The present study aimed at low motion talking head videos, the effect of dynamics in moderate motion and in high motion scenes remains open; this, of course, could also be the subject of further research.
Some of the guidelines, elaborated in this experimental study, are of absolute nature, inasmuch as they relate to characteristics of the sensory system and do not depend on features of the test equipment given by current technology; others, however, are relative inasmuch as they are constrained to the specific experimental conditions of our study; e.g., optimum size depends on the screen size. Thus, the influence of smaller and larger screens than that used in our study should be investigated, too. Most of the minimum requirements are absolute in the above mentioned sense. Compared to it, all optimum and maximum requirements are relative recommendations.
Technology develops in the field of multimedia rapidly; therefore, some of the guide-lines have to be matched with these changing conditions, too.
The focus in our study was on perceptibility issues, mainly. If ergonomically well designed human-computer interfaces are aspired, the whole information process from strimulus to response should be considered including perception, cognition, action planning and activity regulation as well as sensu-motoric control.
That means, guidelines are needed for information content design, for taskspecific multimedia information coding, for organization of information on the screen (formatting) and for navigation in the multimedia hyperspace, i.e., lexical, syntactic, semantic as well as pragmatic aspects of information exchange have to be taken into consideration.
Intemational Standards Organisation ISO ( 1998). Ergonomic requirements for office work with visual display terminals (YDTs), parts 1-17. International standards, European standards, National standards.
Ozer, J. ( 1995). Video Compression for Multimedia London: Accademic Press.
Siegel, S. ( 1956). Nonparametric Statistics for the Behavioral Sciences. Tokyo: McGraw Hill Book Company.
Torgerson, W. S. ( 1958). Theory and Methods of Scaling. New York: John Wiley & Sons.