Thanks for your right choice!
Smoothness of HD playback basically depends on the decoders performance
and additionaly on the right demuxer implementation. The last thing here is the application implementation.
AC3 decoding limited by Dolby license restrictions. So as it mentioned at our site here:http://www.elecard.com/products/products-pc/consumer/dvd-player/
we can only redirect AC3 audio to HW SPDIF output.
sytem license for dual channel AC3 decoder. 5.1 licensing is in progress. So soon you will be able to get such decoder as a developer.