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Summary: AN ANALYSIS OF THE DCT COEFFICIENT DISTRIBUTION WITH THE H.264 VIDEO
CODER
Yucel Altunbasak and Nejat Kamaci
Center for Signal and Image Processing
Georgia Institute of Technology
Atlanta, GA 30332
email:{yucel,kamaci}@ece.gatech.edu
ABSTRACT
By extensive analysis with several video sequences, we observed
that the statistical distribution of the DCT coefficients in typical
video coding applications is closer to a Cauchy distribution than to
a Laplacian distribution. We developed the rate and the distortion
expressions as a function of the video coder quantization param-
eter based on this observation. Experiments with an H.264 codec
demonstrate that the Cauchy distribution based expressions pro-
vide better estimates for the actual rate and distortion than those
that are based on the Laplacian distribution.
1. INTRODUCTION
Most image and video coding standards use a block based two-
dimensional discrete cosine transform (DCT) or an approxima-
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