Adding input and output audio backend to Android.

media/audio/android/opensles_output.cc

+// Copyright (c) 2012 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/opensles_output.h"
+
+#include "base/logging.h"
+#include "media/audio/audio_util.h"
+#include "media/audio/android/audio_manager_android.h"
+
+OpenSLESOutputStream::OpenSLESOutputStream(AudioManagerAndroid* manager,
+                                           const AudioParameters& params)
+    : audio_manager_(manager),
+      callback_(NULL),
+      player_(NULL),
+      simple_buffer_queue_(NULL),
+      active_queue_(0),
+      buffer_size_bytes_(0),
+      started_(false),
+      volume_(1.0) {
+  format_.formatType = SL_DATAFORMAT_PCM;
+  format_.numChannels = static_cast<SLuint32>(params.channels());
+  // Provides sampling rate in milliHertz to OpenSLES.
+  format_.samplesPerSec = static_cast<SLuint32>(params.sample_rate() * 1000);
+  format_.bitsPerSample = params.bits_per_sample();
+  format_.containerSize = params.bits_per_sample();
+  format_.channelMask = SL_SPEAKER_FRONT_CENTER;
+  format_.endianness = SL_BYTEORDER_LITTLEENDIAN;
+
+  buffer_size_bytes_ = params.GetBytesPerBuffer();
+
+  for (int i = 0; i < kNumOfQueuesInBuffer; ++i) {
+    audio_data_[i] = new uint8[buffer_size_bytes_];
+  }
+}
+
+OpenSLESOutputStream::~OpenSLESOutputStream() {
+  DCHECK(!engine_object_.Get());
+  DCHECK(!player_object_.Get());
+  DCHECK(!output_mixer_.Get());
+  DCHECK(!player_);
+  DCHECK(!simple_buffer_queue_);
+  for (int i = 0; i < kNumOfQueuesInBuffer; ++i)
+    delete [] audio_data_[i];
+}
+
+bool OpenSLESOutputStream::Open() {
+  if (engine_object_.Get())
+    return false;
+
+  return CreatePlayer();
+}
+
+void OpenSLESOutputStream::Start(AudioSourceCallback* callback) {
+  DCHECK(callback);
+  DCHECK(player_);
+  DCHECK(simple_buffer_queue_);
+  if (started_)
+    return;
+
+  // Enable the flags before streaming.
+  callback_ = callback;
+  active_queue_ = 0;
+  started_ = true;
+
+  // Avoid start-up glitches by filling up one buffer queue before starting
+  // the stream.
+  FillBufferQueue();
+
+  // Start streaming data by setting the play state to |SL_PLAYSTATE_PLAYING|.
+  SLresult err = (*player_)->SetPlayState(player_, SL_PLAYSTATE_PLAYING);
+  DCHECK_EQ(SL_RESULT_SUCCESS, err);
+  if (SL_RESULT_SUCCESS != err) {
+    DLOG(WARNING) << "SetPlayState() failed to start playing";
+  }
+}
+
+void OpenSLESOutputStream::Stop() {
+  if (!started_)
+    return;
+
+  started_ = false;
+  // Stop playing by setting the play state to |SL_PLAYSTATE_STOPPED|.
+  SLresult err = (*player_)->SetPlayState(player_, SL_PLAYSTATE_STOPPED);
+  DLOG_IF(WARNING, SL_RESULT_SUCCESS != err) << "SetPlayState() failed to "
+                                             << "set the state to stop";
+
+
+  // Clear the buffer queue so that the old data won't be played when
+  // resuming playing.
+  err = (*simple_buffer_queue_)->Clear(simple_buffer_queue_);
+  DLOG_IF(WARNING, SL_RESULT_SUCCESS != err) << "Clear() failed to "
+                                             << "clear the buffer queue";
+}
+
+void OpenSLESOutputStream::Close() {
+  // Stop the stream if it is still playing.
+  Stop();
+
+  // Explicitly free the player objects and invalidate their associated
+  // interfaces. They have to be done in the correct order.
+  output_mixer_.Reset();
+  player_object_.Reset();
+  engine_object_.Reset();
+  simple_buffer_queue_ = NULL;
+  player_ = NULL;
+
+  audio_manager_->ReleaseOutputStream(this);
+}
+
+void OpenSLESOutputStream::SetVolume(double volume) {
+  float volume_float = static_cast<float>(volume);
+  if (volume_float < 0.0f || volume_float > 1.0f) {
+    return;
+  }
+  volume_ = volume_float;
+}
+
+void OpenSLESOutputStream::GetVolume(double* volume) {
+  *volume = static_cast<double>(volume_);
+}
+
+bool OpenSLESOutputStream::CreatePlayer() {
+  // Initializes the engine object with specific option. After working with the
+  // object, we need to free the object and its resources.
+  SLEngineOption option[] = {
+    { SL_ENGINEOPTION_THREADSAFE, static_cast<SLuint32>(SL_BOOLEAN_TRUE) }
+  };
+  SLresult err = slCreateEngine(engine_object_.Receive(), 1, option, 0,
+                                NULL, NULL);
+  DCHECK_EQ(SL_RESULT_SUCCESS, err);
+  if (SL_RESULT_SUCCESS != err)
+    return false;
+
+  // Realize the SL engine object in synchronous mode.
+  err = engine_object_->Realize(engine_object_.Get(), SL_BOOLEAN_FALSE);
+  DCHECK_EQ(SL_RESULT_SUCCESS, err);
+  if (SL_RESULT_SUCCESS != err)
+    return false;
+
+  // Get the SL engine interface which is implicit.
