Methods and systems for pipelining within binary arithmetic coding and decoding

摘要

Methods of encoding and decoding for video data are described for encoding or decoding multi-level significance maps while enabling pipelining of the BAC engine. In one example, coefficient groups are redefined to remove the significant-coefficient flags of the first and last position of a block and replace them with significant-coefficient flags of the last position in the previous block and the first position in the next block. A modified scan order is applied to each coefficient group. In another example, the coefficient groups remain block-based, but the scan order is modified to interleave the encoding and decoding sequential coefficient groups.

主权项

1. A method of decoding a bitstream of encoded video by reconstructing significant-coefficient flags for a transform unit, the transform unit comprising a sequence of blocks, the bitstream including sets of significant-coefficient flags, each set corresponding to a respective block, the method comprising:
for each set of significant-coefficient flags, decoding that set in a scan order, wherein the scan order is a diagonal scan within its respective block modified so as to
decode a significant-coefficient flag in the bottom-right-corner position within the respective block corresponding to the set, prior to decoding at least two significant-coefficient flags of a previous set in the sequence, anddecode a significant-coefficient flag in the upper-left-corner position within that respective block, after decoding at least two significant-coefficient flags of a subsequent set in the sequence.