Adds volume level measurements to the AudioInputController for low-latency clients

media/audio/audio_input_controller.h

 // 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.
 
 #ifndef MEDIA_AUDIO_AUDIO_INPUT_CONTROLLER_H_
 #define MEDIA_AUDIO_AUDIO_INPUT_CONTROLLER_H_
 
 #include <string>
 #include "base/atomicops.h"
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/synchronization/lock.h"
 #include "base/synchronization/waitable_event.h"
 #include "base/threading/thread.h"
 #include "base/timer/timer.h"
 #include "media/audio/audio_io.h"
 #include "media/audio/audio_manager_base.h"
+#include "media/audio/audio_parameters.h"
+#include "media/audio/audio_power_monitor.h"
+#include "media/base/audio_bus.h"
 
 // An AudioInputController controls an AudioInputStream and records data
 // from this input stream. The two main methods are Record() and Close() and
 // they are both executed on the audio thread which is injected by the two
 // alternative factory methods, Create() or CreateLowLatency().
 //
 // All public methods of AudioInputController are non-blocking.
 //
 // Here is a state diagram for the AudioInputController:
 //
@@ skipping 36 matching lines @@
 // Closure::Run() <-----------------.
 // (closure-task)
 //
 // The audio thread itself is owned by the AudioManager that the
 // AudioInputController holds a reference to.  When performing tasks on the
 // audio thread, the controller must not add or release references to the
 // AudioManager or itself (since it in turn holds a reference to the manager).
 //
 namespace media {
 
+// Only do power monitoring for non-mobile platforms to save resources.
+#if !defined(OS_ANDROID) && !defined(OS_IOS)
+#define AUDIO_POWER_MONITORING
+#endif
+
 class UserInputMonitor;
 
 class MEDIA_EXPORT AudioInputController
     : public base::RefCountedThreadSafe<AudioInputController>,
       public AudioInputStream::AudioInputCallback {
  public:
 
   // Error codes to make native loggin more clear. These error codes are added
   // to generic error strings to provide a higher degree of details.
   // Changing these values can lead to problems when matching native debug
@@ skipping 19 matching lines @@
   // An event handler that receives events from the AudioInputController. The
   // following methods are all called on the audio thread.
   class MEDIA_EXPORT EventHandler {
    public:
     virtual void OnCreated(AudioInputController* controller) = 0;
     virtual void OnRecording(AudioInputController* controller) = 0;
     virtual void OnError(AudioInputController* controller,
                          ErrorCode error_code) = 0;
     virtual void OnData(AudioInputController* controller, const uint8* data,
                         uint32 size) = 0;
+    virtual void OnLog(AudioInputController* controller,
+                       const std::string& message) = 0;
 
    protected:
     virtual ~EventHandler() {}
   };
 
   // A synchronous writer interface used by AudioInputController for
   // synchronous writing.
   class SyncWriter {
    public:
     virtual ~SyncWriter() {}
@@ skipping 121 matching lines @@
   void DoCreate(AudioManager* audio_manager, const AudioParameters& params,
                 const std::string& device_id);
   void DoCreateForStream(AudioInputStream* stream_to_control,
                          bool enable_nodata_timer);
   void DoRecord();
   void DoClose();
   void DoReportError();
   void DoSetVolume(double volume);
   void DoSetAutomaticGainControl(bool enabled);
   void DoOnData(scoped_ptr<uint8[]> data, uint32 size);
+  void DoLogAudioLevel();
 
   // Method to check if we get recorded data after a stream was started,
   // and log the result to UMA.
   void FirstCheckForNoData();
 
   // Method which ensures that OnError() is triggered when data recording
   // times out. Called on the audio thread.
   void DoCheckForNoData();
 
   // Helper method that stops, closes, and NULL:s |*stream_|.
@@ skipping 37 matching lines @@
 
   // SyncWriter is used only in low-latency mode for synchronous writing.
   SyncWriter* sync_writer_;
 
   static Factory* factory_;
 
   double max_volume_;
 
   UserInputMonitor* user_input_monitor_;
 
+#if defined(AUDIO_POWER_MONITORING)

[no longer working on chromium, 2014/05/26 14:20:16]

I don't think you save much by excluding these members from those platfroms, I
suggest removing the AUDIO_POWER_MONITORING here and move the definition of
AUDIO_POWER_MONITORING to the implementation instead

[henrika (OOO until Aug 14), 2014/05/26 15:01:17]

I copied how it was done on the output side (in the AOC) to make it symmetric.
OK?

[henrika (OOO until Aug 14), 2014/05/27 07:46:36]

In addition, we should really do our best to simplify as much as possible for
mobile. Every byte counts.

+  // Scans audio samples from OnData() as input to compute audio levels.
+  scoped_ptr<AudioPowerMonitor> audio_level_;
+
+  // We need these to be able to feed data to the AudioPowerMonitor.
+  scoped_ptr<AudioBus> audio_bus_;
+  media::AudioParameters audio_params_;
+  base::TimeTicks last_audio_level_log_time_;
+#endif
+
   size_t prev_key_down_count_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioInputController);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_AUDIO_INPUT_CONTROLLER_H_