libavdevice/v4l2.c:537: error: Uninitialized Value
  The value read from fps.num was never initialized.

libavdevice/v4l2.c:537:13: 
535.         if (fps.num != tpf->denominator ||
536.             fps.den != tpf->numerator) {
537.             av_log(s1, AV_LOG_INFO,
                 ^
538.                    "The driver changed the time per frame from %d/%d to %d/%d\n",
539.                    fps.den, fps.num,
