Slice Header Extension Length Signaling for Legacy HEVC Decoding

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Solution Overview

Problem

The existing High Efficiency Video Coding (HEVC) standard lacks support for extension fields in slice headers, making it difficult for both legacy and extension-compliant decoders to handle bitstreams with slice extensions, as legacy decoders cannot identify where the slice header ends and the slice data begins.

Innovation Solution

Introduce a length indicator in the slice header to indicate the length of the extension field, allowing legacy decoders to ignore the extension data while extension-compliant decoders can utilize it during decoding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If extension fields are added to slice headers, then adaptability and functionality are improved, but legacy decoder compatibility deteriorates

Engineering Contradiction:

Improveextension field supportVSAvoidlegacy decoder compatibility

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The slice header is segmented into a fixed part (understandable by legacy decoders) and an extension field (optional additional data). The extension field is separated and marked with a length indicator, allowing legacy decoders to ignore it while extension-compliant decoders can utilize it.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A length indicator syntax element is introduced as an intermediary between the fixed slice header and the extension field. This mediator tells legacy decoders how many bytes to skip over the extension data, enabling them to correctly identify the boundary between header and data without understanding the extension content.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If extension fields are added to slice headers, then functionality is improved, but device complexity increases

Engineering Contradiction:

Improveslice header extension capabilityVSAvoiddecoder complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Legacy decoders perform partial action by only processing the fixed slice header and ignoring the extension field. Extension-compliant decoders perform the full action by processing both the fixed header and the extension field. This allows the system to support extensions without forcing legacy decoders to become more complex.

Inventive Principle:

Principle #16Partial or excessive action

3Adaptability or versatility

If extension fields are added to slice headers, then adaptability is improved, but difficulty of detecting and measuring increases

Engineering Contradiction:

Improveextension field supportVSAvoidslice header boundary detection

Core Design Contradiction:

Adaptability or versatilityVSDifficulty of detecting and measuring

Solution Approach 1:

The length indicator is placed before the extension field to preliminarily indicate the extent of the extension data. This allows decoders to预先 know how many bytes to skip or process, making boundary detection straightforward without requiring complex analysis of the extension content.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS12501046B2Extension data handling

Publication Date: 2025.12.16 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

A length indicator associated with an encoded representation of a slice is parsed. The length indicator is indicative of a length of an extension field present in a slice header of the encoded representation. A decoder can then determine to ignore, during decoding of the encoded representation, any value of the extension field in the slice header where these values are identified based on the length indicator. As a consequence, an extension field can be added to slice headers and still enable legacy decoders to correctly decode the encoded representations.