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/cast_audio_output_stream.h"
+#include "chromecast/public/cast_audio_stream.h"
+#include "chromecast/public/cast_audio_stream_provider.h"
+
+namespace media {
+
+namespace {
+
+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 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.
+AudioParameters FromChromecastParams(
+    const chromecast::AudioParameters& in_params) {
+  return AudioParameters(media::AudioParameters::AUDIO_PCM_LINEAR,
+                         GuessChannelLayout(in_params.channels),
+                         in_params.sample_rate, in_params.bits_per_sample,
+                         in_params.frames_per_buffer);
+}
+
+}  // namespace
+CastAudioManager::CastAudioManager(

[lcwu1, 2015/04/24 02:18:24]

Leave a vertical space above this line.

[slan, 2015/04/24 05:34:26]

Done.

+    AudioLogFactory* audio_log_factory,
+    chromecast::CastAudioStreamProvider* stream_provider)
+    : AudioManagerBase(audio_log_factory),
+      audio_stream_provider_(stream_provider) {
+  CHECK(audio_stream_provider_);
+  SetMaxOutputStreamsAllowed(
+      audio_stream_provider_->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(
+    AudioDeviceNames* device_names) {
+  DCHECK(device_names->empty());
+  LOG(WARNING) << "No support for input audio devices.";
+}
+
+AudioParameters CastAudioManager::GetInputStreamParameters(
+    const std::string& device_id) {
+  // TODO(damienv): Providing the default AudioParameters
+  // (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 AudioParameters(AudioParameters::AUDIO_PCM_LOW_LATENCY,
+                         CHANNEL_LAYOUT_STEREO, kDefaultSampleRate,
+                         kDefaultBitsPerSample, kDefaultInputBufferSize);
+}
+
+AudioInputStream* CastAudioManager::MakeLinearInputStream(
+    const AudioParameters& params,
+    const std::string& device_id) {
+  LOG(WARNING) << "No support for input audio devices";
+  return nullptr;
+}
+
+AudioInputStream* CastAudioManager::MakeLowLatencyInputStream(
+    const AudioParameters& params,
+    const std::string& device_id) {
+  LOG(WARNING) << "No support for input audio devices";
+  return nullptr;
+}
+
+AudioOutputStream* CastAudioManager::MakeLinearOutputStream(
+    const AudioParameters& params) {
+  DCHECK_EQ(AudioParameters::AUDIO_PCM_LINEAR, params.format());
+  return MakeCastOutputStream(params);
+}
+
+AudioOutputStream* CastAudioManager::MakeLowLatencyOutputStream(
+    const AudioParameters& params,
+    const std::string& device_id) {
+  DCHECK_EQ(AudioParameters::AUDIO_PCM_LOW_LATENCY, params.format());
+  return MakeCastOutputStream(params);
+}
+
+AudioParameters CastAudioManager::GetPreferredOutputStreamParameters(
+    const std::string& output_device_id,
+    const 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_stream_provider_->GetPreferredOutputStreamParameters(params);
+  return FromChromecastParams(params);
+}
+
+AudioOutputStream* CastAudioManager::MakeCastOutputStream(
+    const AudioParameters& params) {
+  // Get the Cast output stream.
+  chromecast::AudioParameters chromecast_params = FromChromiumParams(params);
+  chromecast::AudioOutputStream* stream =
+      audio_stream_provider_->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 CastAudioOutputStream(stream, chromecast_params)));
+  return streams_.back().get();
+}
+
+}  // namespace media