Subjective video quality evaluation for multimedia applications

Abstract

Video quality can be measured using both subjective and objective assessment methods. Subjective experiments are crucially important as they constitute a benchmark for evaluating the performance of objective quality metrics. Subjective quality assessment of television pictures has received extensive attention from experts over the past decades. On the other hand, emerging applications such as PC-based video streaming and mobile video streaming require new subjective test methodologies. Although some recent studies have compared different test methodologies and procedures, most concerned television pictures. No studies for multimedia-type video really validated the repeatability and reliability of the assessment method and the experimental procedure. This paper outlines a methodology for conducting subjective evaluation of video quality for multimedia applications in a repeatable and reliable manner across different laboratories. Using video material at low-resolution, low-bit rate and low-frame rate, the same experiment was conducted by two different laboratories, i.e. test material was identical in both experiments. Laboratory set-up was different, i.e. different computers and display panels were used, and viewing distance was not fixed. Results show that quality ratings obtained in both experiments are statistically identical. This is an important validation step for the Video Quality Experts Group, which will conduct an ambitious campaign of subjective experiments using many different test laboratories.