You're right, I'd never noticed before but I've got the same result with previous builds 492 and 490, DivX5 and DivX3 movies, DivX5.02, DivX5.03 and some other DS decoders out of DivX.
But works with MPEG1 and MPEG2 movies.
If you want to know the bitrate of your AVI I warmly suggest you
AviCodec currently in v1.08 at
http://avicodec.duby.info
PS:
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