Adds support for OpenSL ES based audio capture on Android

webrtc/modules/audio_device/android/opensles_player.cc

Index: webrtc/modules/audio_device/android/opensles_player.cc
diff --git a/webrtc/modules/audio_device/android/opensles_player.cc b/webrtc/modules/audio_device/android/opensles_player.cc
index b3ad64e424627f6f1b3580ecc0b5f6e8dbbd9df9..a63b8c1257acec6fc2eda9b66fdf124bd20b71ee 100644
--- a/webrtc/modules/audio_device/android/opensles_player.cc
+++ b/webrtc/modules/audio_device/android/opensles_player.cc
@@ -44,7 +44,6 @@ OpenSLESPlayer::OpenSLESPlayer(AudioManager* audio_manager)
       audio_device_buffer_(nullptr),
       initialized_(false),
       playing_(false),
-      bytes_per_buffer_(0),
       buffer_index_(0),
       engine_(nullptr),
       player_(nullptr),
@@ -94,11 +93,13 @@ int OpenSLESPlayer::InitPlayout() {
   RTC_DCHECK(thread_checker_.CalledOnValidThread());
   RTC_DCHECK(!initialized_);
   RTC_DCHECK(!playing_);
-  ObtainEngineInterface();
+  if (!ObtainEngineInterface()) {
+    ALOGE("Failed to obtain SL Engine interface");
+    return -1;
+  }
   CreateMix();
   initialized_ = true;
   buffer_index_ = 0;
-  last_play_time_ = rtc::Time();
   return 0;
 }
 
@@ -107,6 +108,9 @@ int OpenSLESPlayer::StartPlayout() {
   RTC_DCHECK(thread_checker_.CalledOnValidThread());
   RTC_DCHECK(initialized_);
   RTC_DCHECK(!playing_);
+  if (fine_audio_buffer_) {
+    fine_audio_buffer_->ResetPlayout();
+  }
   // The number of lower latency audio players is limited, hence we create the
   // audio player in Start() and destroy it in Stop().
   CreateAudioPlayer();
@@ -114,6 +118,7 @@ int OpenSLESPlayer::StartPlayout() {
   // starts when mode is later changed to SL_PLAYSTATE_PLAYING.
   // TODO(henrika): we can save some delay by only making one call to
   // EnqueuePlayoutData. Most likely not worth the risk of adding a glitch.
+  last_play_time_ = rtc::Time();
   for (int i = 0; i < kNumOfOpenSLESBuffers; ++i) {
     EnqueuePlayoutData();
   }
@@ -187,77 +192,29 @@ void OpenSLESPlayer::AttachAudioBuffer(AudioDeviceBuffer* audioBuffer) {
   AllocateDataBuffers();
 }
 
