Since the development of digital video technology, due to the nature of digital video, the approach to video quality estimation has changed. Basically there are two types of metrics used to measure the objective quality of processed digital video: purely mathematically defined video quality metrics (DELTA, MSAD, MSE, SNR and PSNR) where the error is mathematically calculated as a difference between the original and processed pixel, and video quality metrics that have similar characteristics as the Human Visual System – HVS (SSIM, NQI, VQM) where the perceptual quality is considered in the overall video quality estimation. In this paper, an overview and experimental comparison of PSNR and SSIM metrics for video quality estimation is presented.