Do Users Always Know What’s Good For Them? Utilising Physiological Responses to Assess Media Quality

Subjective methods are widely used to determine whether audio and video quality in networked multimedia applications is sufficient. Recent findings suggest that, due to contextual factors, users often accept levels of media quality known to be below the threshold required for such tasks. Therefore, we propose the use of physiological methods to assess the user cost of different levels of media quality. Physiological responses (HR, GSR and BVP) to two levels of video quality (5 vs. 25 frames per second — fps) were measured in a study with 24 users. Results showed that there was a statistically significant effect of frame rate, in the direction that 5fps caused responses to indicate stress. However, only 16% of the users noticed the difference subjectively. We propose a 3-tier assessment method that combines task performance, user satisfaction and user cost to obtain a meaningful indication of the media quality required by users.