Avoids irregular OnMoreData callbacks on Windows using Core Audio

media/audio/audio_util.cc

Index: media/audio/audio_util.cc
diff --git a/media/audio/audio_util.cc b/media/audio/audio_util.cc
index 4c446dd8012bb1e9cb1d45ac119aa0c3d1341f3e..94490576caa015b6ea11826a4a9148a6ca2d27ed 100644
--- a/media/audio/audio_util.cc
+++ b/media/audio/audio_util.cc
@@ -242,6 +242,8 @@ int GetAudioInputHardwareSampleRate(const std::string& device_id) {
 }
 
 size_t GetAudioHardwareBufferSize() {
+  // TODO(henrika): resolve conflict on Windows where we today only allow

[tommi (sloooow) - chröme, 2013/01/31 13:42:08]

Move this todo into the OS_WIN section?
Also, can you clarify what the conflict is?

[henrika (OOO until Aug 14), 2013/01/31 14:29:38]

Done.

+  // the native buffer size.
   int user_buffer_size = GetUserBufferSize();
   if (user_buffer_size)
     return user_buffer_size;
@@ -257,7 +259,7 @@ size_t GetAudioHardwareBufferSize() {
   return 128;
 #elif defined(OS_WIN)
   // Buffer size to use when a proper size can't be determined from the system.
-  static const int kFallbackBufferSize = 4096;
+  static const int kFallbackBufferSize = 1440;

[DaleCurtis, 2013/01/31 02:34:33]

Hmm, this is going to bust XP. If WaveOut isn't supported you ned to return
4096.

[henrika (OOO until Aug 14), 2013/01/31 14:29:38]

I hope you did not think I meant to do this change ;-)

It was a pure testing mistake. Will revert of course. Thanks!

 
   if (!CoreAudioUtil::IsSupported()) {
     // Fall back to Windows Wave implementation on Windows XP or lower
@@ -273,42 +275,10 @@ size_t GetAudioHardwareBufferSize() {
     return 256;
   }
 
-  // TODO(henrika): remove when the --enable-webaudio-input flag is no longer
-  // utilized.
-  if (cmd_line->HasSwitch(switches::kEnableWebAudioInput)) {
-    AudioParameters params;
-    HRESULT hr = CoreAudioUtil::GetPreferredAudioParameters(eRender, eConsole,
-                                                            &params);
-    return FAILED(hr) ? kFallbackBufferSize : params.frames_per_buffer();
-  }
-
-  // This call must be done on a COM thread configured as MTA.
-  // TODO(tommi): http://code.google.com/p/chromium/issues/detail?id=103835.
-  int mixing_sample_rate =
-      WASAPIAudioOutputStream::HardwareSampleRate(eConsole);
-
-  // Windows will return a sample rate of 0 when no audio output is available
-  // (i.e. via RemoteDesktop with remote audio disabled), but we should never
-  // return a buffer size of zero.
-  if (mixing_sample_rate == 0)
-    return kFallbackBufferSize;
-
-  // Use different buffer sizes depening on the sample rate . The existing
-  // WASAPI implementation is tuned to provide the most stable callback
-  // sequence using these combinations.
-  if (mixing_sample_rate % 11025 == 0)
-    // Use buffer size of ~10.15873 ms.
-    return (112 * (mixing_sample_rate / 11025));
-
-  if (mixing_sample_rate % 8000 == 0)
-    // Use buffer size of 10ms.
-    return (80 * (mixing_sample_rate / 8000));
-
-  // Ensure we always return a buffer size which is somewhat appropriate.
-  LOG(ERROR) << "Unknown sample rate " << mixing_sample_rate << " detected.";
-  if (mixing_sample_rate > limits::kMinSampleRate)
-    return (mixing_sample_rate / 100);
-  return kFallbackBufferSize;
+  AudioParameters params;
+  HRESULT hr = CoreAudioUtil::GetPreferredAudioParameters(eRender, eConsole,
+                                                          &params);
+  return FAILED(hr) ? kFallbackBufferSize : params.frames_per_buffer();
 #else
   return 2048;
 #endif