Subject: [linux-audio-dev] Surround panning algorithm
From: Greg Lee (greg_AT_ling.lll.hawaii.edu)
Date: Wed Jun 16 2004 - 03:30:43 EEST
I need to do surround panning for a couple of applications.
The following is what I have so far. it's not principled
or analytical --- I just made it up this morning off the
cuff. I'm hoping some of you will have suggestions. Pointers
to sample code for better versions would be nice.
/*
* "pan" is midi pan, 0 (left) to 127 (right)
* "speaker" is 0 (left surround), 32 (left front),
* 64 (center), 95 (right front), 128 (right surround)
* "separation" is 95 for 4-channel surround (left
* front and right front taper down to 0 amplitude
* at right pan=127 and left pan=0, respectively).
* and is 64 for 6-channel surround (center tapers
* down to 0 amplitude at left and right).
*
* Returns amplitude 0-127 for requested speaker.
*/
static int panf(int pan, int speaker, int separation)
{
int val;
val = abs(pan - speaker);
val = (val * 127) / separation;
val = 127 - val;
if (val < 0) return 0;
if (val > 127) return 127;
return val;
}
Greg
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