libavdevice/v4l2.c:526: error: Uninitialized Value
  The value read from fps.den was never initialized.

libavdevice/v4l2.c:526:9: 
524.         av_log(s1, AV_LOG_DEBUG, "Setting time per frame to %d/%d\n",
525.                fps.den, fps.num);
526.         tpf->numerator   = fps.den;
             ^
527.         tpf->denominator = fps.num;
528.         if (ioctl(s->fd, VIDIOC_S_PARM, &streamparm) != 0) {
