SQ decoding in Windows Media Player


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Well-known Member
Mar 12, 2005
Sheffield, UK
Randomly discovered this simple way to decode SQ files last night...
I use a program called AC3 Filter to decode .ac3 files or ac3 streams in things like DivXs. However it also supports PCM and has a full 6 channel input > 6 channel output matrix option. By telling it you have 4.0 (or more) speakers then setting the matrix to:
1 Left In > Left Front Out
1 Right In > Right Front Out
0.707 Left In - 0.707 Right In > Right Rear Out
0.707 Right In - 0.707 Left In > Left Rear Out
you have a handy on-the-fly passive SQ decoder. Tested this with an SQ sample of Pink Floyd last night and it works rather well (even on 24/96 FLAC files (y) ). If you're feeling perverse you can set it to output this as a Dolby Prologic 2 signal instead (for an external decoder). You might want to lower the numbers by 10% or so (as shown) to avoid any clipping on the rear outputs though.

Guess there's no reason why you can't use this method to decode QS files as well, though I haven't got any samples to try and I believe Prologic 2 works well on QS files anyway?


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Ok, it turns out I was talking rubbish and hadn't appreciated that SQ works on 90 degree phase shifting not 180. If an admin comes across this thread please feel free to remove it. :mad:@:
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