Upstream: Media implementation for Android.

media/audio/android/audio_track_output_android.cc

+// Copyright (c) 2011 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_android.h"
+
+#include "base/android/jni_android.h"
+#include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/time.h"
+
+using base::android::AttachCurrentThread;
+using base::android::CheckException;
+
+static const int kTimerIntervalInMilliseconds = 50;
+
+class AudioTrackOutputStream::StreamBuffer {
+ public:
+  explicit StreamBuffer(uint32 buffer_size);
+
+  uint32 ReadStream(uint8* dest, uint32 max_size);
+  void ResetBuffer(uint32 data_size);
+  uint8* GetWritableBuffer();
+  const uint8* ReadBuffer();
+  void AdvancePosition(uint32 advance);
+
+  uint32 buffer_size() { return buffer_size_; }
+  uint32 data_len() { return data_size_ - current_; }
+
+ private:
+  scoped_array<uint8> buffer_;
+  uint32 buffer_size_;
+  uint32 data_size_;
+  uint32 current_;
+
+  DISALLOW_COPY_AND_ASSIGN(StreamBuffer);
+};
+
+AudioTrackOutputStream::StreamBuffer::StreamBuffer(uint32 buffer_size)
+    : buffer_(new uint8[buffer_size]),
+      buffer_size_(buffer_size),
+      data_size_(0),
+      current_(0) {
+}
+
+uint32 AudioTrackOutputStream::StreamBuffer::ReadStream(uint8* dest,
+                                                        uint32 max_size) {
+  uint32 copy_size = data_len() < max_size ? data_len() : max_size;
+  memcpy(dest, buffer_.get() + current_, copy_size);
+  current_ += copy_size;
+  return copy_size;
+}
+
+void AudioTrackOutputStream::StreamBuffer::ResetBuffer(uint32 data_size) {
+  CHECK_LE(data_size, buffer_size_);
+  data_size_ = data_size;
+  current_ = 0;
+}
+
+uint8* AudioTrackOutputStream::StreamBuffer::GetWritableBuffer() {
+  return buffer_.get();
+}
+
+const uint8* AudioTrackOutputStream::StreamBuffer::ReadBuffer() {
+  return buffer_.get() + current_;
+}
+
+void AudioTrackOutputStream::StreamBuffer::AdvancePosition(uint32 advance) {
+  current_ += advance;
+  CHECK(current_ <= data_size_);
+}
+
+AudioTrackOutputStream::AudioTrackOutputStream(const AudioParameters& params)
+    : source_callback_(NULL),
+      params_(params.format,
+              params.sample_rate,
+              params.bits_per_sample,
+              params.samples_per_packet,
+              params.channels),
+      status_(IDLE),
+      volume_(0),
+      buffer_size_(0),
+      j_class_(NULL),
+      j_audio_track_(NULL) {
+  data_buffer_.reset(
+      new AudioTrackOutputStream::StreamBuffer(params.GetPacketSize()));
+}
+
+AudioTrackOutputStream::~AudioTrackOutputStream() {
+  Close();
+
+  if (j_class_ && j_audio_track_) {
+    JNIEnv* env = AttachCurrentThread();
+    CHECK(env);
+    env->DeleteGlobalRef(j_audio_track_);
+    j_audio_track_ = NULL;
+    env->DeleteGlobalRef(j_class_);
+    j_class_ = NULL;
+  }
+}
+
+bool AudioTrackOutputStream::Open() {
+  if (!params_.IsValid())
+    return false;
+
+  if (status_ == OPENED)
+    return true;
+  else if (status_ != IDLE)
+    return false;
+
+  JNIEnv* env = AttachCurrentThread();
+  CHECK(env);
+
+  jclass cls = env->FindClass("android/media/AudioTrack");
+  CHECK(cls);
+  j_class_ = static_cast<jclass>(env->NewGlobalRef(cls));
+  env->DeleteLocalRef(cls);
+
+  jint channels;
+  if (params_.channels == 1)
+    channels = GetStaticIntField("AudioFormat", "CHANNEL_OUT_MONO");
+  else if (params_.channels == 2)
+    channels = GetStaticIntField("AudioFormat", "CHANNEL_OUT_STEREO");
+  else if (params_.channels == 4)
+    channels = GetStaticIntField("AudioFormat", "CHANNEL_OUT_QUAD");
+  else
+    return false;
+
+  jint bits_per_sample;
+  if (params_.bits_per_sample == 16)
+    bits_per_sample = GetStaticIntField("AudioFormat", "ENCODING_PCM_16BIT");
+  else if (params_.bits_per_sample == 8)
+    bits_per_sample = GetStaticIntField("AudioFormat", "ENCODING_PCM_8BIT");
+  else
+    return false;
+
+  jmethodID min_method = env->GetStaticMethodID(j_class_, "getMinBufferSize",
+                                                "(III)I");
+  CHECK(min_method);
+
+  int min_buffer_size = env->CallStaticIntMethod(
+      j_class_, min_method, static_cast<jint>(params_.sample_rate),
+      channels, bits_per_sample);
+
+  if (params_.GetPacketSize() < min_buffer_size)
+    return false;
+  buffer_size_ = params_.GetPacketSize();
+
+  jmethodID constructor = env->GetMethodID(j_class_, "<init>", "(IIIIII)V");
+  CHECK(constructor);
+
+  jobject tmp = env->NewObject(
