A Prototype No-Reference Video Quality System

This paper introduces a number of innovative no-reference algorithms to assess the perceived quality of realtime analog and digital television and video streams. A prototype system is developed to locate and measure the impact of three types of impairments that commonly impair television and video signals. Analog sequences are tested for the presence of random noise. In the case of digital signals, two fundamental types of errors are of interest. The first is the blocking artifact that is so pervasive among DCT-based compression schemes such as MPEG. The second category includes errors caused by random changes to the bit stream of a signal. Of the various forms that these distortions may take on, only those that appear as "colored blocks" are detected by this system. Ideas to address the remaining issues are discussed.