understand and tremendously powerful. I don't know of any open source alternatives that use such a system, though.

We welcome any of your contribution. Look around MLT, Gimp effects, Frei0r effects, maybe Digikam and contact the main Kdenlive hackers. A cool place to start would be the developer mailing list: http://www.kdenlive.org/developer-mailing-list

Color correction is a must-have tool for anyone that want to get their video to look better. It can take an average looking video and lift it to the "great" level. On the other hand, if the user do not know what s/he is doing, it can totally ruin the video.

As well as having the right tools, color correction is all about using the right workflow. And the tools that are developed needs to promote that workflow.

Do a google search for avid color correction and you should get several very useful links. The first hit I got was to a pdf that is actually the course manual for a course I am teaching. Grab it and read it. There is a lot of good information and examples of a very nice interface :-) there. http://www.fmctraining.com/conferencenotes/AvidCC.pdf

Before anyone even think about doing any effects at all on a video, they need to have a tool that show what they are doing. You can NOT trust your screen. You can NOT trust your eyes. The only objective thing you have is a video scope.

Also, you really need to have three side-by-side monitors/viewers so you can compare clips. As I said, you can not trust your eyes, but you can make comparisons and realise one has more blue than the other etc.

Another important thing is to realise that video is not photo. So never think of Kdenlive as Gimp with video. It does not work. Video has totally different demands and needs to be understood and treated that way. One very important thing is something called legal colors.

There are rules to how light or dark colors can be in video. All equipment is made to this specification, so it is important that you know about it when you do cc and that the tools you have can warn you if you step outside those boundaries.

I am not quite sure where to stop... I have a lot on my mind regarding this and would love to see Kdenlive get a proper cc module. As some others here have mentioned, I believe Kdenlive is the best video editing application in Linux and it is the only hope for anyone that want to do anything serious in this area.

Not intended as sarcasm - how important are the legal color restraints when all you do is publish your videos online or play them back on a home media center with a digital panel of some sort (not via optical disc)?

Is youtube publishing Kdenlives target market?
I thought it aimed to be a fully fledged video editor, capable of any sort of output?

Uh, I prefaced that as "not intended as sarcasm" and you you still took it completely the wrong way. Yes, kdenlive is for general purpose, but clearly the trends are for Internet distribution (streaming and download) and non-optical in-home playback, and I believe the majority of kdenlive users fall into these categories. This is where my priority is as the MLT developer.

With that said, MLT was originally written for television broadcast applications, and it does constrain the Y'PbPr gamut to the legal limits. Also, it does scaling conversions to and from RGB. IOW, you produce RGB-based assets using the full range of RGB values and let MLT handle the conversion to Y'PbPr and worry about the legal limits but not by simple truncation of the extremes of the gamut but through scaling by differences in the ranges of each gamut.

Your comment about not sarcasm made me take your note dead serious. As in "no need for colour correction here".
That's how blunt tool for nuances forum posts can be.
(sorry for being a bit OT)

It is my understanding that Dan does indeed think that color correction is needed. He wrote the white balance plugin for Frei0r, after all, and the color correction tool for kino.

I think he just talks about a specific set of rules, in relation to color representation in a specific format?

>Not intended as sarcasm - how important are the legal color restraints when all you do is publish your videos online or play them >back on a home media center with a digital panel of some sort (not via optical disc)?

It is VERY important. As somebody else mentioned, I guess you want to cater to all varieties of production, and you never know what kind of equipment your production will end up on (usually). As soon as someone puts it out on a TV, and there are a number of ways to do that, even with a media center, the legal color game is into play. As I said - all the rest of the tools in the chain are tuned to this and actually expect others to do the same. The problems occur when one link in the chain does not want to play ball. What usually happens is that this link is excluded from the chain :-) You would be amazed at how many that still watch moving pictures on tv screens.

For a free tool like Kdenlive, this is actually even more important. It is more likely to be used in poor areas of the world, and I can tell you this - in the village here in the mountains of Brazil where I live now, it is really far between the media centers. But almost everyone has a TV or two, and most of them have DVD players. And yes, even in the slums here in Brazil, a lot of people have computers and internet. So if you forget for a second about USA and Europe where people can afford to buy one of the major videoediting systems, I think you will see that in the major market for Kdenlive, DVD and TV is still king :-)

Try using the Technicolor Effect