Speed up Slow Down Pixelation

Hello,

I have a client that has submitted a BetaSP of a video that was edited and output from Avid. When I play it back all of the normal speed shots look fine, however all of the sped up or slowed down shots look very pixelated/stairstepy/interlaced. The original editor insists that everything looks OK on his end but when playing back the tape it is very noticeable. As a matter of fact one shot where it is playing back at normal speed and then speeds up, the frame the sped up video starts the logo in the background looks very interlaced. Then when the shot goes back to normal speed every thing is fine. The same goes for any of the slow motion shots.

Oh and this is for a DVD so when I encode these shots look even worse.

Any insight would be very appreciative.

Thanks,

Luke