Add an AudioTrack based audio output stream.

media/audio/android/audio_track_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 "media/audio/android/audio_track_output_stream.h"
+
+#include "base/bind.h"
+#include "base/bind_helpers.h"
+#include "base/logging.h"
+#include "base/single_thread_task_runner.h"
+#include "jni/AudioTrackOutputStream_jni.h"
+#include "media/audio/audio_manager_base.h"
+
+using base::android::AttachCurrentThread;
+
+namespace media {
+
+AudioTrackOutputStream::AudioTrackOutputStream(AudioManagerBase* manager,
+                                               const AudioParameters& params)
+    : params_(params),
+      audio_manager_(manager),
+      callback_(nullptr),
+      audio_bus_(AudioBus::Create(params_)),
+      volume_(1.0) {
+  audio_bus_->Zero();
+}
+
+AudioTrackOutputStream::~AudioTrackOutputStream() {
+  DCHECK(!callback_);
+}
+
+bool AudioTrackOutputStream::Open() {
+  DCHECK(audio_manager_->GetTaskRunner()->BelongsToCurrentThread());
+  JNIEnv* env = AttachCurrentThread();
+  j_audio_output_stream_.Reset(Java_AudioTrackOutputStream_create(env));
+  return Java_AudioTrackOutputStream_open(
+      env, j_audio_output_stream_.obj(), params_.channels(),
+      params_.sample_rate(), 4, params_.frames_per_buffer());
+}
+
+void AudioTrackOutputStream::Start(AudioSourceCallback* callback) {
+  DCHECK(audio_manager_->GetTaskRunner()->BelongsToCurrentThread());
+  callback_ = callback;
+  Java_AudioTrackOutputStream_start(AttachCurrentThread(),
+                                    j_audio_output_stream_.obj(),
+                                    reinterpret_cast<intptr_t>(this));
+}
+
+void AudioTrackOutputStream::Stop() {
+  DCHECK(audio_manager_->GetTaskRunner()->BelongsToCurrentThread());
+  Java_AudioTrackOutputStream_stop(AttachCurrentThread(),
+                                   j_audio_output_stream_.obj());
+  callback_ = nullptr;
+}
+
+void AudioTrackOutputStream::Close() {
+  DCHECK(!callback_);
+  DCHECK(audio_manager_->GetTaskRunner()->BelongsToCurrentThread());
+  Java_AudioTrackOutputStream_close(AttachCurrentThread(),
+                                    j_audio_output_stream_.obj());
+  audio_manager_->ReleaseOutputStream(this);
+}
+
+void AudioTrackOutputStream::SetVolume(double volume) {
+  // Track |volume_| since AudioTrack uses a scaled value.
+  volume_ = volume;
+  Java_AudioTrackOutputStream_setVolume(AttachCurrentThread(),
+                                        j_audio_output_stream_.obj(), volume);
+};
+
+void AudioTrackOutputStream::GetVolume(double* volume) {
+  *volume = volume_;
+};
+
+// AudioOutputStream::SourceCallback implementation methods called from Java.
+void AudioTrackOutputStream::OnMoreData(JNIEnv* env,
+                                        jobject obj,
+                                        jobject audio_data,
+                                        int delay_in_frames) {
+  if (!callback_)
+    return;
+
+  callback_->OnMoreData(audio_bus_.get(),
+                        delay_in_frames * params_.GetBytesPerFrame());
+  float* native_bus =
+      reinterpret_cast<float*>(env->GetDirectBufferAddress(audio_data));
+
+  for (int ch = 0; ch < audio_bus_->channels(); ++ch) {
+    const float* source_data = audio_bus_->channel(ch);
+    for (int i = 0, offset = ch; i < audio_bus_->frames();
+         ++i, offset += audio_bus_->channels()) {
+      native_bus[offset] = source_data[i];
+    }
+  }
+}
+
+void AudioTrackOutputStream::OnError(JNIEnv* env, jobject obj) {
+  DCHECK(callback_);
+  callback_->OnError(this);
+}
+
+// static
+bool AudioTrackOutputStream::RegisterAudioTrackOutputStream(JNIEnv* env) {
+  return RegisterNativesImpl(env);
+}
+
+}  // namespace media