Multi-level significance map scanning

Abstract

Methods of encoding and decoding for video data are described in which multi-level significance maps are used in the encoding and decoding processes. The significant-coefficient flags that form the significance map are grouped into contiguous groups, and a significant-coefficient-group flag signifies for each group whether that group contains no non-zero significant-coefficient flags. A multi-level scan order may be used in which significant-coefficient flags are scanned group-by-group. The group scan order specifies the order in which the groups are processed, and the scan order specifies the order in which individual significant-coefficient flags within the group are processed. The bitstream may interleave the significant-coefficient-group flags and their corresponding significant-coefficient flags, if any.

Description

technical field

[0001] The present application relates generally to data compression, and in particular to methods and apparatus for encoding and decoding video using multi-level significance maps. Background technique

[0002] Data compression occurs in numerous contexts. Data compression is very commonly used in communications and computer networking to efficiently store, transmit and reproduce information. It finds specific application in the encoding of graphics, audio and video. Video presents considerable challenges to data compression due to the large amount of data required for each video frame and the speed at which encoding and decoding often needs to occur. The current state-of-the-art in video coding is the ITU-T H.264 / AVC video coding standard. The standard defines a number of different profiles for different applications, including a main profile, a baseline profile, and so on. A next-generation video coding standard currently under development through a jo...

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