Does BSPlayer use an own Source Filter? slow MP4 seeking

[bond]

lo bst

i noticed slow seeking in bsplayer with long .mp4 files. especially if i try to jump from the beginning to the end, it seems as if bsplayer analyses the whole file before playing the end part, which takes some time
i call it analysing because if i jump back to the beginning and than again back to the end, its fast (like bsplayer first has to analyse the parts to jump to, before seeking is fast)

when i play the same file in another dshow player or graphedit (with the 3ivx splitter filter) the seeking takes is fast right from the beginning, therefore i somehow wondered whether bsplayer uses an own source filter or so, which slows down the process compared to the default dshow source filter (async)?

thanks :)