Add recording capability to AudioManager, and implemented on windows using the WaveIn APIs.

media/audio/win/audio_manager_win.cc

-// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
+// Copyright (c) 2006-2010 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_io.h"
 
 #include <windows.h>
 #include <mmsystem.h>
 
 #include "base/at_exit.h"
 #include "base/basictypes.h"
 #include "media/audio/fake_audio_output_stream.h"
 #include "media/audio/win/audio_manager_win.h"
+#include "media/audio/win/wavein_input_win.h"
 #include "media/audio/win/waveout_output_win.h"
 
 namespace {
 
 // The next 3 constants are some sensible limits to prevent integer overflow
 // at this layer.
 // Up to 6 channels can be passed to the driver.
 // This should work, given the right drivers, but graceful error handling is
 // needed.
 // In theory 7.1 could also be supported, but it has not been tested.
 // The 192 Khz constant is the frequency of quicktime lossless audio codec.
 // MP4 is limited to 96 Khz, and mp3 is limited to 48 Khz.
 // OGG vorbis was initially limited to 96 Khz, but recent tools are unlimited.
 // 192 Khz is also the limit on most PC audio hardware.  The minimum is 100 Hz.
 // Humans range is 20 to 20000 Hz.  Below 20 can be felt (woofer).
 
 const int kMaxChannels = 6;
 const int kMaxSampleRate = 192000;
 const int kMaxBitsPerSample = 64;
 
+const int kMaxInputChannels = 2;
+const int kMaxSamplesPerPacket = kMaxSampleRate;
+// We use 3 buffers for recording audio so that if a recording callback takes
+// some time to return we won't lose audio. More buffers while recording are
+// ok because they don't introduce any delay in recording, unlike in playback
+// where you first need to fill in that number of buffers before starting to
+// play.
+const int kNumInputBuffers = 3;
+
 AudioManagerWin* g_audio_manager = NULL;
 
 }  // namespace.
 
 bool AudioManagerWin::HasAudioOutputDevices() {
   return (::waveOutGetNumDevs() != 0);
 }
 
+bool AudioManagerWin::HasAudioInputDevices() {
+  return (::waveInGetNumDevs() != 0);
+}
+
 // Factory for the implementations of AudioOutputStream. Two implementations
 // should suffice most windows user's needs.
 // - PCMWaveOutAudioOutputStream: Based on the waveOutWrite API (in progress)
 // - PCMDXSoundAudioOutputStream: Based on DirectSound or XAudio (future work).
 AudioOutputStream* AudioManagerWin::MakeAudioOutputStream(
     Format format,
     int channels,
     int sample_rate,
     char bits_per_sample) {
   if ((channels > kMaxChannels) || (channels <= 0) ||
       (sample_rate > kMaxSampleRate) || (sample_rate <= 0) ||
       (bits_per_sample > kMaxBitsPerSample) || (bits_per_sample <= 0))
     return NULL;
 
   if (format == AUDIO_MOCK) {
     return FakeAudioOutputStream::MakeFakeStream();
   } else if (format == AUDIO_PCM_LINEAR) {
     return new PCMWaveOutAudioOutputStream(this, channels, sample_rate, 3,
                                            bits_per_sample, WAVE_MAPPER);
   } else if (format == AUDIO_PCM_LOW_LATENCY) {
     // TODO(cpu): waveout cannot hit 20ms latency. Use other method.
     return new PCMWaveOutAudioOutputStream(this, channels, sample_rate, 2,
                                            bits_per_sample, WAVE_MAPPER);
   }
   return NULL;
 }
 
+// Factory for the implementations of AudioInputStream.
+AudioInputStream* AudioManagerWin::MakeAudioInputStream(
+    Format format,
+    int channels,
+    int sample_rate,
+    char bits_per_sample,
+    uint32 samples_per_packet) {
+  if ((channels > kMaxInputChannels) || (channels <= 0) ||
+      (sample_rate > kMaxSampleRate) || (sample_rate <= 0) ||
+      (bits_per_sample > kMaxBitsPerSample) || (bits_per_sample <= 0) ||
+      (samples_per_packet > kMaxSamplesPerPacket) || (samples_per_packet < 0))
+    return NULL;
+
+  if (format == AUDIO_MOCK) {
+    // TODO(satish): Add mock audio input stream.
+  } else if (format == AUDIO_PCM_LINEAR) {
+    return new PCMWaveInAudioInputStream(this, channels, sample_rate,
+                                         kNumInputBuffers, bits_per_sample,
+                                         samples_per_packet, WAVE_MAPPER);
+  }
+  return NULL;
+}
+
 void AudioManagerWin::ReleaseOutputStream(PCMWaveOutAudioOutputStream* stream) {
   if (stream)
     delete stream;
 }
 
+void AudioManagerWin::ReleaseInputStream(PCMWaveInAudioInputStream* stream) {
+  if (stream)
+    delete stream;
+}
+
 void AudioManagerWin::MuteAll() {
 }
 
 void AudioManagerWin::UnMuteAll() {
 }
 
 AudioManagerWin::~AudioManagerWin() {
 }
 
 void DestroyAudioManagerWin(void* param) {
   delete g_audio_manager;
   g_audio_manager = NULL;
 }
 
 AudioManager* AudioManager::GetAudioManager() {
   if (!g_audio_manager) {
     g_audio_manager = new AudioManagerWin();
     base::AtExitManager::RegisterCallback(&DestroyAudioManagerWin, NULL);
   }
   return g_audio_manager;
 }