Hi, I'm trying to use the levels effect on my project, but I'm hitting a strange problem. When preview is paused, the video frame looks good and I've used it with levels to adjust everything. But when playback starts the project preview is much darker. I have much snow on the background and the effect is like an additional UV filter. Also the rendered output is in that darker mode than what the single frame preview looked like.

Is this a bug or some feature in X, GPU, Qt or kdenlive?

I'm using Debian unstable and locally compiled ffmpeg, mlt and kdenlive. Machine is a T60 Thinkpad with Intel Corporation Mobile 945GM/GMS/GME, 943/940GML Express Integrated Graphics Controller rev 3 GPU if that makes some difference.

Not that it's much help but I see that too the playback levels change. I'm using Ubuntu 64bit + NVidia 210GT

Have you tried rendering the project without the levels and compared it to the original side by side in the same player?

Does the clip window and project window look the same?

Are you comparing Kdenlive preview with separate media player as it could be that your external player is handling you video differently.

The two problems may not be related. The difference in brightness between playback and clip in Kdenlive may not be connected with darker playback in external to Kdenlive media player.

Could be Kdenlive squashes and expands the levels between edit and playback.

What is the source? What camera?

I use mostly mplayer to view clips but kdenlive uses melt to show the project preview, I presume.

The brightness difference is in rendered clips when played with any player and in the melt previews within kdenlive. I leveled all clips in the project and noticed the difference in the end, so it's a bit hard to disable all of the level effects.

Sources don't really matter but my cameras are GoPro HD helmet camera and Panasonic FZ28 in this project. The result is here:

http://mcfrisk.kapsi.fi/skiing/posts/Sunday.html

When paused the SDL plugin used for the preview monitor switches to RGB mode and when playing switches to YCbCr. It switches to RGB mainly to get off of the XVideo port so you can use it with another application. Also, it used to be that screen shots/recordings of something using XVideo would not show the video. I think that is mainly no longer the case except perhaps it depends on the X11 driver. I will consider changing that behaviour, but I am nervous that I do not fully understand the potential impact. Maybe for this important of an application we should not be so concerned with being system friendly.

Just my 2 cents worth, but Kdenlive's system-friendliness, compared with other NLEs, is one of the things I really love about it.

In a typical editing session, I might have open, as well as kdenlive:
- Writer with script and clip information
- Gimp for creating titles and graphics
- SMPlayer so that I can render sections as I go and play them back full-screen
- Chrome in case I get stuck and need to look something up
- Vinagre to check on the server
- Dolphin because it's always open
- KPatience for when I need a break

Perhaps I'm atypical in my usage, but I think the design philosophy of kdenlive is excellent, and one I hope that you, and other devs, stick to if at all possible.