Encoding and transcoding multiple video objects with variable temporal resolution

A key advantage of object-based coding schemes is that the quality of each video object may be varied. In this paper we describe the problem associated with varying the temporal quality of multiple video objects, also referred to as the composition problem. We propose a solution to this problem that is based on changes in the shape boundaries over time. Finally, we discuss how this shape feature, or shape hint, can be used to vary the temporal resolution of multiple video objects. The use of the proposed shape hint may be considered within an encoding or transcoding application. This hint has also been adopted into the emerging MPEG-7 standard.