Incorrect audio-sync was a known issue back in the early days of MPEG4 encoding.
Getting it right was very, very hard, and some tools even came with options to "tweak" the output-stream to get things synched up, specifically tailored for the behaviour of the Frauenhofer MP3 decoder.
I suspect some videos encoded using these tools may render and synch "incorrectly" on newer players not aware of the workaround done in the past to make improper codecs behave properly, even though they may be 100% within spec.
I'm guessing the DivX-player (which sounds like a very stuck in the past kind of thing) uses old codecs and are able to account for this, by not following spec while rendering these "tweaked" video-files.
Getting it right was very, very hard, and some tools even came with options to "tweak" the output-stream to get things synched up, specifically tailored for the behaviour of the Frauenhofer MP3 decoder.
I suspect some videos encoded using these tools may render and synch "incorrectly" on newer players not aware of the workaround done in the past to make improper codecs behave properly, even though they may be 100% within spec.
I'm guessing the DivX-player (which sounds like a very stuck in the past kind of thing) uses old codecs and are able to account for this, by not following spec while rendering these "tweaked" video-files.