Bypass audio resampler on XP / non-WASAPI wave out path.

media/audio/audio_output_resampler.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/audio_output_resampler.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/command_line.h"
 #include "base/compiler_specific.h"
@@ skipping 62 matching lines @@
 AudioOutputResampler::AudioOutputResampler(AudioManager* audio_manager,
                                            const AudioParameters& input_params,
                                            const AudioParameters& output_params,
                                            const base::TimeDelta& close_delay)
     : AudioOutputDispatcher(audio_manager, input_params),
       source_callback_(NULL),
       io_ratio_(1),
       close_delay_(close_delay),
       outstanding_audio_bytes_(0),
       output_params_(output_params) {
+  DCHECK_EQ(output_params_.format(), AudioParameters::AUDIO_PCM_LOW_LATENCY);
   Initialize();
   // Record UMA statistics for the hardware configuration.
   RecordStats(output_params_);
 }
 
 AudioOutputResampler::~AudioOutputResampler() {}
 
 void AudioOutputResampler::Initialize() {
   io_ratio_ = 1;
 
@@ skipping 33 matching lines @@
         params_.frames_per_buffer() != output_params_.frames_per_buffer()) {
       DVLOG(1) << "Rebuffering from " << params_.frames_per_buffer()
                << " to " << output_params_.frames_per_buffer();
       audio_fifo_.reset(new AudioPullFifo(
           params_.channels(), params_.frames_per_buffer(), base::Bind(
               &AudioOutputResampler::SourceCallback_Locked,
               base::Unretained(this))));
     }
 
     DVLOG(1) << "I/O ratio is " << io_ratio_;
+  } else {
+    DVLOG(1) << "Input and output params are the same; in pass-through mode.";
   }
 
   // TODO(dalecurtis): All this code should be merged into AudioOutputMixer once
   // we've stabilized the issues there.
   dispatcher_ = new AudioOutputDispatcherImpl(
       audio_manager_, output_params_, close_delay_);
 }
 
 bool AudioOutputResampler::OpenStream() {
   if (dispatcher_->OpenStream()) {
@@ skipping 18 matching lines @@
 
   // Record UMA statistics about the hardware which triggered the failure so we
   // can debug and triage later.
   UMA_HISTOGRAM_BOOLEAN("Media.FallbackToHighLatencyAudioPath", true);
   RecordFallbackStats(output_params_);
 
   // Open failed!  Attempt to open the output device in high latency mode using
   // a new high latency appropriate buffer size.  |kMinLowLatencyFrameSize| is
   // arbitrarily based on Pepper Flash's MAXIMUM frame size for low latency.
   static const int kMinLowLatencyFrameSize = 2048;
-  int frames_per_buffer = std::max(
-      std::min(params_.frames_per_buffer(), kMinLowLatencyFrameSize),
+  int frames_per_buffer = std::min(
+      std::max(params_.frames_per_buffer(), kMinLowLatencyFrameSize),
       static_cast<int>(GetHighLatencyOutputBufferSize(params_.sample_rate())));
 
   output_params_ = AudioParameters(
       AudioParameters::AUDIO_PCM_LINEAR, params_.channel_layout(),
       params_.sample_rate(), params_.bits_per_sample(), frames_per_buffer);
   Initialize();
 
   // Retry, if this fails, there's nothing left to do but report the error back.
   return dispatcher_->OpenStream();
 }
@@ skipping 115 matching lines @@
     source_callback_->OnError(stream, code);
 }
 
 void AudioOutputResampler::WaitTillDataReady() {
   base::AutoLock auto_lock(source_lock_);
   if (source_callback_ && !outstanding_audio_bytes_)
     source_callback_->WaitTillDataReady();
 }
 
 }  // namespace media