SPDIF Audio Drop

I'm watching movies using Media Player Classic and when i watch movies encoded with AC3 i get audio drops every 20-30 seconds. When i watch movies encoded in PCM it works fine. The only way i can think of is set Media Player Classic to output to speakers instead of SPDIF Passthrough and let Callisto upmix it to Dolby Digital. But if the movie is already encoded digitally why encode it to analog and then let Callisto encode it back to digital? Can you think of a way to resolve this issue without losing sound quality?

Hi, Do you get the same

Hi,
Do you get the same problem using any other media players? Do you have any 3rd party audio codecs installed?

It's the same even with

It's the same even with Windows Media Player 11.

Which version of the driver

Which version of the driver are you using?

i'm using the latest version

i'm using the latest version from the website

Have you tried earlier

Have you tried earlier drivers? Different DVDs?

Also, do you have 3rd party codecs installed on the system?