Encoder optimization of adaptive loop filters in HEVC

摘要

An optimized adaptive loop filter does not redesign filters inside the optimization loop of signaling depth which saves computations. Additionally, the Sum of Squared Errors (SSE) (distortion) of blocks is computed for the smallest blocks, thus, allowing for the distortion of larger blocks to be computed efficiently by adding block SSEs together which saves computations by removing redundant operations to calculate SSE of a block each time.

主权项

1. A method of implementing an optimized adaptive loop filter in a device comprising:
a. determining distortion with and without filtering for each block of an image; and b. determining if filtering of a current block reduces distortion in the block; c. if the filtering reduces the distortion, adding the filtered distortion to frame distortion; d. if the filtering does not reduce the distortion, excluding the current block from a training set and adding non-filtered distortion to the frame distortion; e. for each block at a current depth, combining distortions to find the distortion; f. determining total frame distortion and rate due to on/off switching and saving a new training data set; and g. redesigning filters based on the new training data set.