Adds support for 16kHz input sample rate and mono channel config. in WebRTC.

media/audio/win/audio_low_latency_input_win.cc

 // Copyright (c) 2011 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_low_latency_input_win.h"
 
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/utf_string_conversions.h"
 #include "media/audio/audio_util.h"
@@ skipping 166 matching lines @@
     sink_ = NULL;
   }
 
   // Inform the audio manager that we have been closed. This will cause our
   // destruction.
   manager_->ReleaseInputStream(this);
 }
 
 // static
 double WASAPIAudioInputStream::HardwareSampleRate(ERole device_role) {
+  base::win::ScopedCoMem<WAVEFORMATEX> audio_engine_mix_format;
+  HRESULT hr = GetMixFormat(device_role, &audio_engine_mix_format);
+  if (FAILED(hr)) {
+    NOTREACHED() << "error code: " << hr;
+    return 0.0;
+  }
+
+  return static_cast<double>(audio_engine_mix_format->nSamplesPerSec);
+}
+
+// static
+size_t WASAPIAudioInputStream::HardwareChannelCount(ERole device_role) {
+  base::win::ScopedCoMem<WAVEFORMATEX> audio_engine_mix_format;
+  HRESULT hr = GetMixFormat(device_role, &audio_engine_mix_format);
+  if (FAILED(hr)) {
+    NOTREACHED() << "error code: " << hr;
+    return CHANNEL_LAYOUT_NONE;
+  }
+
+  return audio_engine_mix_format->nChannels;
+}
+
+// static
+HRESULT WASAPIAudioInputStream::GetMixFormat(ERole device_role,
+                                             WAVEFORMATEX** device_format) {
   // It is assumed that this static method is called from a COM thread, i.e.,
   // CoInitializeEx() is not called here to avoid STA/MTA conflicts.
   ScopedComPtr<IMMDeviceEnumerator> enumerator;
   HRESULT hr =  CoCreateInstance(__uuidof(MMDeviceEnumerator),
                                  NULL,
                                  CLSCTX_INPROC_SERVER,
                                  __uuidof(IMMDeviceEnumerator),
                                  enumerator.ReceiveVoid());
-  if (FAILED(hr)) {
-    NOTREACHED() << "error code: " << hr;
-    return 0.0;
-  }
+  if (FAILED(hr))
+    return hr;
 
   ScopedComPtr<IMMDevice> endpoint_device;
   hr = enumerator->GetDefaultAudioEndpoint(eCapture,
                                            device_role,
                                            endpoint_device.Receive());
   if (FAILED(hr)) {
     // This will happen if there's no audio capture device found or available
     // (e.g. some audio cards that have inputs will still report them as
     // "not found" when no mic is plugged into the input jack).
     LOG(WARNING) << "No audio end point: " << std::hex << hr;
-    return 0.0;
+    return hr;
   }
 
   ScopedComPtr<IAudioClient> audio_client;
   hr = endpoint_device->Activate(__uuidof(IAudioClient),
                                  CLSCTX_INPROC_SERVER,
                                  NULL,
                                  audio_client.ReceiveVoid());
-  if (FAILED(hr)) {
-    NOTREACHED() << "error code: " << hr;
-    return 0.0;
-  }
+  if (SUCCEEDED(hr))
+    hr = audio_client->GetMixFormat(device_format);
 
-  base::win::ScopedCoMem<WAVEFORMATEX> audio_engine_mix_format;
-  hr = audio_client->GetMixFormat(&audio_engine_mix_format);
-  if (FAILED(hr)) {
-    NOTREACHED() << "error code: " << hr;
-    return 0.0;
-  }
-
-  return static_cast<double>(audio_engine_mix_format->nSamplesPerSec);
+  return hr;
 }
 
 void WASAPIAudioInputStream::Run() {
   ScopedCOMInitializer com_init(ScopedCOMInitializer::kMTA);
 
   // Increase the thread priority.
   capture_thread_->SetThreadPriority(base::kThreadPriority_RealtimeAudio);
 
   // Enable MMCSS to ensure that this thread receives prioritized access to
   // CPU resources.
@@ skipping 273 matching lines @@
   hr = audio_client_->SetEventHandle(audio_samples_ready_event_.Get());
   if (FAILED(hr))
     return hr;
 
   // Get access to the IAudioCaptureClient interface. This interface
   // enables us to read input data from the capture endpoint buffer.
   hr = audio_client_->GetService(__uuidof(IAudioCaptureClient),
                                  audio_capture_client_.ReceiveVoid());
   return hr;
 }