Browsing by Author "Foresti, Mark"

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    Human Perception of Media and Synchronization Losses
    (1997) Wijesekera, Duminda; Srivastava, Jaideep; Foresti, Mark
    Perception of multimedia quality, specified by quality of service (QoS) metrics can be used by system designers to optimize customer satisfaction within resource bounds enforced by general purpose computing platforms. Media losses, rate variations and transient synchronization losses have been speculated to affect human perception of multimedia quality. This paper presents metrics to measure such defects, and results of a series of user experiments that justify such speculations. Results of the study provide bounds on losses, rate variations and transient synchronization losses as a function of user satisfaction, in the form of Likert values. It is shown how these results can be used by algorithm designers of underlying multimedia systems.
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    Performance Evaluation of Synchronization Losses in the Continuous Media Toolkit
    (1997) Wijesekera, Duminda; Parikh, Shwetal; Varadarajan, Srivatsan; Srivastava, Jaideep; Nerode, Anil; Foresti, Mark
    This paper presents a performance analysis of synchronization services provided by the Berkeley Continuous Media Toolkit (CMT). The quality of audio-video synchronization is measured against processor and network loads for both remote and local clients. The metrics of analysis are the perceptible and tolerable human perceptual limits reported by Steinmetz, and another metric designed to measure synchronization of lossy media streams. It is shown that according to Steinmetz' metric CMT provides imperceptible audio-video mis-synchronization for about 10 seconds, and tolerable synchronization for about 13 seconds from the start of the clips for local clients under low processor loads. It is also shown that under high loads, synchronization is achieved at the cost of losing media frames.