[Chromecast] Plumbs raw audio through CMA backend.

chromecast/media/audio/cast_audio_output_stream.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_output_stream.h"
+
+#include "base/bind.h"
+#include "base/thread_task_runner_handle.h"
+#include "chromecast/media/audio/cast_audio_manager.h"
+#include "chromecast/media/cma/base/cast_decoder_buffer_impl.h"
+#include "chromecast/media/cma/base/decoder_buffer_adapter.h"
+#include "chromecast/media/cma/pipeline/frame_status_cb_impl.h"
+#include "chromecast/public/media/audio_pipeline_device.h"
+#include "chromecast/public/media/decoder_config.h"
+#include "chromecast/public/media/decrypt_context.h"
+#include "chromecast/public/media/media_clock_device.h"
+#include "chromecast/public/media/media_pipeline_backend.h"
+#include "media/audio/fake_audio_worker.h"
+#include "media/base/decoder_buffer.h"
+
+namespace chromecast {
+namespace media {
+
+namespace {
+bool InitClockDevice(MediaClockDevice* clock_device) {
+  DCHECK(clock_device);
+  DCHECK_EQ(clock_device->GetState(), MediaClockDevice::kStateUninitialized);
+
+  if (!clock_device->SetState(media::MediaClockDevice::kStateIdle))
+    return false;
+
+  if (!clock_device->ResetTimeline(0))
+    return false;
+
+  if (!clock_device->SetRate(1.0))
+    return false;
+
+  return true;
+}
+
+bool InitAudioDevice(const ::media::AudioParameters& audio_params,
+                     AudioPipelineDevice* audio_device) {
+  DCHECK(audio_device);
+  DCHECK_EQ(audio_device->GetState(), AudioPipelineDevice::kStateUninitialized);
+
+  AudioConfig audio_config;
+  audio_config.codec = kCodecPCM;
+  audio_config.sample_format = kSampleFormatS16;
+  audio_config.bytes_per_channel = audio_params.bits_per_sample() / 8;
+  audio_config.channel_number = audio_params.channels();
+  audio_config.samples_per_second = audio_params.sample_rate();
+  audio_config.extra_data = nullptr;
+  audio_config.extra_data_size = 0;
+  audio_config.is_encrypted = false;
+  if (!audio_device->SetConfig(audio_config))
+    return false;
+
+  if (!audio_device->SetState(AudioPipelineDevice::kStateIdle))
+    return false;
+
+  return true;
+}
+}  // namespace
+
+CastAudioOutputStream::CastAudioOutputStream(
+    const ::media::AudioParameters& audio_params,
+    CastAudioManager* audio_manager)
+    : audio_params_(audio_params),
+      audio_manager_(audio_manager),
+      volume_(1.0),
+      audio_device_busy_(false),
+      weak_factory_(this) {
+  VLOG(1) << "CastAudioOutputStream " << this << " created with "
+          << audio_params_.AsHumanReadableString();
+}
+
+CastAudioOutputStream::~CastAudioOutputStream() {}
+
+bool CastAudioOutputStream::Open() {
+  ::media::AudioParameters::Format format = audio_params_.format();
+  DCHECK((format == ::media::AudioParameters::AUDIO_PCM_LINEAR) ||
+         (format == ::media::AudioParameters::AUDIO_PCM_LOW_LATENCY));
+
+  ::media::ChannelLayout channel_layout = audio_params_.channel_layout();
+  if ((channel_layout != ::media::CHANNEL_LAYOUT_MONO) &&
+      (channel_layout != ::media::CHANNEL_LAYOUT_STEREO)) {
+    LOG(WARNING) << "Unsupported channel layout: " << channel_layout;
+    return false;
+  }
+  DCHECK_GE(audio_params_.channels(), 1);
+  DCHECK_LE(audio_params_.channels(), 2);
+
+  media_pipeline_backend_ = audio_manager_->CreateMediaPipelineBackend();
+  if (!media_pipeline_backend_) {
+    LOG(WARNING) << "Failed to create media pipeline backend.";
+    return false;
+  }
+
+  if (!InitClockDevice(media_pipeline_backend_->GetClock())) {
+    LOG(WARNING) << "Failed to initialize clock device.";
+    return false;
+  }
+
+  if (!InitAudioDevice(audio_params_, media_pipeline_backend_->GetAudio())) {
+    LOG(WARNING) << "Failed to initialize audio device.";
+    return false;
+  }
+
+  audio_bus_ = ::media::AudioBus::Create(audio_params_);
+  audio_worker_.reset(new ::media::FakeAudioWorker(
+      base::ThreadTaskRunnerHandle::Get(), audio_params_));
+
+  VLOG(1) << __FUNCTION__ << " : " << this;
+  return true;
+}
+
+void CastAudioOutputStream::Close() {
+  VLOG(1) << __FUNCTION__ << " : " << this;
+
+  if (media_pipeline_backend_) {
+    media_pipeline_backend_->GetClock()->SetState(MediaClockDevice::kStateIdle);
+    media_pipeline_backend_->GetAudio()->SetState(
+        AudioPipelineDevice::kStateIdle);
+  }
+
+  audio_worker_.reset();
+  audio_bus_.reset();
+  media_pipeline_backend_.reset();
+
+  // Signal to the manager that we're closed and can be removed.
