libavdevice/v4l2.c:529: error: Uninitialized Value
  The value read from fps.num was never initialized.

libavdevice/v4l2.c:529:13: 
527.         tpf->denominator = fps.num;
528.         if (ioctl(s->fd, VIDIOC_S_PARM, &streamparm) != 0) {
529.             av_log(s1, AV_LOG_ERROR,
                 ^
530.                    "ioctl set time per frame(%d/%d) failed\n",
531.                    fps.den, fps.num);
