Check the mic volume only periodically on Mac.

webrtc/modules/audio_device/mac/audio_device_mac.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 20 matching lines @@
 {
 class EventWrapper;
 
 const uint32_t N_REC_SAMPLES_PER_SEC = 48000;
 const uint32_t N_PLAY_SAMPLES_PER_SEC = 48000;
 
 const uint32_t N_REC_CHANNELS = 1; // default is mono recording
 const uint32_t N_PLAY_CHANNELS = 2; // default is stereo playout
 const uint32_t N_DEVICE_CHANNELS = 64;
 
-const uint32_t ENGINE_REC_BUF_SIZE_IN_SAMPLES = (N_REC_SAMPLES_PER_SEC / 100);
-const uint32_t ENGINE_PLAY_BUF_SIZE_IN_SAMPLES = (N_PLAY_SAMPLES_PER_SEC / 100);
+const int kBufferSizeMs = 10;
+
+const uint32_t ENGINE_REC_BUF_SIZE_IN_SAMPLES =
+    N_REC_SAMPLES_PER_SEC * kBufferSizeMs / 1000;
+const uint32_t ENGINE_PLAY_BUF_SIZE_IN_SAMPLES =
+    N_PLAY_SAMPLES_PER_SEC * kBufferSizeMs / 1000;
 
 const int N_BLOCKS_IO = 2;
 const int N_BUFFERS_IN = 2;  // Must be at least N_BLOCKS_IO.
 const int N_BUFFERS_OUT = 3;  // Must be at least N_BLOCKS_IO.
 
-const uint32_t TIMER_PERIOD_MS = (2 * 10 * N_BLOCKS_IO * 1000000);
+const uint32_t TIMER_PERIOD_MS = 2 * 10 * N_BLOCKS_IO * 1000000;
 
 const uint32_t REC_BUF_SIZE_IN_SAMPLES =
     ENGINE_REC_BUF_SIZE_IN_SAMPLES * N_DEVICE_CHANNELS * N_BUFFERS_IN;
 const uint32_t PLAY_BUF_SIZE_IN_SAMPLES =
     ENGINE_PLAY_BUF_SIZE_IN_SAMPLES * N_PLAY_CHANNELS * N_BUFFERS_OUT;
 
+const int kGetMicVolumeIntervalMs = 1000;
+
 class AudioDeviceMac: public AudioDeviceGeneric
 {
 public:
     AudioDeviceMac(const int32_t id);
     ~AudioDeviceMac();
 
     // Retrieve the currently utilized audio layer
     virtual int32_t
         ActiveAudioLayer(AudioDeviceModule::AudioLayer& audioLayer) const;
 
@@ skipping 300 matching lines @@
 
     semaphore_t _renderSemaphore;
     semaphore_t _captureSemaphore;
 
     int _captureBufSizeSamples;
     int _renderBufSizeSamples;
 
     // Typing detection
     // 0x5c is key "9", after that comes function keys.
     bool prev_key_state_[0x5d];
+
+    int get_mic_volume_counter_ms_;
 };
 
 }  // namespace webrtc
 
 #endif  // MODULES_AUDIO_DEVICE_MAIN_SOURCE_MAC_AUDIO_DEVICE_MAC_H_