Peak Signal-to-Noise Ratio (PSNR) is the simplest and most widely used objective video quality evaluation method. However, traditional PSNR calculations do not take packet loss into account thus giving an inaccurate representation of the video quality. Indeed, transmission packet losses may be the cause of visible destructive distortions, which can result in a progressive quality degradation due to error propagation effects. This effect is even more visible in the mobile satellite video broadcasting scenario herein addressed. This paper proposes a novel video quality evaluation methodology, based on Y-PSNR (Luminance PSNR). This technique, called Windowed PSNR (WPSNR), allows to handle the packet loss problem and to evaluate the PSNR of the received sequence.