More than happy that it works for you and your needs and we are probably talking about different things.
The original Pirates of the Caribbean films or the first couple of Harry Potters, all on Blu ray have 5.1 LPCM options as well as Dolby 5.1. Normally I have the PC set to Stereo for CDs and the like, and can play and up mix those with no problems at all, like yourself.
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Try that with those mentioned blurays and it is just stereo.
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Change it to actually match the 7.1 base layer speakers and the rear surrounds will be silent. To get it to work correctly I need to configure the PC to 5.1 just for those discs. If I left it that way all the stereo content would then have silent channels beyond the 2 or 2.1.
It is a stupid problem.
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Why can't the receiver see there are silent channels and ignore them, why can't the PC simply accept 8 channels by default and reconfigure the output on the fly based off the stream? As it is it auto switches between bitstream or PCM and renegotiates the handshake prior to playback anyway.
I'm the other way, I much prefer the Xbox controller over the PlayStation, but I'll still take keyboard and mouse over either for anything other than perhaps driving games.