Until recently, Quality of Service (QoS) in conventional broadcast and multimedia systems had focused solely on mono-modal sensations. Most related quality metrics are based on simplified models of parts of the human sensory system and subsequent feature extraction to capture the characteristics of the stimuli that are most relevant from a perceptual point of view. Those features can then be combined to form a Quality of Experience (QoE) rating. The main challenges in this final combination step are to assign perceptually meaningful weights to the features and to correctly model interdependencies and masking effects between features. Whereas QoS intends to capture the system-related characteristics, QoE involves aspects related to subjective perception, user behavior and needs, appropriateness, context, and usability of the delivered content.

Qualinet therefore focuses on a fundamental issue, which if successfully accomplished, will have a tremendous benefit for multimedia system users.