jazzyjayt,
I'll try to answer your question. Your DVD player can either:
1. play DTS, without built in decoder
2. play DTS, with built in decoder
3. not play DTS at all
kung number 1, then you need an AV Receiver that can decode DTS, that way, you can listen to DTS mixes in your DVDs.
kung number 2, (I'm not so sure here) but I think you can connect your DVD player to your receiver (kahit wala siyang DTS capability - but has to be through the analog ins I think), then you can listen to DTS mixes in your DVDs.
kung number 3, you can't listen to DTS at all, but in most cases, may Dolby Digital 5.1 ang mga DVD players, so you can still experience 5.1 sound