Spatial transform skip in the emerging High Efficiency Video Coding standard

Abstract

To meet the still growing compression efficiency needs for high definition content, ITU and MPEG are now defining the High Efficiency Video Coding (HEVC) standard. The HEVC codec still relies on a hybrid motion compensated predictive video coding architecture as its H.264/AVC ancestor though novel coding tools are introduced. These novel coding tools provide a highly uncorrelated prediction residue for which classical frequency decomposition methods as the discrete cosine transform may not provide an effective energy compaction. Therefore this paper proposes a transform skip mode which allows skipping one or both directions where the transform is applied. The proposed transform skip mode is integrated in the HEVC codec and is able to provide bitrate reductions of up to 5% at the same objective quality when compared with the HEVC reference codec.

Implicit Seleted Transform Skip Method For Avs3

“…Transform skip method can effectively improve the SCC performance since the frequency decomposition method as DCT cannot provide effective energy compaction. In [7], the transform skip method is proposed for inter-coded blocks, and it can be performed to skip the horizontal or vertical transform separately. The transform skip types are signaled explicitly.…”

Mirroring of coefficients for Transform Skipping in Video Coding

“…That includes new transforms, larger block structures, advanced intra and inter predictions and improved coefficient coding. It has also been suggested in related research, that while discrete cosine transform (DCT) and discrete sine transform (DST) tools in HEVC usually have significant contributions to the coding efficiency, skipping the transform altogether for selected blocks could also help in some circumstances [2]. These improvements through transform skip are particularly noted in coding Screen Content due to their unique spatial and temporal characteristics [3].…”