Patent ID: 11863765
Assignee: IMAGINATION TECHNOLOGIES LIMITED
Field: Audio-visual technology (Electrical engineering)
Classification: CPC H | IPC H

Claim 18:
19. The encoding unit of claim 16, wherein the block of pixels is a 4×4 block of pixels comprising four 2×2 quads of pixels;
wherein the Haar coefficient determining module is configured to:
determine, for each of the 2×2 quads of pixels, a set of Haar coefficients for the 2×2 quad of pixels, wherein the set of Haar coefficients comprises a plurality of differential coefficients and an average coefficient; and
output the average coefficients determined for each of the 2×2 quads of pixels, wherein the outputted average coefficients represent a 2×2 quad of coefficients;

wherein the coefficient encoding module is configured to determine, for each of the 2×2 quads of pixels, a first portion of the compressed data structure for the 2×2 quad of pixels using the differential coefficients determined for the 2×2 quad of pixels; and
wherein the encoding unit is configured to determine the second portion of the compressed data structure using the average coefficients determined for each of the 2×2 quads of pixels by:
using the Haar coefficient determining module to determine a set of L1 Haar coefficients for the 2×2 quad of coefficients, wherein the set of L1 Haar coefficients comprises a plurality of L1 differential coefficients and an L1 average coefficient;
using the coefficient encoding module to determine a first sub-portion of the second portion of the compressed data structure using the L1 differential coefficients determined for the 2×2 quad of coefficients, wherein the first sub-portion of the second portion comprises:
a first set of bits which indicates an order of the magnitudes of the L1 differential coefficients; and
a second set of bits which indicates a sign and an exponent for each of one or more of the L1 differential coefficients which are non-zero; and

determining a second sub-portion of the second portion of the compressed data structure using the L1 average coefficient determined for the 2×2 quad of coefficients.