Reference Algorithm for Computing Peak Signal to Noise Ratio (PSNR) of a Video Sequence with a Constant Delay
Stephen Wolf · 2009
Peak Signal to Noise Ratio (PSNR) has been used as a benchmark to evaluate new objective perceptual video quality metrics. For example, PSNR has been used as a benchmark for both the Multimedia (MM) and Reduced Reference Television (RRTV) test programs recently completed by the Video Quality Experts Group (VQEG). However, there is not currently an international Recommendation specifying exactly how to perform this critical measurement. Since the calculation of PSNR is highly dependent upon proper calculation of spatial alignment, temporal alignment, gain, and level offset between the processed video sequence and the original video sequence, one must also specify the method of performing these calibration procedures. The past two validation tests (MM and RRTV) performed by VQEG utilized the exhaustive search PSNR algorithm that is the subject of this contribution. Members of VQEG agreed to use this PSNR method as a benchmark for assessing the effectiveness of perceptual video quality metrics after extensive discussions. This PSNR calculation method has the advantage of automatically determining the highest possible PSNR value for a given video sequence over the range of spatial and temporal shifts. Only one temporal shift is allowed for all frames in the entire processed video sequence (i.e., constant delay).