text: // Copyright (c) 2017, The Regents of the University of California
  // All rights reserved.
  //
  // Redistribution and use in source and binary forms, with or without
  // modification, are permitted provided that the following conditions are met:
  // * Redistributions of source code must retain the above copyright
  //   notice, this list of conditions and the following disclaimer.
  // * Redistributions in binary form must reproduce the above copyright
  //   notice, this list of conditions and the following disclaimer in the
  //   documentation and/or other materials provided with the distribution.
  // * Neither the name of the University of California nor the
  //   names of its contributors may be used to endorse or promote products
  //   derived from this software without specific prior written permission.
  //
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  // ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
  // BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  // CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  // SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  // INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  // CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  // ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  // POSSIBILITY OF SUCH DAMAGE.
  
  #include <cmath>
  
  #include "cogrob/cloud/speech/record_audio.h"
  #include "third_party/gflags.h"
  #include "third_party/glog.h"
  #include "util/simple_thread_safe_queue.h"
  
  namespace speech = ::cogrob::cloud::speech;
  using speech::AudioSample;
  
  int main(int argc, char *argv[]) {
    google::InitGoogleLogging(argv[0]);
    google::LogToStderr();
    gflags::SetUsageMessage("PrintRMS utility for testing microphone.");
    gflags::SetVersionString("1.0.0");
    gflags::ParseCommandLineFlags(&argc, &argv, true);
  
    util::SimpleThreadSafeQueue<std::unique_ptr<AudioSample>> audio_queue;
    speech::AudioRecorder recorder(&audio_queue);
    while (true) {
      std::unique_ptr<AudioSample> sample = std::move(audio_queue.blocking_pop());
      double square_sum = 0;
      for (size_t i = 0; i < sample->size(); i += 2) {
        int s = (static_cast<int8_t>((*sample)[i + 1])) << 8 | (*sample)[i];
        square_sum += s * s;
      }
      double rms = std::sqrt(square_sum / (sample->size() / 2));
      LOG(INFO) << "RMS: " << rms;
    }
  }
  