I believe this is mostly the receiver, but it is also related to the player. Try an analog connection to verify. I tried a few receivers before I found the 8300, which still has the problem, but only in the very rarest of occasion is it even noticable. Most receivers do this with a digital signal. I believe it has to do with the receiver muting the sound while it figures out what that signal is (starting a disc, switching from menu to menu or menu to movie), and some are worse about it than others.
Now, it does have to do with how the player sends the signal too; either breaking the digital stream or the laser on the disc while they skip from point to point on the disc or something. Some players don't cause the receiver to "hiccup", and I haven't found anyone who can tell me why. I've had a number of DVD and CD players and most of them still cause this, but I had a Marantz CC4000 and it never had this problem. It died after just a few months and I didn't bother replacing it with another one.