+  // This should be the last call in the function as it deletes "this".
+  audio_manager_->ReleaseOutputStream(this);
+}
+
+void CastAudioOutputStream::Start(AudioSourceCallback* source_callback) {
+  MediaClockDevice* clock_device = media_pipeline_backend_->GetClock();
+  DCHECK(clock_device);
+  if (!clock_device->SetState(MediaClockDevice::kStateRunning)) {
+    LOG(WARNING) << "Failed to run clock device.";
+    return;
+  }
+  clock_device->SetRate(1.0f);
+
+  AudioPipelineDevice* audio_device = media_pipeline_backend_->GetAudio();
+  DCHECK(audio_device);
+  if (!audio_device->SetState(AudioPipelineDevice::kStateRunning)) {
+    LOG(WARNING) << "Failed to run audio device.";
+    return;
+  }
+
+  VLOG(1) << __FUNCTION__ << " : " << this;
+  audio_worker_->Start(base::Bind(&CastAudioOutputStream::PushFrame,
+                                  weak_factory_.GetWeakPtr(), source_callback));
+}
+
+void CastAudioOutputStream::Stop() {
+  VLOG(1) << __FUNCTION__ << " : " << this;
+
+  MediaClockDevice* clock_device = media_pipeline_backend_->GetClock();
+  DCHECK(clock_device);
+  clock_device->SetState(MediaClockDevice::kStateIdle);
+  clock_device->SetRate(0.0f);
+
+  AudioPipelineDevice* audio_device = media_pipeline_backend_->GetAudio();
+  DCHECK(audio_device);
+  audio_device->SetState(AudioPipelineDevice::kStatePaused);
+  audio_worker_->Stop();
+  audio_device_busy_ = false;
+}
+
+void CastAudioOutputStream::SetVolume(double volume) {
+  AudioPipelineDevice* audio_device = media_pipeline_backend_->GetAudio();
+  DCHECK(audio_device);
+  audio_device->SetStreamVolumeMultiplier(volume);
+  volume_ = volume;
+}
+
+void CastAudioOutputStream::GetVolume(double* volume) {
+  *volume = volume_;
+}
+
+void CastAudioOutputStream::PushFrame(AudioSourceCallback* source_callback) {
+  DCHECK(source_callback);
+  if (audio_device_busy_) {
+    // Skip pulling data if audio device is still busy.
+    LOG(WARNING) << __FUNCTION__ << " : " << this
+                 << " skipped because audio device is busy.";
+    return;
+  }
+
+  int frame_count = source_callback->OnMoreData(audio_bus_.get(), 0);
+  DCHECK_EQ(frame_count, audio_bus_->frames());
+  int buffer_size = frame_count * audio_params_.GetBytesPerFrame();
+  scoped_refptr<::media::DecoderBuffer> decoder_buffer(
+      new ::media::DecoderBuffer(buffer_size));
+  audio_bus_->ToInterleaved(frame_count, audio_params_.bits_per_sample() / 8,
+                            decoder_buffer->writable_data());
+
+  AudioPipelineDevice* audio_device = media_pipeline_backend_->GetAudio();
+  DCHECK(audio_device);
+  MediaComponentDevice::FrameStatus status = audio_device->PushFrame(
+      nullptr,  // decrypt_context
+      new CastDecoderBufferImpl(new DecoderBufferAdapter(decoder_buffer)),
+      new media::FrameStatusCBImpl(
+          base::Bind(&CastAudioOutputStream::OnPushFrameStatus,
+                     weak_factory_.GetWeakPtr(), source_callback)));
+
+  if (status == MediaComponentDevice::kFrameFailed) {
+    // Note: We cannot call OnPushFrameError directly because it will lead to
+    // a recursive lock, which is not supported by base::Lock.
+    // This callback is called with a lock held inside FakeAudioWorker.
+    // Calling FakeAudioWorker::Stop will try to acquire the lock again.
+    base::ThreadTaskRunnerHandle::Get()->PostTask(
+        FROM_HERE, base::Bind(&CastAudioOutputStream::OnPushFrameError,
+                              weak_factory_.GetWeakPtr(), source_callback));
+  } else if (status == MediaComponentDevice::kFramePending) {
+    audio_device_busy_ = true;
+  }
+}
+
+void CastAudioOutputStream::OnPushFrameStatus(
+    AudioSourceCallback* source_callback,
+    MediaComponentDevice::FrameStatus status) {
+  DCHECK(audio_device_busy_);
+  audio_device_busy_ = false;
+
+  DCHECK_NE(status, MediaComponentDevice::kFramePending);
+  if (status == MediaComponentDevice::kFrameFailed)
+    OnPushFrameError(source_callback);
+}
+
+void CastAudioOutputStream::OnPushFrameError(
+    AudioSourceCallback* source_callback) {
+  LOG(WARNING) << __FUNCTION__ << " : " << this;
+  // Inform audio source about the error and stop pulling data.
+  audio_worker_->Stop();
+  source_callback->OnError(this);
+}
+
+}  // namespace media
+}  // namespace chromecast