Control of perceived quality of service in multimedia retrieval services: prediction-based mechanism vs. compensation buffers

Abstract

In multimedia systems end-to-end delay jitter has a great impact on the continuity of information playback. Therefore, it is necessary to introduce appropriate mechanisms to compensate for delay variations, so that the intramedia and intermedia temporal relationships can be preserved. In this paper, two methods for compensation of the network delay jitter in a distributed multimedia retrieval service are compared: the first is based on prediction of the network delay jitter suffered by each information unit and retrieval time modification at the source site; the second is based on a compensation buffer at the destination site. Comparison is made by assuming a master/slave relationship between the monomedia streams composing the multimedia data flow.

Assessed quality of service and voice and data integration: A case study

“…This layer was introduced taking into account the requirements of multimedia services and essentially refers to media synchronization. At present, a multimedia stream is characterized by multiple monomedia streams related to each other by means of time, spatial or logical relationships that can be altered when the information unit crosses a network and that must be preserved [15]. At this level, the QoS parameters are basically linked to the skew occurring in the multimedia stream, that is the difference between the instantaneous delays of information units belonging to two different monomedia streams composing the multimedia stream, in other words skew refers to the timing difference which occurs when information units which are traveling over different pathes reach their destinations at different times.…”

“…The QoS parameters can be expressed in terms of variation of delay average value during the passage from one cell to another and in terms of the number of information units that are lost or duplicated during the handover. Also in this case, the QoS parameters can be expressed as restrictions of the statistics values [15].…”

Adaptive Synchronization of Semantically Compressed Instructional Videos for Collaborative Distance Learning

“…Theoretically, the baseline client should receive a score of 1. Note that we formulated this scoring system because other scoring systems (e.g., [Baqai et al, 1996;Corte, Lombardo, Palazzo, & Schembra, 1998;Wang, Ostermann, & Zhang, 2002) measure unrelated factors such as the synchronization between different streams (audio and video), image resolution, or human perceived quality, and are not constrained by the group synchronization requirement. This restriction mandates a scoring system sensitive to the relative differences between quality hierarchies.…”

Mobility and quality of service across heterogeneous wireless networks

“…This layer was introduced taking into account the requirements of multimedia serv-ices and basically refers to media synchronization. A multimedia stream is, actually, characterized by multiple monomedia streams related to each other by means of time, spatial or logical relationships that can be altered when the information unit crosses a network and that must be preserved [33]. At this level, the QoS parameters are basically linked to the skew occurring in the multimedia stream, that is the difference between the instantaneous delays of information units belonging to two different monomedia streams that compose the multimedia stream.…”

“…The QoS parameters can be expressed in terms of the variation of average delay during the passage from one cell to another and in terms of the number of information units that are lost or duplicated during the handover. Also in this case, the QoS parameters can be expressed as restrictions on the statistic values [33].…”