Hi,

I'm currently editing a 1080p video. Everytime I apply a more sophisticated effect to a clip (e.g. Glow oder Nervous) or add an overlapping transition between clips, playback in the project monitor gets really choppy/laggy... very bad overall.

I'm not expecting a stellar performance from my pretty-old-but-not-THAT-old rig (2 x 2.9Ghz, 4GB RAM, GTS450, Linux Mint 13 x64) and I'm not blaming kdenlive for not performing as well as Premiere (or other expensive commercial video editing suits) - but nevertheless I wonder if there are any ways to improve performance.

So, Questions:

- Is this poor performance to be expected? What is considered "normal" performance?
- Is there a way to "dumb down" the video preview? I don't need HD in the project monitor playback window.

You may want to use proxy clips for your footage. You can configure them in your project settings. Proxy clips are a low resolution "copy" of your original footage.

right click in the monitor and check Real time (drop frames)

Setting this to the Checked state means the clip monitor will drop frames durring playback to ensure the clip plays in real time. This does not effect the final rendered file - it just effect how the clip appears when being previewed in the clip monitor

http://userbase.kde.org/Kdenlive/Manual/Monitors/Clip_Monitor_RightClick

Sooo... I created a proxy clip. Surprisingly, while now very low quality, the performance of the preview clip didn't improve by the slightest bit :(.

How did you create the proxy and what codec / resolution. You can create custom proxy profiles to suit hardware ability for any project. Have you tried various proxy profiles?