+      j_class_, constructor,
+      GetStaticIntField("AudioManager", "STREAM_MUSIC"),
+      static_cast<jint>(params_.sample_rate), channels, bits_per_sample,
+      static_cast<jint>(buffer_size_),
+      GetStaticIntField("AudioTrack", "MODE_STREAM"));
+
+  CHECK(tmp);
+  j_audio_track_ = env->NewGlobalRef(tmp);
+  env->DeleteLocalRef(tmp);
+
+  status_ = OPENED;
+  return true;
+}
+
+void AudioTrackOutputStream::Close() {
+  if (!j_audio_track_)
+    return;
+
+  Stop();
+  CallVoidMethod("flush");
+  status_ = INVALID;
+}
+
+void AudioTrackOutputStream::Start(AudioSourceCallback* callback) {
+  if (status_ != OPENED)
+    return;
+  if (!j_audio_track_)
+    return;
+
+  source_callback_ = callback;
+  data_buffer_->ResetBuffer(0);
+
+  FillAudioBufferTask();
+  CallVoidMethod("play");
+  status_ = PLAYING;
+
+  timer_.Start(
+      FROM_HERE,
+      base::TimeDelta::FromMilliseconds(kTimerIntervalInMilliseconds),
+      this, &AudioTrackOutputStream::FillAudioBufferTask);
+}
+
+void AudioTrackOutputStream::Stop() {
+  if (!j_audio_track_)
+    return;
+
+  if (status_ == PLAYING) {
+    timer_.Stop();
+    CallVoidMethod("stop");
+    status_ = OPENED;
+  }
+}
+
+void AudioTrackOutputStream::SetVolume(double volume) {
+  volume_ = volume;
+
+  if (!j_audio_track_)
+    return;
+
+  JNIEnv* env = AttachCurrentThread();
+  CHECK(env);
+
+  jmethodID method = env->GetMethodID(j_class_, "setStereoVolume", "(FF)I");
+  CHECK(method);
+  env->CallIntMethod(j_audio_track_, method, static_cast<jfloat>(volume),
+                     static_cast<jfloat>(volume));
+  CheckException(env);
+}
+
+void AudioTrackOutputStream::GetVolume(double* volume) {
+  if (volume)
+    *volume = volume_;
+}
+
+// static
+AudioOutputStream* AudioTrackOutputStream::MakeStream(
+    const AudioParameters& params) {
+  if (params.IsValid())
+    return new AudioTrackOutputStream(params);
+
+  return NULL;
+}
+
+void AudioTrackOutputStream::CallVoidMethod(std::string method_name) {
+  JNIEnv* env = AttachCurrentThread();
+  CHECK(env);
+
+  jmethodID method = env->GetMethodID(j_class_, method_name.c_str(), "()V");
+  CHECK(method);
+  env->CallVoidMethod(j_audio_track_, method);
+  CheckException(env);
+}
+
+jint AudioTrackOutputStream::GetStaticIntField(std::string class_name,
+                                               std::string field_name) {
+  JNIEnv* env = AttachCurrentThread();
+  CHECK(env);
+
+  class_name.insert(0, "android/media/");
+  jclass cls = env->FindClass(class_name.c_str());
+  CHECK(cls);
+
+  jfieldID field = env->GetStaticFieldID(cls, field_name.c_str(), "I");
+  CHECK(field);
+  jint int_field = env->GetStaticIntField(cls, field);
+  env->DeleteLocalRef(cls);
+  return int_field;
+}
+
+void AudioTrackOutputStream::FillAudioBufferTask() {
+  if (status_ != PLAYING)
+    return;
+
+  JNIEnv* env = AttachCurrentThread();
+  CHECK(env);
+  jmethodID method = env->GetMethodID(j_class_, "getPlaybackHeadPosition",
+                                      "()I");
+  CHECK(method);
+
+  int64 position = env->CallIntMethod(j_audio_track_, method);
+  CheckException(env);
+
+  // Calculate how many bytes we can fill in.
+  position *= params_.sample_rate * params_.bits_per_sample *
+      params_.channels / 8;
+  position %= buffer_size_;
+
+  int need_buffer = static_cast<int>(buffer_size_ - position);
+  CHECK(need_buffer >= 0 && need_buffer <= buffer_size_);
+
+  if (!need_buffer)
+    return;
+
+  // Fill the internal buffer first.
+  if (!data_buffer_->data_len()) {
+    uint32 src_data_size = source_callback_->OnMoreData(
+        this,
+        data_buffer_->GetWritableBuffer(),
+        data_buffer_->buffer_size(),
+        AudioBuffersState());
+    data_buffer_->ResetBuffer(src_data_size);
+  }
+  need_buffer = std::min(need_buffer,
+                         static_cast<int>(data_buffer_->data_len()));
+
+  // Prepare a Java array that contains the samples.
+  jbyteArray buf = env->NewByteArray(need_buffer);
+  env->SetByteArrayRegion(
+      buf, 0, need_buffer,
+      reinterpret_cast<const jbyte*>(data_buffer_->ReadBuffer()));
+  data_buffer_->AdvancePosition(need_buffer);
+
+  // Invoke method to submit samples.
+  method = env->GetMethodID(j_class_, "write", "([BII)I");
+  env->CallIntMethod(j_audio_track_, method, buf, static_cast<jint>(0),
+                     static_cast<jint>(need_buffer));
+  CheckException(env);
+  env->DeleteLocalRef(buf);
+}