Rename a header and some methods to make way for subsequent audio recording additions.

Renaming audio_output.h to audio_io.h as future patches will add audio recording code to this file.
Also renamed a couple of methods to make it clear that these are for audio playback/output and similar methods will be added for audio capture/recording soon.
BUG=none
TEST=no change in functionality.

Review URL: http://codereview.chromium.org/2962006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@52125 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 94 insertions, 0 deletions

diff --git a/media/audio/win/audio_manager_win.cc b/media/audio/win/audio_manager_win.cc
new file mode 100644
index 0000000..81a59f5
--- /dev/null
+++ b/media/audio/win/audio_manager_win.cc
@@ -0,0 +1,94 @@
+// Copyright (c) 2006-2008 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/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;
+
+AudioManagerWin* g_audio_manager = NULL;
+
+}  // namespace.
+
+bool AudioManagerWin::HasAudioOutputDevices() {
+  return (::waveOutGetNumDevs() != 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;
+}
+
+void AudioManagerWin::ReleaseOutputStream(PCMWaveOutAudioOutputStream* 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;
+}