Wait for the renderer even on WASAPI.

After weeks of investigation, Henrik has been unable find a WASAPI
buffer size that works for all users.  Many users are still reporting
glitches.  Thus its time to put the WaitTillDataReady() back. :(

BUG=171651
TEST=none

Review URL: https://codereview.chromium.org/12380074

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@185650 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 15 insertions, 6 deletions

diff --git a/media/audio/audio_output_controller.cc b/media/audio/audio_output_controller.cc
index 9990389..9120706 100644
--- a/media/audio/audio_output_controller.cc
+++ b/media/audio/audio_output_controller.cc
@@ -273,6 +273,16 @@ int AudioOutputController::OnMoreIOData(AudioBus* source,
   DisallowEntryToOnMoreIOData();
   TRACE_EVENT0("audio", "AudioOutputController::OnMoreIOData");
 
+  // The OS level audio APIs on Linux and Windows all have problems requesting
+  // data on a fixed interval.  Sometimes they will issue calls back to back
+  // which can cause glitching, so wait until the renderer is ready for Read().
+  //
+  // See many bugs for context behind this decision: http://crbug.com/170498,
+  // http://crbug.com/171651, http://crbug.com/174985, and more.
+#if defined(OS_WIN) || defined(OS_LINUX)
+  WaitTillDataReady();
+#endif
+
   const int frames = sync_reader_->Read(source, dest);
   DCHECK_LE(0, frames);
   sync_reader_->UpdatePendingBytes(
@@ -284,13 +294,12 @@ int AudioOutputController::OnMoreIOData(AudioBus* source,
 
 void AudioOutputController::WaitTillDataReady() {
   base::Time start = base::Time::Now();
-  // Wait for up to 1.5 seconds for DataReady().  1.5 seconds was chosen because
-  // it's larger than the playback time of the WaveOut buffer size using the
-  // minimum supported sample rate: 4096 / 3000 = ~1.4 seconds.  Even a client
-  // expecting real time playout should be able to fill in this time.
-  const base::TimeDelta max_wait = base::TimeDelta::FromMilliseconds(1500);
+  // Wait for up to 683ms for DataReady().  683ms was chosen because it's larger
+  // than the playback time of the WaveOut buffer size using the minimum
+  // supported sample rate: 2048 / 3000 = ~683ms.
+  const base::TimeDelta kMaxWait = base::TimeDelta::FromMilliseconds(683);
   while (!sync_reader_->DataReady() &&
-         ((base::Time::Now() - start) < max_wait)) {
+         ((base::Time::Now() - start) < kMaxWait)) {
     base::PlatformThread::YieldCurrentThread();
   }
 }