Low bit-rate intra coding scheme based on constrained quantization and median-type filter

This paper presents a new intra coding scheme for low bit-rate video compression. We first propose an improved codec architecture based on HEVC encoder. Then we divide pixels in each prediction block into two parts: three quarters of pixels are coded via a smart padding technique together with a constrained quantization algorithm (leading to a significantly improved quality); whereas the other quarter are reconstructed according to median-type filtering by utilizing the 8-neighboring reference samples after all blocks have been encoded and reconstructed. Experimental results show that about 3% BD-rate reduction has been achieved both for luma and chroma components without apparent increase of encoding complexity with respect to the original HEVC intra coding.