Enable float audio output on L+ Android devices.

media/audio/android/opensles_output.cc

Index: media/audio/android/opensles_output.cc
diff --git a/media/audio/android/opensles_output.cc b/media/audio/android/opensles_output.cc
index e6062362fad53b13538d52c5031e22e860d7d951..d8eb72ff3b332ade0f812451813aaacd58f223be 100644
--- a/media/audio/android/opensles_output.cc
+++ b/media/audio/android/opensles_output.cc
@@ -4,11 +4,13 @@
 
 #include "media/audio/android/opensles_output.h"
 
+#include "base/android/build_info.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/time/time.h"
 #include "base/trace_event/trace_event.h"
 #include "media/audio/android/audio_manager_android.h"
+#include "media/base/audio_sample_types.h"
 #include "media/base/audio_timestamp_helper.h"
 
 #define LOG_ON_FAILURE_AND_RETURN(op, ...)      \
@@ -32,15 +34,38 @@ OpenSLESOutputStream::OpenSLESOutputStream(AudioManagerAndroid* manager,
       simple_buffer_queue_(NULL),
       audio_data_(),
       active_buffer_index_(0),
-      bytes_per_frame_(params.GetBytesPerFrame()),
-      buffer_size_bytes_(params.GetBytesPerBuffer()),
       started_(false),
       muted_(false),
       volume_(1.0),
       samples_per_second_(params.sample_rate()),
+      have_float_output_(base::android::BuildInfo::GetInstance()->sdk_int() >=
+                         base::android::SDK_VERSION_LOLLIPOP),
+      bytes_per_frame_(have_float_output_ ? params.channels() * sizeof(float)
+                                          : params.GetBytesPerFrame()),
+      buffer_size_bytes_(have_float_output_
+                             ? bytes_per_frame_ * params.frames_per_buffer()
+                             : params.GetBytesPerBuffer()),
       delay_calculator_(samples_per_second_) {
   DVLOG(2) << "OpenSLESOutputStream::OpenSLESOutputStream("
            << "stream_type=" << stream_type << ")";
+
+  audio_bus_ = AudioBus::Create(params);
+
+  if (have_float_output_) {
+    float_format_.formatType = SL_ANDROID_DATAFORMAT_PCM_EX;
+    float_format_.numChannels = static_cast<SLuint32>(params.channels());
+    // Despite the name, this field is actually the sampling rate in millihertz.
+    float_format_.sampleRate =
+        static_cast<SLuint32>(samples_per_second_ * 1000);
+    float_format_.bitsPerSample = 32;
+    float_format_.containerSize = 32;
+    float_format_.endianness = SL_BYTEORDER_LITTLEENDIAN;
+    float_format_.channelMask =
+        ChannelCountToSLESChannelMask(params.channels());
+    float_format_.representation = SL_ANDROID_PCM_REPRESENTATION_FLOAT;
+    return;
+  }
+
   format_.formatType = SL_DATAFORMAT_PCM;
   format_.numChannels = static_cast<SLuint32>(params.channels());
   // Despite the name, this field is actually the sampling rate in millihertz :|
@@ -49,7 +74,6 @@ OpenSLESOutputStream::OpenSLESOutputStream(AudioManagerAndroid* manager,
   format_.containerSize = params.bits_per_sample();
   format_.endianness = SL_BYTEORDER_LITTLEENDIAN;
   format_.channelMask = ChannelCountToSLESChannelMask(params.channels());
-  audio_bus_ = AudioBus::Create(params);
 }
 
 OpenSLESOutputStream::~OpenSLESOutputStream() {
@@ -241,7 +265,11 @@ bool OpenSLESOutputStream::CreatePlayer() {
   SLDataLocator_AndroidSimpleBufferQueue simple_buffer_queue = {
       SL_DATALOCATOR_ANDROIDSIMPLEBUFFERQUEUE,
       static_cast<SLuint32>(kMaxNumOfBuffersInQueue)};
-  SLDataSource audio_source = {&simple_buffer_queue, &format_};
+  SLDataSource audio_source;
+  if (have_float_output_)
+    audio_source = {&simple_buffer_queue, &float_format_};
+  else
+    audio_source = {&simple_buffer_queue, &format_};
 
   // Audio sink configuration.
   SLDataLocator_OutputMix locator_output_mix = {SL_DATALOCATOR_OUTPUTMIX,
@@ -373,8 +401,14 @@ void OpenSLESOutputStream::FillBufferQueueNoLock() {
   // raw float, the data must be clipped and sanitized since it may come
   // from an untrusted source such as NaCl.
   audio_bus_->Scale(muted_ ? 0.0f : volume_);
-  audio_bus_->ToInterleaved(frames_filled, format_.bitsPerSample / 8,
-                            audio_data_[active_buffer_index_]);
+  if (!have_float_output_) {
+    audio_bus_->ToInterleaved(frames_filled, format_.bitsPerSample / 8,
+                              audio_data_[active_buffer_index_]);
+  } else {
+    audio_bus_->ToInterleaved<Float32SampleTypeTraits>(
+        frames_filled,
+        reinterpret_cast<float*>(audio_data_[active_buffer_index_]));
+  }
 
   delay_calculator_.AddFrames(frames_filled);
   const int num_filled_bytes = frames_filled * bytes_per_frame_;
@@ -393,9 +427,8 @@ void OpenSLESOutputStream::FillBufferQueueNoLock() {
 void OpenSLESOutputStream::SetupAudioBuffer() {
   DCHECK(thread_checker_.CalledOnValidThread());
   DCHECK(!audio_data_[0]);
-  for (int i = 0; i < kMaxNumOfBuffersInQueue; ++i) {
+  for (int i = 0; i < kMaxNumOfBuffersInQueue; ++i)
     audio_data_[i] = new uint8_t[buffer_size_bytes_];
-  }
 }
 
 void OpenSLESOutputStream::ReleaseAudioBuffer() {