A Simple Question: DVD & Pre-Pro


I'm almost embarrassed to ask this question...

For the processing of Dolby Digital and DTS, is it necessary for both the DVD Player and the Pre-Pro to have the associated decoders?

Or, is it that the DVD player need only pass the 5.1 PCM stream to the DD & DTS decoders within the Pre-Pro?

I want to buy my daughter a DVD player, but am unsure whether I need to buy a pre-pro, as well, to hear the DD & DTS sound (I do know the differences between DD & DTS).

If I'm not asking the correct question, and you can figure
what the right question is, I would appreciate your help.

Thanks.
mdorsam
You only need one decoder. Most people pass the digital signal to the prepro. The one in the receiver/prepro typically has more features, flexibility with bass management, and perhaps higher quality.
The DVD player also need to be able to do it. My DVD player will play dolby digital but not dts.
You need DTS on the DVD player and the pre/pro if you wish to view movies in DTS