Use the correct number of WaveOut buffers on XP...

Reverts a buffer size increase added in http://crrev.com/168111
and hacks added in http://crrev.com/169553

BUG=161307
TEST=Flash, HTML5 playback smoothly -- even in the background.

Review URL: https://chromiumcodereview.appspot.com/12155003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@180102 0039d316-1c4b-4281-b951-d872f2087c98

media/audio/audio_output_resampler.cc

@@ -21,10 +21,6 @@
 #include "media/base/limits.h"
 #include "media/base/media_switches.h"
 
-#if defined(OS_WIN)
-#include "media/audio/win/core_audio_util_win.h"
-#endif
-
 namespace media {
 
 class OnMoreDataConverter
@@ -77,10 +73,6 @@ class OnMoreDataConverter
   // parameters.
   AudioConverter audio_converter_;
 
-  // If we're using WaveOut on Windows' we always have to wait for DataReady()
-  // before calling |source_callback_|.
-  bool waveout_wait_hack_;
-
   DISALLOW_COPY_AND_ASSIGN(OnMoreDataConverter);
 };
 
@@ -287,22 +279,10 @@ OnMoreDataConverter::OnMoreDataConverter(const AudioParameters& input_params,
     : source_callback_(NULL),
       source_bus_(NULL),
       input_bytes_per_second_(input_params.GetBytesPerSecond()),
-      audio_converter_(input_params, output_params, false),
-      waveout_wait_hack_(false) {
+      audio_converter_(input_params, output_params, false) {
   io_ratio_ =
       static_cast<double>(input_params.GetBytesPerSecond()) /
       output_params.GetBytesPerSecond();
-
-  // TODO(dalecurtis): We should require all render side clients to use a
-  // buffer size that's a multiple of the hardware buffer size scaled by the
-  // request_sample_rate / hw_sample_rate.  Doing so ensures each hardware
-  // request for audio data results in only a single render side callback and
-  // would allow us to remove this hack.  See http://crbug.com/162207.
-#if defined(OS_WIN)
-  waveout_wait_hack_ =
-      output_params.format() == AudioParameters::AUDIO_PCM_LINEAR ||
-      !CoreAudioUtil::IsSupported();
-#endif
 }
 
 OnMoreDataConverter::~OnMoreDataConverter() {}
@@ -361,9 +341,6 @@ double OnMoreDataConverter::ProvideInput(AudioBus* dest,
       io_ratio_ * (current_buffers_state_.total_bytes() +
                    buffer_delay.InSecondsF() * input_bytes_per_second_);
 
-  if (waveout_wait_hack_)
-    source_callback_->WaitTillDataReady();
-
   // Retrieve data from the original callback.
   int frames = source_callback_->OnMoreIOData(
       source_bus_, dest, new_buffers_state);

media/audio/audio_util.cc

@@ -177,7 +177,7 @@ 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 = 2048;
 
   if (!CoreAudioUtil::IsSupported()) {
     // Fall back to Windows Wave implementation on Windows XP or lower

media/audio/win/audio_manager_win.cc

@@ -288,7 +288,8 @@ AudioOutputStream* AudioManagerWin::MakeLowLatencyOutputStream(
   if (!CoreAudioUtil::IsSupported()) {
     // Fall back to Windows Wave implementation on Windows XP or lower.
     DVLOG(1) << "Using WaveOut since WASAPI requires at least Vista.";
-    return new PCMWaveOutAudioOutputStream(this, params, 2, WAVE_MAPPER);
+    return new PCMWaveOutAudioOutputStream(
+        this, params, media::NumberOfWaveOutBuffers(), WAVE_MAPPER);
   }
 
   // TODO(henrika): remove once we properly handle input device selection.