VVC Sublayer_Level_idc Parsing With a Single Reverse Scan

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Solution Overview

Problem

In the current version of VVC, decoding the sublayer_level_idc[i] array requires two scans of the bitstream, one in increasing order and one in decreasing order, leading to increased decoding complexity.

Innovation Solution

Modify the parsing/decoding of sublayer_level_idc[i] to be done in decreasing order of index i, allowing the values of the sublayer_level_idc[i] array to be set in a single scan, thereby reducing decoding complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If two scans of the bitstream are performed (one in increasing order and one in decreasing order), then the sublayer_level_idc[i] array values can be determined according to the VVC specification, but the decoding complexity increases

Engineering Contradiction:

Improvecorrectness of sublayer_level_idc[i] array determinationVSAvoiddecoding complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent inverts the conventional two-scan approach by performing a single scan in decreasing order of index i (from maxNumSubLayersMinus1 down to 0). This reversal of the scanning direction allows the decoder to determine all sublayer_level_idc[i] values in one pass, eliminating the need for the second increasing-order scan and thereby reducing decoding complexity while maintaining correctness

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent extracts and eliminates the redundant second scan operation from the decoding process. By recognizing that the decreasing-order scan alone suffices to determine all necessary sublayer_level_idc[i] values, the method removes the unnecessary increasing-order scan, reducing the computational workload and simplifying the decoding procedure

Inventive Principle:

Principle #2Taking out (Extraction)

Data Source

PatentUS20250294158A1Derivation of a value for each layer representation of a bitstream

Publication Date: 2025.09.18 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

There is provided a method for processing a bitstream. The method comprises determining a value, N, wherein N identifies a number of ordered layer representations, wherein N is greater than or equal to 3 such that the N ordered layer representations comprises a highest layer representation, a second highest layer representation, and a third highest layer representation. The method further comprises determining a value for the highest layer representation. The method comprises, after determining the value for the highest layer representation and before determining a value for the third highest layer representation, determining a value for the second highest layer representation. The method comprises, after determining the value for the second highest layer representation, determining a value for the third highest layer representation.