http://www.fraps.com/

1) cl_avidemo "x"

- capturing tga's into screenshot directory.

x - number of fps. Minimal is 25 fps, if more then smoother video.

2) VirtualDub (http://virtualdub.sourceforge.net/)

- From tga's to avi.

note. You can choose how much fps you want to render.

If you captured demo at 25 fps - recommending output avi at 25 too. (25 fps is minimal)
If you captured demo at 200 fps - for additional editing you can choose from same source (200 fps) or 100 fps.

In first demo (timescale1) you used standard timescale 1 - so it is default for q3. There souldnt be problem if u used same fps (check again). I noticed video is in 25.00 fps but you didnt write how much fps u captured screenshots.

In second u used timescale 0.3 so u captured more fps in time like in your previous one (timescale1.mp4) video. It isnt laggy, they are just more FPS thats why it is going slower.

Cant get why u used timescale as well, if you want smoother video, set avidemo to higher value, not lowering timescale.

From Vdub u got mp4 format ?

When u explain me why u used timescale and how you got mp4 format from Vdub i will tell you exactly where u made mistake. I know it already Doc but wanna know find point in it