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Old 17th October 2009, 15:00   #10142  |  Link
mark0077
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Join Date: Apr 2008
Posts: 1,106
Yep those 5.1 tests arn't played correctly on Xonar HDAV Deluxe, as I already said, mpc and ffdshow explicitly output to back, not sides...... I challenge anyone to find a soundcard that will make mpc-hc or ffdshow explicitly output to sides (or anything other than back even), which would show at least that mpc doesnt just blindly output to back all the time, that it smartly detects where to send surround output based on what the sound cards drivers want.

I havn't seen anyone yet that can show mpc-hc or ffdshow visually outputting to the sides. They always choose back by default as far as I can see, this is where the problem lies. Again this is fine if your soundcard remaps the back to the sides, but unfortunately not all soundcards will do this, some will "smartly" upmix these back channels to sides if sides is where surround exists, and this upmixing isn't as nice as pure channel remaps in this weird situation.

So 5.1 tests you give above fail in cards with this upmixing ability, ie those that don't just do a channel remap like your soundcard. These tests will show this upmixing function of these soundcards (what sounds like left bleeding into right channel and vice versa), rather than whats intended, pure channels being sent to the right place in the first place.

EDIT: Looking at the link you provided (given below) regarding asking the os / driver is a mode supported, maybe mpc-hc is asking the driver first is 5.1 supported using "Back", and of course in a 7.1 soundcard, that mode is always going to be supported, regardless of whether the user or drivers intend the sides or back to be used in a 5.1 config. Read Mikes last entry in the following page. My guess is your soundcard might be saying this mode isn't supported and mpc-hc is therefore choosing side internally but not on its gui, OR your soundcard is saying this mode is supported and mapping channels to side itself.
http://www.freelists.org/post/wdmaud...ode-question,7

Looking at the following pin config document, scrolling down to the 5.1 section, you can see the two different configurations that are possible, obviously one using side (Sequence: (0,1,4)), one using back output (Sequence: (0,1,2)). Still unsure how mpc decides to choose back versus sides. Any devs wanna enlighten us
http://www.microsoft.com/whdc/device...PinConfig.mspx

I am obviously just guessing, as I havn't heard from any of the mpc developers on this.

Last edited by mark0077; 17th October 2009 at 16:10.
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