[openMSX-commits] SF.net SVN: openmsx:[12199] openmsx/trunk/src/sound/BlipBuffer.hh

[<m97...@us...>]

Revision: 12199
          http://openmsx.svn.sourceforge.net/openmsx/?rev=12199&view=rev
Author:   m9710797
Date:     2011-07-02 18:50:22 +0000 (Sat, 02 Jul 2011)

Log Message:
-----------
Increase the resolution of the pre-calculated impulse-response in BlipBuffer

In this BASIC test:
  SOUND 0,0
  SOUND 1,0
  SOUND 8,15
You could here same noise when using the blip-resampler (not with the hq
resampler). After this patch the noise with blip is a _lot_ less. (AFAIK it's
not possible to completely remove it with the current design of BlipBuffer).

The original value for BLIP_PHASE_BITS was 6, this patch changes it to 10. Our
tests showed that for values 9 and above the sound quality doesn't improve
anymore. But just to be on the save side we took one more (it might be the case
that for other tests there still is a minor difference between 9 and 10).

Modified Paths:
--------------
    openmsx/trunk/src/sound/BlipBuffer.hh

Modified: openmsx/trunk/src/sound/BlipBuffer.hh
===================================================================
--- openmsx/trunk/src/sound/BlipBuffer.hh	2011-07-01 16:24:36 UTC (rev 12198)
+++ openmsx/trunk/src/sound/BlipBuffer.hh	2011-07-02 18:50:22 UTC (rev 12199)
@@ -18,7 +18,7 @@
 public:
 	// Number bits in phase offset. Fewer than 6 bits (64 phase offsets) results in
 	// noticeable broadband noise when synthesizing high frequency square waves.
-	static const int BLIP_PHASE_BITS = 6;
+	static const int BLIP_PHASE_BITS = 10;
 	typedef FixedPoint<BLIP_PHASE_BITS> TimeIndex;
 
 	BlipBuffer();


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