Logical Mapping: An Intermedia Synchronization Model for Multimedia Distributed Systems

Abstract

Abstract-The preservation of temporal dependencies among different media data, such as text, still images, video and audio, and which have simultaneous distributed sources as origin, is an open research area and an important issue for emerging distributed multimedia systems, such as Teleimmersion, Telemedicine, and IPTV. Although there are several works oriented to satisfy temporal dependencies in distributed multimedia systems, they are far from resolving the problem. In this paper we propose a logical synchronization model able to specify at runtime any kind of temporal relationship among the distributed multimedia data involved in a temporal scenario. The synchronization model is based on a new concept that we call logical mapping. A logical mapping, in general terms, translates a temporal relation based on a timeline to be expressed according to its causal dependencies. The logical mappings allow us to avoid the use of global references, such as a wall clock and shared memory. We note that the proposed intermedia synchronization model does not require previous knowledge of when, nor of how long, the media involved of a temporal scenario is executed. Finally, in order to show the viability of the proposed model, a syncrhonization approach is presented.

An Asymmetric Mechanism to Synchronize Continuous Media in Mobile Distributed Systems

“…Numerous works have proposed mechanisms to carry out the synchronization at runtime [1][2][3][4][5][6]. Nevertheless, these works cannot be applied for mobile distributed systems due to the fact that they do not consider the inherent characteristics of a mobile distributed system, such as: limited processing and storage capabilities in mobile hosts, and limited bandwidth on wireless communication channels.…”

Temporal Alignment Model for Data Streams in Wireless Sensor Networks Based on Causal Dependencies

“…The works of Shimamura et al [15] and Pomares et al [11] define the following ordered interval composition.…”

“…According to Definition 4 and Pomares et al [11], the happened-before relation in regard to ordered intervals can be expressed only in terms of the endpoints as follows. Property 1.…”

“…Let and be two ordered intervals. and are said to be simultaneous (denoted by ||| ) if the following condition is satisfied [11]:…”

“…The logical mapping model introduced in [11] is useful to represent pairwise interactions between processes. Such model expresses temporal relations between sets of events in terms of the happenedbefore relation for intervals.…”