Avoid clicks when muting/unmuting a voe::Channel.

webrtc/voice_engine/channel.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 251 matching lines @@
 
   // VoEExternalMediaProcessing
   int RegisterExternalMediaProcessing(ProcessingTypes type,
                                       VoEMediaProcess& processObject);
   int DeRegisterExternalMediaProcessing(ProcessingTypes type);
   int SetExternalMixing(bool enabled);
 
   // VoEVolumeControl
   int GetSpeechOutputLevel(uint32_t& level) const;
   int GetSpeechOutputLevelFullRange(uint32_t& level) const;
-  int SetMute(bool enable);
-  bool Mute() const;
+  int SetInputMute(bool enable);
+  bool InputMute() const;
   int SetOutputVolumePan(float left, float right);
   int GetOutputVolumePan(float& left, float& right) const;
   int SetChannelOutputVolumeScaling(float scaling);
   int GetChannelOutputVolumeScaling(float& scaling) const;
 
   // VoENetEqStats
   int GetNetworkStatistics(NetworkStatistics& stats);
   void GetDecodingCallStatistics(AudioDecodingCallStats* stats) const;
 
   // VoEVideoSync
@@ skipping 245 matching lines @@
   Transport* _transportPtr;  // WebRtc socket or external transport
   RMSLevel rms_level_;
   std::unique_ptr<AudioProcessing> rx_audioproc_;  // far end AudioProcessing
   VoERxVadCallback* _rxVadObserverPtr;
   int32_t _oldVadDecision;
   int32_t _sendFrameType;  // Send data is voice, 1-voice, 0-otherwise
   // VoEBase
   bool _externalMixing;
   bool _mixFileWithMicrophone;
   // VoEVolumeControl
-  bool _mute;
-  float _panLeft;
-  float _panRight;
-  float _outputGain;
+  bool input_mute_ GUARDED_BY(volume_settings_critsect_);
+  bool previous_frame_muted_;  // Only accessed from PrepareEncodeAndSend().
+  float _panLeft GUARDED_BY(volume_settings_critsect_);
+  float _panRight GUARDED_BY(volume_settings_critsect_);
+  float _outputGain GUARDED_BY(volume_settings_critsect_);
   // VoeRTP_RTCP
   uint32_t _lastLocalTimeStamp;
   int8_t _lastPayloadType;
   bool _includeAudioLevelIndication;
   // VoENetwork
   AudioFrame::SpeechType _outputSpeechType;
   // VoEVideoSync
   rtc::CriticalSection video_sync_lock_;
   uint32_t _average_jitter_buffer_delay_us GUARDED_BY(video_sync_lock_);
   uint32_t _previousTimestamp;
@@ skipping 14 matching lines @@
   PacketRouter* packet_router_ = nullptr;
   std::unique_ptr<TransportFeedbackProxy> feedback_observer_proxy_;
   std::unique_ptr<TransportSequenceNumberProxy> seq_num_allocator_proxy_;
   std::unique_ptr<RtpPacketSenderProxy> rtp_packet_sender_proxy_;
 };
 
 }  // namespace voe
 }  // namespace webrtc
 
 #endif  // WEBRTC_VOICE_ENGINE_CHANNEL_H_