I have looked a lot around from a decent screencast-application, that didnt make laggy sound or video – without any luck.
The only thing I found that actually worked was FFMPEG (compiled with x11grap). It is kind of annoying to enter these long commands in the prompt though, so I decided to write a small guy application for FFMPEG.
It works be simply placing a window in the area, that you want to record and then press “Record”. You can also select filename and a folder where you want the video to be saved. It will show FPS, length and size for the video while recording.