Video coding method using at least evaluated visual quality and related video coding apparatus

A video coding apparatus, comprising:

• a visual quality evaluation circuit, arranged to evaluate visual quality based on data involved in a coding loop;
• a rate controller, arranged to calculate pixel-based distortion by estimating pixel variance of a rate-controlled unit in a source frame, and refer to at least the evaluated visual quality and the pixel-based distortion for deciding a target bit allocation of the rate-controlled unit, wherein the rate controller performs a coarse decision according to one of the evaluated visual quality and the pixel-based distortion to determine a plurality of coarse bit allocations, and performs a fine decision according to another of the evaluated visual quality and the pixel-based distortion to determine at least one fine bit allocation from the coarse bit allocations, where the target bit allocation is derived from the at least one fine bit allocation;
• and
• a coding circuit, comprising the coding loop, the coding circuit arranged to encode the rate-controlled unit according to the target bit allocation.

A video coding method, comprising:

• calculating pixel-based distortion by estimating pixel variance of a rate-controlled unit in a source frame;
• utilizing a visual quality evaluation circuit for evaluating visual quality based on data involved in a coding loop;
• and
• referring to at least the evaluated visual quality and the pixel-based distortion for deciding a target bit allocation of the rate-controlled unit in video coding, comprising:
• referring to the evaluated visual quality to find a first bit allocation;
• referring to the pixel-based distortion to find a second bit allocation;
• and
• selecting one of the first bit allocation and the second bit allocation as the target bit allocation.

A video coding apparatus, comprising:

• a visual quality evaluation circuit, arranged to evaluate visual quality based on data involved in a coding loop;
• a rate controller, arranged to calculate pixel-based distortion by estimating pixel variance of a rate-controlled unit in a source frame, and refer to at least the evaluated visual quality and the pixel-based distortion for deciding a target bit allocation of the rate-controlled unit, wherein the rate controller refers to the evaluated visual quality to find a first bit allocation, refers to the pixel-based distortion to find a second bit allocation, and selects one of the first bit allocation and the second bit allocation as the target bit allocation;
• and
• a coding circuit, comprising the coding loop, the coding circuit arranged to encode the rate-controlled unit according to the target bit allocation.