Decoder-Side Intra Mode Derivation with Texture Analysis in VVC Test Model

The standardization of the next generation video codec, called Versatile Video Coding (VVC), has been progressing fast since 2018. At the same video quality, the VVC Test Model (VTM) currently provides about 27% bitrate saving compared to the preceding High Efficiency Video Coding (HEVC) standard. The ultimate objective is to reach about 50% improvement by the end of 2020. This paper presents an intra coding algorithm for VTM that skips the mode signaling at the encoder side and leaves it to be derived at the decoder side. To this end, a Histogram of Gradient (HoG) is computed from the texture of the previously reconstructed pixels and processed to derive the intra mode. Moreover, the proposed method is tuned to minimize its side-effects on the existing intra coding tools. Experimental results, on top of VTM-3.0, show that the proposed algorithm brings -0.22% BD-rate gain, with a negligible complexity.