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— This paper quantitatively evaluates the mutually compensatory property in audio–video transmission over the In-ternet by the psychometric method. In our previous study, we used MOS (Mean Opinion Score) as the user–level QoS parameter ; however, MOS is an ordinal scale, and therefore, its value does not necessarily represent exact difference between the(More)
×ØÖØ – This paper proposes a transport–layer error recovery scheme using retransmission for live audio–video streams transferred over QoS non-guaranteed networks. The scheme employs an enhanced version of the virtual–time rendering (VTR) media synchronization algorithm, which adjusts media rendering–time according to the network condition, and is referred(More)
— This paper proposes a scheme for quantitative assessment of user-level (or perceptual) QoS for audio-video transmission by means of two psychometric methods: the method of paired comparisons and the law of comparative judgment. Moreover, we discuss QoS mapping from application-level QoS to user-level QoS by principal component analysis and multiple(More)