I am working now with video digitizing and compression (Sequence
Grabber API). When recording a movie, the movie will only be recorded
in the size that was set by SGSetChannelBounds (the preview size). I
need to record in one size, while the preview will be in a different
(usually bigger) size. Is there a simple way, to preview and record in
different sizes? I tried to use SGSetCompressBuffer but this didn't
work (the resulting movie was blank white...).

Any idea? I suppose this can be done with callbacks but I wondered if
there's a simple way to do it before I dive into the callback stuff.