Exposes a shlib interface for media/audio path.

chromecast/media/audio/cast_audio_manager.cc

+// Copyright 2015 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 "chromecast/media/audio/cast_audio_manager.h"
+
+#include "base/logging.h"
+#include "chromecast/media/audio/chromecast_device_audio_output_stream.h"
+#include "chromecast/public/cast_audio_output_device.h"
+#include "chromecast/public/cast_audio_stream.h"
+
+namespace chromecast {
+
+namespace {
+
+// Default parameters to provide for input stream.
+const int kDefaultBitsPerSample = 16;
+const int kDefaultInputBufferSize = 1024;
+const int kDefaultSampleRate = 32000;
+
+// Utility to convert media::AudioParameters to chromecast::AudioParameters.
+// TODO(slan): Move these utilties to a central location.
+chromecast::AudioParameters FromChromiumParams(
+    const media::AudioParameters& in_params) {
+  chromecast::AudioParameters out_params;
+  out_params.sample_rate = in_params.sample_rate();
+  out_params.bits_per_sample = in_params.bits_per_sample();
+  out_params.frames_per_buffer = in_params.frames_per_buffer();
+  out_params.channels = in_params.channels();
+  return out_params;
+}
+
+// Utility to convert chromecast::AudioParameters to media::AudioParameters.
+// TODO(slan): Move these utilties to a central location.
+media::AudioParameters FromChromecastParams(
+    const chromecast::AudioParameters& in_params) {
+  return media::AudioParameters(
+      media::AudioParameters::AUDIO_PCM_LINEAR,
+      media::GuessChannelLayout(in_params.channels), in_params.sample_rate,
+      in_params.bits_per_sample, in_params.frames_per_buffer);
+}

[byungchul, 2015/04/27 17:38:05]

a blank line below here please.

[slan, 2015/04/28 00:11:38]

Done.

+}  // namespace
+
+CastAudioManager::CastAudioManager(media::AudioLogFactory* audio_log_factory,
+                                   CastAudioOutputDevice* output_device)
+    : media::AudioManagerBase(audio_log_factory),
+      audio_output_device_(output_device) {
+  CHECK(audio_output_device_);
+  SetMaxOutputStreamsAllowed(
+      audio_output_device_->GetMaximumOutputStreamsAllowed());
+}
+
+CastAudioManager::~CastAudioManager() {
+  Shutdown();
+}
+
+bool CastAudioManager::HasAudioOutputDevices() {
+  return true;
+}
+
+bool CastAudioManager::HasAudioInputDevices() {
+  return false;
+}
+
+void CastAudioManager::ShowAudioInputSettings() {
+  LOG(WARNING) << "No support for input audio devices.";
+}
+
+void CastAudioManager::GetAudioInputDeviceNames(
+    media::AudioDeviceNames* device_names) {
+  DCHECK(device_names->empty());

[byungchul, 2015/04/27 17:38:05]

Is this necessary?

[slan, 2015/04/28 00:11:38]

No. Removed.

+  LOG(WARNING) << "No support for input audio devices.";
+}
+
+media::AudioParameters CastAudioManager::GetInputStreamParameters(
+    const std::string& device_id) {
+  // TODO(damienv): Providing the default AudioParameters

[erickung1, 2015/04/25 08:38:31]

This can be someone else name who will make the change. :)

[slan, 2015/04/28 00:11:38]

Done. + bug assigned b/20630187

+  // (i.e. invalid parameters) impacts also the output parameter selection
+  // during WebAudio playback (and it fails).
+  // Figure out why.
+  LOG(WARNING) << "No support for input audio devices.";
+  return media::AudioParameters(media::AudioParameters::AUDIO_PCM_LOW_LATENCY,
+                                media::CHANNEL_LAYOUT_STEREO,
+                                kDefaultSampleRate, kDefaultBitsPerSample,

[byungchul, 2015/04/27 17:38:05]

wrap line after , then one argument per line

[slan, 2015/04/28 00:11:38]

Done.

+                                kDefaultInputBufferSize);
+}
+
+media::AudioInputStream* CastAudioManager::MakeLinearInputStream(
+    const media::AudioParameters& params,
+    const std::string& device_id) {
+  LOG(WARNING) << "No support for input audio devices";
+  return nullptr;
+}
+
+media::AudioInputStream* CastAudioManager::MakeLowLatencyInputStream(
+    const media::AudioParameters& params,
+    const std::string& device_id) {
+  LOG(WARNING) << "No support for input audio devices";
+  return nullptr;
+}
+
+media::AudioOutputStream* CastAudioManager::MakeLinearOutputStream(
+    const media::AudioParameters& params) {
+  DCHECK_EQ(media::AudioParameters::AUDIO_PCM_LINEAR, params.format());
+  return MakeCastOutputStream(params);
+}
+
+media::AudioOutputStream* CastAudioManager::MakeLowLatencyOutputStream(
+    const media::AudioParameters& params,
+    const std::string& device_id) {
+  DCHECK_EQ(media::AudioParameters::AUDIO_PCM_LOW_LATENCY, params.format());
+  return MakeCastOutputStream(params);
+}
+
+media::AudioParameters CastAudioManager::GetPreferredOutputStreamParameters(
+    const std::string& output_device_id,
+    const media::AudioParameters& suggested) {
+  // Convert the suggested params into the chromecast variety.
+  chromecast::AudioParameters params = FromChromiumParams(suggested);
+
+  // Get the preferences. Convert them back to Chromium params and return.
+  params = audio_output_device_->GetPreferredOutputStreamParameters(params);
+  return FromChromecastParams(params);
+}
+
+media::AudioOutputStream* CastAudioManager::MakeCastOutputStream(
+    const media::AudioParameters& params) {
+  // Get the Cast output stream.
+  chromecast::AudioParameters chromecast_params = FromChromiumParams(params);
+  chromecast::CastAudioOutputStream* stream =
+      audio_output_device_->MakeOutputStream(chromecast_params);
+  if (!stream)
+    return nullptr;
+
+  // Host a pass thru interface to translate calls between the stream and the
+  // consumer.
+  streams_.push_back(make_linked_ptr(
+      new ChromecastDeviceAudioOutputStream(stream, chromecast_params)));

[byungchul, 2015/04/27 17:38:05]

It is not correct since this function returns a raw pointer. You cannot prevent
the object being deleted. What is streams_ for? It is not used for now.

[slan, 2015/04/28 00:11:38]

We need to return a raw pointer to satisfy the ::media::AudioManager interface.
This does not transfer ownership of the returned pointer to the caller.
|streams_| is the container for the implementations of
::media::AudioOutputStream. These are owned by this class.

+  return streams_.back().get();
+}
+
+}  // namespace chromecast