Circular-shift transformation for image and video coding

Abstract

Image coding using circular-shift transformation includes generating a reconstructed image by obtaining a circular-shift indicator indicating that circular-shift transformation is enabled for a current block by decoding the circular-shift indicator from an encoded bitstream, obtaining quantized transform coefficients for the current block by entropy decoding the quantized transform coefficients from the encoded bitstream, obtaining circular-shift offsets for the current block by decoding the circular-shift offsets from the encoded bitstream, obtaining dequantized transform coefficients for the current block by dequantizing the quantized transform coefficients, obtaining reconstruction circular-shifted residual values for the current block by inverse transforming the dequantized transform coefficients, obtaining reconstruction residual values for the current block by inverse circular shifting the reconstruction circular-shifted residual values, generating prediction values for the current block, obtaining reconstructed pixels for the current block by combining the reconstruction residual values and the prediction values, and including the reconstructed pixel in the reconstructed image.