Avoids irregular OnMoreData callbacks on Windows using Core Audio

media/audio/win/audio_unified_win.cc

Index: media/audio/win/audio_unified_win.cc
diff --git a/media/audio/win/audio_unified_win.cc b/media/audio/win/audio_unified_win.cc
index 677f9e0260aea59c10879be3e4daef4e10a206e7..de84aaa6e5b6d6c57fe7aa8bb588ac09969a3f4b 100644
--- a/media/audio/win/audio_unified_win.cc
+++ b/media/audio/win/audio_unified_win.cc
@@ -246,12 +246,15 @@ void WASAPIUnifiedStream::Start(AudioSourceCallback* callback) {
     return;
   }
 
-  // Reset the counter for number of rendered frames taking into account the
-  // fact that we always initialize the render side with silence.
-  UINT32 num_queued_frames = 0;
-  audio_output_client_->GetCurrentPadding(&num_queued_frames);
-  DCHECK_EQ(num_queued_frames, endpoint_render_buffer_size_frames_);
-  num_written_frames_ = num_queued_frames;
+  // Ensure that the endpoint buffer is prepared with silence.
+  if (share_mode_ == AUDCLNT_SHAREMODE_SHARED) {
+    if (!CoreAudioUtil::FillRenderEndpointBufferWithSilence(
+        audio_output_client_, audio_render_client_)) {

[tommi (sloooow) - chröme, 2013/01/31 16:18:24]

same here

[henrika (OOO until Aug 14), 2013/02/01 10:55:56]

Done.

+      DLOG(WARNING) << "Failed to prepare endpoint buffers with silence.";
+      return;
+    }
+  }
+  num_written_frames_ = endpoint_render_buffer_size_frames_;
 
   // Start output streaming data between the endpoint buffer and the audio
   // engine.