Avoids irregular OnMoreData callbacks on Windows using Core Audio

media/audio/win/audio_unified_win.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.
 
 #include "media/audio/win/audio_unified_win.h"
 
 #include <Functiondiscoverykeys_devpkey.h>
 
 #include "base/debug/trace_event.h"
 #include "base/time.h"
@@ skipping 228 matching lines @@
   }
 
   // Start input streaming data between the endpoint buffer and the audio
   // engine.
   HRESULT hr = audio_input_client_->Start();
   if (FAILED(hr)) {
     StopAndJoinThread(hr);
     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.
   hr = audio_output_client_->Start();
   if (FAILED(hr)) {
     StopAndJoinThread(hr);
     return;
   }
 }
 
@@ skipping 295 matching lines @@
 void WASAPIUnifiedStream::StopAndJoinThread(HRESULT err) {
   CHECK(GetCurrentThreadId() == creating_thread_id_);
   DCHECK(audio_io_thread_.get());
   SetEvent(stop_streaming_event_.Get());
   audio_io_thread_->Join();
   audio_io_thread_.reset();
   HandleError(err);
 }
 
 }  // namespace media