The Quality-Oriented Adaptation Scheme (QOAS) supports the distribution of high quality multimedia services to a large number of simultaneous customers via given broadband IP infrastructure. This paper presents subjective testing results that augment previously reported objective performance assessment. Clips representing different classes of multimedia sequences in terms of motion content and types were selected and streamed using a QOAS-based prototype system. Congested delivery network conditions were emulated and the effects of the consequent QOAS-driven adaptations were subjectively assessed by end-users. The test subjects have also graded their perceived quality when using a nonadaptive streaming approach. The QOAS-related results were much higher than those obtained for a nonadaptive approach, being above the "good" perceptual level for all multimedia clips and in all tested delivery conditions.
- Adaptive multimedia streaming
- End-user perceived quality
- Feedback control
- Subjective testing