US Patent 11856227 Transform architecture in video encoding systems

Video encoding methods and apparatuses in a video encoding system receive an input residual signal of a current block by a shared transform circuit, apply horizontal transform and vertical transform by a shared transform circuit to generate transform coefficients, apply quantization and inverse quantization to generate recovered transform coefficients, apply inverse vertical transform and inverse horizontal transform to the recovered transform coefficients by the shared transform circuit to generate a reconstructed residual signal for the current block, and encode the current block based on quantized levels of the current block. The shared transform circuit and a coefficient buffer in the folded 4-time transform architecture reuse computation resources in each transform stage. In some embodiments of the folded 4-time transform architecture, a hierarchical design for block size grouping is implemented with fixed throughput for uniform hardware scheduling.