An embedded codec (EBC) circuitry includes a memory to store a plurality of one dimensional (1D) sub-blocks of quantized-transformed residual levels for a 1D image block and encoder circuitry to determine a sub-block category from a set of sub-block categories for each 1D sub-block of the plurality of 1D sub-blocks. The encoder circuitry encodes the plurality of 1D sub-blocks by application of an entropy coding scheme to generate a plurality of encoded 1D sub-blocks. The encoder circuitry allocates a plurality of refinement bits at bit-positions in bit-planes corresponding to encoded quantized-transformed residual levels in an encoded 1D sub-block of the plurality of encoded 1D sub-blocks, based on the determined sub-block category of a corresponding 1D sub-block.