So what sound would be coming out with PDVD 7?
What sound is coming out from PDVD 8?
The same, 5.1 channels in not higher than 16bit/48kHz.
They differ in how, what soundtracks and with what hardware the sound is bitstreamed...
And I think PDVD8 doesn't do HD DVDs.
My receiver is fairly old.....is there anything it needs to be able to do other than have the 6 CH input?
Are there some shortfalls with using the 6Ch out compared to SPDIF?
This question is a can of worms...
Audiophiles will tell you PC's DACs (Digital-Audio Convertors) are inferior to the DACs in AVRs.
Those with $10K+ in audio equipment will claim the jitter is unacceptable... Stuff like that.
Analog outs have one advantage: it is the only way to properly mix the soundtrack with other sounds, like menu, PIP sound...
I'd recommend both, the HTPC and AVR, to be connected to the same power bar, i.e. having a common ground (to avoid humming).
Also, make it a rule to turn the AVR on after
the PC is turned on - or you most likely will hear a unpleasant pop from your speakers...