Adaptation of multimedia resources supported by metadata
The Video adaptation is an active research area aiming at delivering heterogeneous content to yet heterogeneous devices under different network conditions. This paper presents a novel method of video adaptation called segment-based variation. It aims at applying different reduction methods on different segments based on physical content. The video is first partitioned into homogeneous segments based on the physical characteristics of motion, texture, and color. Then optimal reduction methods are selected and applied on each segment with the objective of minimizing quality loss and/or maximizing data size reduction during adaptation. In addition, the commonly used reduction methods are also implemented. To realize variation creation utilizing these methods, a unifying framework called the Variation Factory is developed. It is extended to the Multi-Step Variation Factory, which allows intermediary videos to serve as variations and also as sources to further variations. It creates a tree of variations and the associated metadata, which allow one to apply successive reductions by active network nodes. They also allow the server to easily switch from one stream to another depending on resource availability. Our proposals are implemented as part of a server component, called the Variation Processing Unit (VaPU) offering user interface to guide the generation of the different versions of the source and an MPEG-7 metadata document. The information contained in this document describes both the source and the variations and helps the system to identify the most appropriate version. It can also be used by active components on the network to carryout efficient adaptation. Such adaptation will take user preferences, including disability, into account.
metadata video adaptation segment-based variation mpeg-7 uma content accessibility