Variable block-size transform and entropy coding at the enhancement layer of FGS

This paper proposes the variable block-size transform and
context-based entropy coding techniques for the enhancement
layer of FGS (Fine Granularity Scalable) video coding.
First, the variable block-size transform is introduced
into the enhancement layer to improve the performance of
FGS in terms of both visual quality and PSNR. Different
from that used in the traditional single layer coding, an RD
selection algorithm is proposed to optimally decide the
transform size of each block under consideration of the
consistent performance at a range of bit rate. Furthermore,
to fully take the advantage of the characteristics and correlations
of symbols coded in the FGS enhancement layer,
different context models are designed for the arithmetic
coding according to symbol type and transform size. Experimental
results show that the coding efficiency of FGS
can be increased 0.2-0.9dB with the proposed techniques.