539: interframe interval = 1/32.20 s  avg=1/30.82  stddev=1/114.14

  539: interframe interval = 1/50.98 s  avg=1/30.73  stddev=1/128.25

  539: interframe interval = 1/32.75 s  avg=1/30.55  stddev=1/106.21

  527: interframe interval = 1/32.77 s  avg=1/30.39  stddev=1/95.46