the .1 in the 5.1 is the sub. You don\'t "have" to have a subwoofer, it\'s just better.
Does your stereo have 6 inputs for seperate channels?
The DVD players with decoders in them have seperate outputs for each speaker. Unless your stereo is built with seperate I/Os for each speaker, you won\'t be able to use the dvd player\'s built in decoder.
If your stereo has a DD decoder in it then you just need a regular DVD player.
Getting a decoder built into the DVD player adds probably 100 bucks to the cost and then you will only here 5.1 with your dvd player. You should get a stereo with the decoder in it so you can get 5.1 with the PS2, your tv, etc....