With a DVD player, when using the DVI output for video coupled with coax/optical digital for audio, am I correct in assuming that there are no processing being done by the DVD player?.
If this is the case and assuming that one does have a decent AV amp for the processing of audio and video processing being done by the projector / tv, why would one need an upmarket DVD player?.

[MarkE19]

There is still some processing being done by the DVD player. The data on the disk, although still in a digital format all the way to the receiver & screen still needs to be decoded from MPEG-2.
You then have interference that can be easily picked up if the components are not well designed and isolated.
The player will need to do error correction when reading the disk

etc, etc.

Mark.