Snake oil according to me.
Generally speaking a blu ray or DVD player has optical/coaxial/HDMI outs which are used for audio. So it should all be the same unless you are using some good players like:
1) Oppo DVD/Blu ray players as they are audiophile players built into one chasis.
2) Pioneer BDP-51FD analogue outs which is fed by it's own separate DAC (I have this player so I know it makes a difference)
3) Panasonic DMP-BDT500 which has also got audiophile DACs built in
4) Marantz UD9005 does something similar
5) Pioneer BDP-F9D one of their top of the line players unbelievable build quality
There are many more I am sure but these I got at the top of my head. It is also important that the rest of the components should be up to it, otherwise it makes no difference if you buy a run of the mill or a top end player.