+  SLEngineItf engine;
+  err = engine_object_->GetInterface(engine_object_.Get(),
+                                     SL_IID_ENGINE,
+                                     &engine);
+  DCHECK_EQ(SL_RESULT_SUCCESS, err);
+  if (SL_RESULT_SUCCESS != err)
+    return false;
+
+  // Create ouput mixer object to be used by the player.
+  // TODO(xians): Do we need the environmental reverb auxiliary effect?
+  err = (*engine)->CreateOutputMix(engine,
+                                   output_mixer_.Receive(),
+                                   0,
+                                   NULL,
+                                   NULL);
+  DCHECK_EQ(SL_RESULT_SUCCESS, err);
+  if (SL_RESULT_SUCCESS != err)
+    return false;
+
+  // Realizing the output mix object in synchronous mode.
+  err = output_mixer_->Realize(output_mixer_.Get(), SL_BOOLEAN_FALSE);
+  DCHECK_EQ(SL_RESULT_SUCCESS, err);
+  if (SL_RESULT_SUCCESS != err)
+    return false;
+
+  // Audio source configuration.
+  SLDataLocator_AndroidSimpleBufferQueue simple_buffer_queue = {
+    SL_DATALOCATOR_ANDROIDSIMPLEBUFFERQUEUE,
+    static_cast<SLuint32>(kNumOfQueuesInBuffer)
+  };
+  SLDataSource audio_source = { &simple_buffer_queue, &format_ };
+
+  // Audio sink configuration.
+  SLDataLocator_OutputMix locator_output_mix = {
+    SL_DATALOCATOR_OUTPUTMIX, output_mixer_.Get()
+  };
+  SLDataSink audio_sink = { &locator_output_mix, NULL };
+
+  // Create an audio player.
+  const SLuint32 number_of_interfaces = 1;
+  const SLInterfaceID interface_id[number_of_interfaces] = {
+    SL_IID_BUFFERQUEUE
+  };
+  const SLboolean interface_required[number_of_interfaces] = {
+    SL_BOOLEAN_TRUE
+  };
+  err = (*engine)->CreateAudioPlayer(engine,
+                                     player_object_.Receive(),
+                                     &audio_source,
+                                     &audio_sink,
+                                     number_of_interfaces,
+                                     interface_id,
+                                     interface_required);
+  DCHECK_EQ(SL_RESULT_SUCCESS, err);
+  if (SL_RESULT_SUCCESS != err) {
+    DLOG(ERROR) << "CreateAudioPlayer() failed with error code " << err;
+    return false;
+  }
+
+  // Realize the player object in synchronous mode.
+  err = player_object_->Realize(player_object_.Get(), SL_BOOLEAN_FALSE);
+  DCHECK_EQ(SL_RESULT_SUCCESS, err);
+  if (SL_RESULT_SUCCESS != err) {
+    DLOG(ERROR) << "Player Realize() failed with error code " << err;
+    return false;
+  }
+
+  // Get an implicit player interface.
+  err = player_object_->GetInterface(
+      player_object_.Get(), SL_IID_PLAY, &player_);
+  DCHECK_EQ(SL_RESULT_SUCCESS, err);
+  if (SL_RESULT_SUCCESS != err)
+    return false;
+
+  // Get the simple buffer queue interface.
+  err = player_object_->GetInterface(player_object_.Get(),
+                                     SL_IID_BUFFERQUEUE,
+                                     &simple_buffer_queue_);
+  DCHECK_EQ(SL_RESULT_SUCCESS, err);
+  if (SL_RESULT_SUCCESS != err)
+    return false;
+
+  // Register the input callback for the simple buffer queue.
+  // This callback will be called when the soundcard needs data.
+  err = (*simple_buffer_queue_)->RegisterCallback(simple_buffer_queue_,
+                                                  SimpleBufferQueueCallback,
+                                                  this);
+  DCHECK_EQ(SL_RESULT_SUCCESS, err);
+
+  return (SL_RESULT_SUCCESS == err);
+}
+
+void OpenSLESOutputStream::SimpleBufferQueueCallback(
+    SLAndroidSimpleBufferQueueItf buffer_queue, void* instance) {
+  OpenSLESOutputStream* stream =
+      reinterpret_cast<OpenSLESOutputStream*>(instance);
+  stream->FillBufferQueue();
+}
+
+void OpenSLESOutputStream::FillBufferQueue() {
+  if (!started_)
+    return;
+
+  // Read data from the registered client source.
+  // TODO(xians): Get an accurate delay estimation.
+  uint32 hardware_delay = buffer_size_bytes_;
+  size_t num_filled_bytes = callback_->OnMoreData(
+      this,
+      audio_data_[active_queue_],
+      buffer_size_bytes_,
+      AudioBuffersState(0, hardware_delay));
+  DCHECK(num_filled_bytes <= buffer_size_bytes_);
+
+  // Perform in-place, software-volume adjustments.
+  media::AdjustVolume(audio_data_[active_queue_],
+                      num_filled_bytes,
+                      format_.numChannels,
+                      format_.containerSize >> 3,
+                      volume_);
+
+  // Enqueue the buffer for playback.
+  SLresult err = (*simple_buffer_queue_)->Enqueue(
+      simple_buffer_queue_,
+      audio_data_[active_queue_],
+      num_filled_bytes);
+  if (SL_RESULT_SUCCESS != err)
+    HandleError(err);
+
+  active_queue_ = ++active_queue_ % kNumOfQueuesInBuffer;
+}
+
+void OpenSLESOutputStream::HandleError(SLresult error) {
+  DLOG(FATAL) << "OpenSLES error " << error;
+  if (callback_)
+    callback_->OnError(this, error);
+}