Impact of Scan Conversion Methods on the Performance of Scalable Video Coding

Abstract

The ability to flexibly access coded video data at different resolutions or bit rates is referred to as scalability. We are concerned here with the class of methods referred to as pyramidal embedded coding in which specific subsets of the binary data can be used to decode lower-resolution versions of the video sequence. Two key techniques in such a pyramidal coder are the scan-conversion operations of down-conversion and up-conversion. Down-conversion is required to produce the smaller, lower-resolution versions of the image sequence. Up-conversion is used to perform conditional coding, whereby the coded lower-resolution image is interpolated to the same resolution as the next higher image and used to assist in the encoding of that level. The coding efficiency depends on the accuracy of this up-conversion process. In this paper techniques for down-conversion and up-conversion are addressed in the context of a two-level pyramidal representation. We first present the pyramidal technique ..