9.0b no problem.
open the mp4 file in quicktime or mediaplayer,
use mouse to fast seek the playback position, VERY SLOW...
index frame problem?
but not index frame setting...
the mainconcept build shows build 6196
Don't have an answer but wanted to acknowledge that I have the same issue on my Vista laptop. The Sony rendering seeks fine. The MainConcept rendering takes what feels like forever and is unusable.