-SLDataFormat_PCM OpenSLESPlayer::CreatePCMConfiguration(
-    size_t channels,
-    int sample_rate,
-    size_t bits_per_sample) {
-  ALOGD("CreatePCMConfiguration");
-  RTC_CHECK_EQ(bits_per_sample, SL_PCMSAMPLEFORMAT_FIXED_16);
-  SLDataFormat_PCM format;
-  format.formatType = SL_DATAFORMAT_PCM;
-  format.numChannels = static_cast<SLuint32>(channels);
-  // Note that, the unit of sample rate is actually in milliHertz and not Hertz.
-  switch (sample_rate) {
-    case 8000:
-      format.samplesPerSec = SL_SAMPLINGRATE_8;
-      break;
-    case 16000:
-      format.samplesPerSec = SL_SAMPLINGRATE_16;
-      break;
-    case 22050:
-      format.samplesPerSec = SL_SAMPLINGRATE_22_05;
-      break;
-    case 32000:
-      format.samplesPerSec = SL_SAMPLINGRATE_32;
-      break;
-    case 44100:
-      format.samplesPerSec = SL_SAMPLINGRATE_44_1;
-      break;
-    case 48000:
-      format.samplesPerSec = SL_SAMPLINGRATE_48;
-      break;
-    default:
-      RTC_CHECK(false) << "Unsupported sample rate: " << sample_rate;
-  }
-  format.bitsPerSample = SL_PCMSAMPLEFORMAT_FIXED_16;
-  format.containerSize = SL_PCMSAMPLEFORMAT_FIXED_16;
-  format.endianness = SL_BYTEORDER_LITTLEENDIAN;
-  if (format.numChannels == 1)
-    format.channelMask = SL_SPEAKER_FRONT_CENTER;
-  else if (format.numChannels == 2)
-    format.channelMask = SL_SPEAKER_FRONT_LEFT | SL_SPEAKER_FRONT_RIGHT;
-  else
-    RTC_CHECK(false) << "Unsupported number of channels: "
-                     << format.numChannels;
-  return format;
-}
-
 void OpenSLESPlayer::AllocateDataBuffers() {
   ALOGD("AllocateDataBuffers");
   RTC_DCHECK(thread_checker_.CalledOnValidThread());
   RTC_DCHECK(!simple_buffer_queue_);
   RTC_CHECK(audio_device_buffer_);
-  // Don't use the lowest possible size as native buffer size. Instead,
-  // use 10ms to better match the frame size that WebRTC uses. It will result
-  // in a reduced risk for audio glitches and also in a more "clean" sequence
-  // of callbacks from the OpenSL ES thread in to WebRTC when asking for audio
-  // to render.
-  ALOGD("lowest possible buffer size: %" PRIuS,
-      audio_parameters_.GetBytesPerBuffer());
-  bytes_per_buffer_ = audio_parameters_.GetBytesPerFrame() *
-      audio_parameters_.frames_per_10ms_buffer();
-  RTC_DCHECK_GE(bytes_per_buffer_, audio_parameters_.GetBytesPerBuffer());
-  ALOGD("native buffer size: %" PRIuS, bytes_per_buffer_);
   // Create a modified audio buffer class which allows us to ask for any number
   // of samples (and not only multiple of 10ms) to match the native OpenSL ES
-  // buffer size.
-  fine_buffer_.reset(new FineAudioBuffer(audio_device_buffer_,
-                                         bytes_per_buffer_,
-                                         audio_parameters_.sample_rate()));
+  // buffer size. The native buffer size corresponds to the
+  // PROPERTY_OUTPUT_FRAMES_PER_BUFFER property which is the number of audio
+  // frames that the HAL (Hardware Abstraction Layer) buffer can hold. It is
+  // recommended to construct audio buffers so that they contain an exact
+  // multiple of this number. If so, callbacks will occur at regular intervals,
+  // which reduces jitter.
+  ALOGD("native buffer size: %" PRIuS, audio_parameters_.GetBytesPerBuffer());
+  ALOGD("native buffer size in ms: %.2f",
+        audio_parameters_.GetBufferSizeInMilliseconds());
+  fine_audio_buffer_.reset(new FineAudioBuffer(
+      audio_device_buffer_, audio_parameters_.GetBytesPerBuffer(),
+      audio_parameters_.sample_rate()));
   // Each buffer must be of this size to avoid unnecessary memcpy while caching
   // data between successive callbacks.
   const size_t required_buffer_size =
-      fine_buffer_->RequiredPlayoutBufferSizeBytes();
+      fine_audio_buffer_->RequiredPlayoutBufferSizeBytes();
   ALOGD("required buffer size: %" PRIuS, required_buffer_size);
   for (int i = 0; i < kNumOfOpenSLESBuffers; ++i) {
     audio_buffers_[i].reset(new SLint8[required_buffer_size]);
@@ -267,7 +224,8 @@ void OpenSLESPlayer::AllocateDataBuffers() {
 bool OpenSLESPlayer::ObtainEngineInterface() {
   ALOGD("ObtainEngineInterface");
   RTC_DCHECK(thread_checker_.CalledOnValidThread());
-  RTC_DCHECK(!engine_);
+  if (engine_)
+    return true;
   // Get access to (or create if not already existing) the global OpenSL Engine
   // object.
   SLObjectItf engine_object = audio_manager_->GetOpenSLEngine();
@@ -395,6 +353,8 @@ void OpenSLESPlayer::DestroyAudioPlayer() {
   RTC_DCHECK(thread_checker_.CalledOnValidThread());
   if (!player_object_.Get())
     return;
+  (*simple_buffer_queue_)
+      ->RegisterCallback(simple_buffer_queue_, nullptr, nullptr);
   player_object_.Reset();
   player_ = nullptr;
   simple_buffer_queue_ = nullptr;
@@ -422,10 +382,10 @@ void OpenSLESPlayer::FillBufferQueue() {
 void OpenSLESPlayer::EnqueuePlayoutData() {
   // Check delta time between two successive callbacks and provide a warning
   // if it becomes very large.
-  // TODO(henrika): using 100ms as upper limit but this value is rather random.
+  // TODO(henrika): using 150ms as upper limit but this value is rather random.
   const uint32_t current_time = rtc::Time();
   const uint32_t diff = current_time - last_play_time_;
-  if (diff > 100) {
+  if (diff > 150) {
     ALOGW("Bad OpenSL ES playout timing, dT=%u [ms]", diff);
   }
   last_play_time_ = current_time;
@@ -433,11 +393,11 @@ void OpenSLESPlayer::EnqueuePlayoutData() {
   // to adjust for differences in buffer size between WebRTC (10ms) and native
   // OpenSL ES.
   SLint8* audio_ptr = audio_buffers_[buffer_index_].get();
-  fine_buffer_->GetPlayoutData(audio_ptr);
+  fine_audio_buffer_->GetPlayoutData(audio_ptr);
   // Enqueue the decoded audio buffer for playback.
-  SLresult err =
-      (*simple_buffer_queue_)
-          ->Enqueue(simple_buffer_queue_, audio_ptr, bytes_per_buffer_);
+  SLresult err = (*simple_buffer_queue_)
+                     ->Enqueue(simple_buffer_queue_, audio_ptr,
+                               audio_parameters_.GetBytesPerBuffer());
   if (SL_RESULT_SUCCESS != err) {
     ALOGE("Enqueue failed: %d", err);
   }