A video apparatus for processing an input video signal in synchronization with an external reference signal is provided. The video apparatus includes a phase compensation FIFO memory and a measuring device. The phase compensation FIFO memory is configured such that the input video signal is written in synchronization with a clock demodulated from the input video signal and the video signal is read in synchronization with an internal reference clock of the apparatus generated from the external reference signal. The measuring device is configured to measure an amount of jitter/wander of the input video signal based on a calculation of a difference between data volume of the video signal obtained in the FIFO memory and a predetermined reference volume.