I actually don't think non-available resolutions would make post processing impossible. But it depends on two options:

- are you running in window mode ?
************* or *********************
- are you running in fullscreen mode ?

Just to make it clear, there is is difference in use with video_set. In window mode, arbitrary video resolutions are supported as long as they fit on the desktop screen and sufficient video memory is available. For full screen mode, only a few video resolutions are supported, dependent on the 3D card.

Further more there is one other aspect, I think trying it via video_switch is a better option because it supports up to 1920x1200 but then again you can't allowing arbitrary video resolutions like in video_set.For now, try setting it through video_switch, it seems the best option to work around the limited resolution reach from video_mode but a clear disadvantages is that you're bound to is the number that determines the screen resolution which is anti-arbitrary

Hope that helps, if not then I'm completly wrong And you should ask other users who already have had experience with Sylex3 like Guitar.

Cheers

Frazzle