QPEL: Do previous & current dev-builds make good but buggy non-standard encodes?

I have made different encodes using motion search 6 (qpel) with 11/10, 12/10, 13/10 and 21/10 CVS dev-builds, they look from pretty good to excellent in playback... but only when ran with XviD compiles of the respective date! (otherwise starts to appear hell of smearing artifacts) I well know these are *unstable* builds, but what's strange is that motion/quality is near to perfect when I play them with "respective" encoder date/version... when I use more recent builds to decode previous created (qpel) AVIs I see smearing artifact appearing. Are these all bugged non-standard MPEG4 videos? :scared: "If the binaries are bugged" why does encoding and decoding using the same CVS version give very good results? (no smearing surprises) I have several clips that encoded and gone perfectly with quality, but now decoded with 21/10 and 22/10 builds they looks orrible! (smear everywhere) This happens with o without DirectShow... so even with VirtuaDub session.

That is the impression I got from the developers (just reading posts), B frames are in final form (current encodes with B frames should be playable in the future) and Qpel is not - encodes made with Qpel may be/are incompatible with future builds of Xvid. Hopefully qpel will become finalized soon so I can start making archival encodes with qpel on (Or I could just burn the xvid I encoded with to every cd of encoded material - if it won't play with future versions of xvid just install the one it was encoded with ;) ).

I used DX50 fourcc for all recent Xvid encodes and i don't appear to be experiencing any problems at all, even with q-pel...am i missing something?