Parallel pyramid entropy coding for video and image compression

摘要

Methods, systems, and computer program products are provided to divide code blocks, such as blocks of quantized coefficient of image or video data, into smaller blocks and sub-blocks that can be processed in parallel using layered entropy coding and decoding scheme. This division is accomplished while still encoding the entire code block using the same layered entropy coding scheme.

主权项

1. A method, comprising:
dividing a code block into a plurality of pixel groups; for a pixel group from the plurality of pixel groups, analyzing a first cluster pattern from a plurality of cluster patterns in a layered encoding scheme for the code block, wherein the first cluster pattern arranges the pixel group into sub-blocks, and wherein the analyzing comprises:
calculating maximum code sizes for encoding the sub-blocks according to the layered encoding scheme,determining a largest code size of the maximum code sizes, andcalculating a prefix size of a prefix that encodes the maximum code sizes, wherein the maximum code sizes are encoded as differences from the largest code size; determining that the first cluster pattern is associated with a first pixel group code size that is smaller than a second pixel group code size associated with a second cluster pattern from the plurality of cluster patterns, wherein the first pixel group code size is calculated based on the maximum code sizes and the prefix size; selecting the first cluster pattern based on the determination; dividing the pixel group into the sub-blocks according to the first cluster pattern; and encoding the prefix and pixels assigned to the sub-blocks using the layered encoding scheme.