Adds Analog Gain Control (AGC) to the WebRTC client.

media/audio/win/wavein_input_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/wavein_input_win.h"
 
-#include <windows.h>
-#include <mmsystem.h>
 #pragma comment(lib, "winmm.lib")
 
 #include "base/logging.h"
 #include "media/audio/audio_io.h"
 #include "media/audio/audio_util.h"
 #include "media/audio/win/audio_manager_win.h"
 #include "media/audio/win/device_enumeration_win.h"
 
 namespace {
-const int kStopInputStreamCallbackTimeout = 3000; // Three seconds.
+const int kStopInputStreamCallbackTimeout = 3000;  // Three seconds.
 }
 
 using media::AudioDeviceNames;
 
 // Our sound buffers are allocated once and kept in a linked list using the
 // the WAVEHDR::dwUser variable. The last buffer points to the first buffer.
 static WAVEHDR* GetNextBuffer(WAVEHDR* current) {
   return reinterpret_cast<WAVEHDR*>(current->dwUser);
 }
 
@@ skipping 165 matching lines @@
 
 void PCMWaveInAudioInputStream::SetVolume(double volume) {
   // TODO(henrika): Add volume support using the Audio Mixer API.
 }
 
 double PCMWaveInAudioInputStream::GetVolume() {
   // TODO(henrika): Add volume support using the Audio Mixer API.
   return 0.0;
 }
 
+void PCMWaveInAudioInputStream::SetAutomaticGainControl(bool enabled) {
+  // TODO(henrika): Add AGC support when volume control has been added.
+  NOTIMPLEMENTED();
+}
+
+bool PCMWaveInAudioInputStream::GetAutomaticGainControl() {
+  // TODO(henrika): Add AGC support when volume control has been added.
+  NOTIMPLEMENTED();
+  return false;
+}
+
 void PCMWaveInAudioInputStream::HandleError(MMRESULT error) {
   DLOG(WARNING) << "PCMWaveInAudio error " << error;
   callback_->OnError(this, error);
 }
 
 void PCMWaveInAudioInputStream::QueueNextPacket(WAVEHDR *buffer) {
   MMRESULT res = ::waveInAddBuffer(wavein_, buffer, sizeof(WAVEHDR));
   if (res != MMSYSERR_NOERROR)
     HandleError(res);
 }
@@ skipping 39 matching lines @@
                                              DWORD_PTR instance,
                                              DWORD_PTR param1, DWORD_PTR) {
   PCMWaveInAudioInputStream* obj =
       reinterpret_cast<PCMWaveInAudioInputStream*>(instance);
 
   if (msg == WIM_DATA) {
     // WIM_DONE indicates that the driver is done with our buffer. We pass it
     // to the callback and check if we need to stop playing.
     // It should be OK to assume the data in the buffer is what has been
     // recorded in the soundcard.
+    // TODO(henrika): the |volume| parameter is always set to zero since there
+    // is currently no support for controlling the microphone volume level.
     WAVEHDR* buffer = reinterpret_cast<WAVEHDR*>(param1);
     obj->callback_->OnData(obj, reinterpret_cast<const uint8*>(buffer->lpData),
                            buffer->dwBytesRecorded,
-                           buffer->dwBytesRecorded);
+                           buffer->dwBytesRecorded,
+                           0.0);
 
     if (obj->state_ == kStateStopping) {
       // The main thread has called Stop() and is waiting to issue waveOutReset
       // which will kill this thread. We should not enter AudioSourceCallback
       // code anymore.
       ::SetEvent(obj->stopped_event_);
     } else if (obj->state_ == kStateStopped) {
       // Not sure if ever hit this but just in case.
     } else {
       // Queue the finished buffer back with the audio driver. Since we are
       // reusing the same buffers we can get away without calling
       // waveInPrepareHeader.
       obj->QueueNextPacket(buffer);
     }
   } else if (msg == WIM_CLOSE) {
     // We can be closed before calling Start, so it is possible to have a
     // null callback at this point.
     if (obj->callback_)
       obj->callback_->OnClose(obj);
   }
 }