Merge 149119 to 1180 (M21) - Change NumberOfWaveOutBuffers() to return 3 for Windows >= Vista (inst…

media/audio/audio_util.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Software adjust volume of samples, allows each audio stream its own
 // volume without impacting master volume for chrome and other applications.
 
 // Implemented as templates to allow 8, 16 and 32 bit implementations.
 // 8 bit is unsigned and biased by 128.
 
@@ skipping 507 matching lines @@
   // Note: that function correctly returns that Windows Server 2003 does not
   // support WASAPI.
   return base::win::GetVersion() >= base::win::VERSION_VISTA;
 }
 
 int NumberOfWaveOutBuffers() {
   // Simple heuristic: use 3 buffers on single-core system or on Vista,
   // 2 otherwise.
   // Entire Windows audio stack was rewritten for Windows Vista, and wave out
   // API is simulated on top of new API, so there is noticeable performance
-  // degradation compared to Windows XP. Part of regression was fixed in
-  // Windows 7. Maybe it is fixed in Vista Serice Pack, but let's be cautious.
+  // degradation compared to Windows XP. Part of regression was apparently fixed
+  // in Windows 7, but problems remain at least with some configurations.
   if ((base::SysInfo::NumberOfProcessors() < 2) ||
-      (base::win::GetVersion() == base::win::VERSION_VISTA)) {
+      (base::win::GetVersion() >= base::win::VERSION_VISTA)) {
     return 3;
   }
   return 2;
 }
 
 #endif
 
 }  // namespace media