Surface the noise estimate of the NS to be used by other components

webrtc/modules/audio_processing/include/audio_processing.h

 /*
  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 897 matching lines @@
   };
 
   virtual int set_level(Level level) = 0;
   virtual Level level() const = 0;
 
   // Returns the internally computed prior speech probability of current frame
   // averaged over output channels. This is not supported in fixed point, for
   // which |kUnsupportedFunctionError| is returned.
   virtual float speech_probability() const = 0;
 
+  // Returns the noise estimate per frequency bin of current chunk averaged

[turaj, 2016/02/05 01:47:58]

Isn't it some sort of noise power averaged over some time interval. The comment
says "current chunk" sounds like instantaneous power, is it really it?

[aluebs-webrtc, 2016/02/06 00:12:27]

No, it actually estimates it smoothly over time. Good point, I removed the
"current chunk" comment.

+  // over all channels.
+  virtual const std::vector<float>& noise_estimate() = 0;
+
  protected:
   virtual ~NoiseSuppression() {}
 };
 
 // The voice activity detection (VAD) component analyzes the stream to
 // determine if voice is present. A facility is also provided to pass in an
 // external VAD decision.
 //
 // In addition to |stream_has_voice()| the VAD decision is provided through the
 // |AudioFrame| passed to |ProcessStream()|. The |vad_activity_| member will be
@@ skipping 36 matching lines @@
   // This does not impact the size of frames passed to |ProcessStream()|.
   virtual int set_frame_size_ms(int size) = 0;
   virtual int frame_size_ms() const = 0;
 
  protected:
   virtual ~VoiceDetection() {}
 };
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_AUDIO_PROCESSING_INCLUDE_AUDIO_PROCESSING_H_