Support floating-point audio output for Linux

media/audio/pulse/pulse_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/pulse/pulse_output.h"
 
 #include <pulse/pulseaudio.h>
 #include <stdint.h>
 
 #include "base/single_thread_task_runner.h"
 #include "base/time/time.h"
 #include "media/audio/audio_device_description.h"
 #include "media/audio/audio_manager_base.h"
 #include "media/audio/pulse/pulse_util.h"
+#include "media/base/audio_sample_types.h"
 
 namespace media {
 
 using pulse::AutoPulseLock;
 using pulse::WaitForOperationCompletion;
 
 // static, pa_stream_notify_cb
 void PulseAudioOutputStream::StreamNotifyCallback(pa_stream* s, void* p_this) {
   PulseAudioOutputStream* stream = static_cast<PulseAudioOutputStream*>(p_this);
 
@@ skipping 114 matching lines @@
 
       // Zero any unfilled data so it plays back as silence.
       if (frames_filled < audio_bus_->frames()) {
         audio_bus_->ZeroFramesPartial(
             frames_filled, audio_bus_->frames() - frames_filled);
       }
 
       // Note: If this ever changes to output raw float the data must be clipped
       // and sanitized since it may come from an untrusted source such as NaCl.
       audio_bus_->Scale(volume_);
+#if 0
       audio_bus_->ToInterleaved(
           audio_bus_->frames(), params_.bits_per_sample() / 8, buffer);
+#else
+      audio_bus_->ToInterleaved<Float32SampleTypeTraits>(
+          audio_bus_->frames(), reinterpret_cast<float*>(buffer));

[DaleCurtis, 2016/11/01 18:51:37]

is buffer allocated correctly?

+#endif
     } else {
       memset(buffer, 0, bytes_to_fill);
     }
 
     if (pa_stream_write(pa_stream_, buffer, bytes_to_fill, NULL, 0LL,
                         PA_SEEK_RELATIVE) < 0) {
       if (source_callback_) {
         source_callback_->OnError(this);
       }
     }
@@ skipping 72 matching lines @@
   volume_ = static_cast<float>(volume);
 }
 
 void PulseAudioOutputStream::GetVolume(double* volume) {
   DCHECK(thread_checker_.CalledOnValidThread());
 
   *volume = volume_;
 }
 
 }  // namespace media