language: en

RD-OPT: An Efficient Algorithm For Optimizing DCT Quantization Tables

Viresh Ratnakar
University of Wisconsin-Madison Computer Sciences Department
Madison, WI 53706

[Phone: (608) 262-6627]

Email: ratnakar@cs.wisc.edu
Miron Livny
University of Wisconsin-Madison Computer Sciences Department
Madison, WI 53706

[Phone: (608) 262-0856]

Email: miron@cs.wisc.edu

Abstract The Discrete Cosine Transform (DCT) is widely used in lossy image and video compression schemes such as JPEG and MPEG. In this paper we describe RD-OPT, an efficient algorithm for constructing DCT quantization tables with optimal rate-distortion tradeoffs for a given image. The algorithm uses DCT coefficient distribution statistics in a novel way and uses a dynamic programming strategy to produce optimal quantization tables over a wide range of rates and distortions. It can be used to compress images at any desired signal-to-noise ratio or compressed size.

1 Introduction