552: interframe interval = 1/33.44 s  avg=1/20.08  stddev=1/31.59
  539: interframe interval = 1/ 7.62 s  avg=1/20.35  stddev=1/31.93
  539: interframe interval = 1/26.36 s  avg=1/20.30  stddev=1/30.16
  540: interframe interval = 1/ 9.49 s  avg=1/20.08  stddev=1/34.37
  539: interframe interval = 1/27.71 s  avg=1/20.70  stddev=1/33.74
  539: interframe interval = 1/26.90 s  avg=1/20.74  stddev=1/31.51
  527: interframe interval = 1/49.55 s  avg=1/20.41  stddev=1/36.04
  540: interframe interval = 1/12.13 s  avg=1/20.35  stddev=1/33.87
  539: interframe interval = 1/26.74 s  avg=1/19.93  stddev=1/30.32