Residual processing circuit using single-path pipeline or multi-path pipeline and associated residual processing method

A residual processing method comprising:

• utilizing a single-path pipeline to process a current non-zero residual data block in a pipeline manner, wherein the single-path pipeline comprises an inverse scan (IS) circuit, an inverse quantization (IQ) circuit and an inverse transform (IT) circuit, and the current non-zero residual data block is at least a portion of a transform unit;
• and
• controlling pipelined processing of the current non-zero residual data block at the single-path pipeline, wherein the IS circuit is instructed to start IS processing of a next non-zero residual data block before the IT circuit finishes a first half of IT processing of the current non-zero residual data block.

A residual processing method comprising:

• utilizing a multi-path pipeline to process a plurality of non-zero residual data blocks, wherein the multi -path pipeline comprises a plurality of parallel single-path pipelines, each comprising an inverse scan (IS) circuit, an inverse quantization (IQ) circuit and an inverse transform (IT) circuit arranged to process a non-zero residual data block in a pipeline manner, the non-zero residual data block is at least a portion of a transform unit, and the parallel single-path pipelines comprise a first single-path pipeline and a second single-path pipeline;
• and
• controlling pipelined processing of the non-zero residual data blocks, wherein the second single-path pipeline is instructed to start pipelined processing of a next non-zero residual data block before the first single-path pipeline finishes a first half of IT processing of a current non-zero residual data block.