Video Decoding Color Gamut Recognition Using SEI Metadata

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Solution Overview

Problem

Existing image encoding and decoding systems struggle to accurately recognize a color gamut of an encoding target image, as the color gamut is defined by an index identifying a fixed color gamut, making it difficult to handle variations beyond this fixed gamut.

Innovation Solution

The proposed solution involves the use of supplemental enhancement information (SEI) such as colour_primaries_info and ref_display_luminance_info to provide explicit color gamut and luminance information, allowing the decoding side to accurately recognize the color gamut of an encoding target image, even when it differs from the fixed standard.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If color gamut is defined by a fixed index in the standard, then the encoding system maintains compatibility with standard specifications, but the decoding side cannot accurately recognize color gamuts that differ from the fixed standard

Engineering Contradiction:
Improvecolor gamut recognition accuracyVSAvoidcolor gamut flexibility
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The encoding side performs preliminary action by determining the actual color gamut of the encoding target image before encoding, and embeds this information into the bitstream using SEI (Supplemental Enhancement Information) messages. This allows the decoding side to receive and utilize the pre-prepared color gamut data, enabling accurate recognition without relying solely on fixed standard indices.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

SEI (Supplemental Enhancement Information) acts as an intermediary mechanism between the encoding side and decoding side. It carries color gamut information that supplements the standard's fixed index system, allowing the transmission of precise color gamut data without disrupting the existing standard framework. This intermediary enables both standard compatibility and enhanced color gamut accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If supplemental enhancement information (SEI) is used to transmit color gamut information, then the decoding side can accurately recognize color gamut, but the amount of data to be transmitted increases

Engineering Contradiction:
Improvecolor gamut recognition accuracyVSAvoiddata transmission volume
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The system dynamically changes parameters based on the actual color gamut characteristics of the encoding target image. Instead of always transmitting full color gamut data, the encoding side adjusts the SEI message content according to whether the image uses standard or non-standard color gamuts, optimizing the data transmission volume while maintaining recognition accuracy.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3783900B1Decoding device and decoding method, encoding device, and encoding method
Publication Date: 2025.12.10 SONY GROUP CORP
  • EP3783900B1 patent drawingFigure 1
  • EP3783900B1 patent drawingFigure 2
  • EP3783900B1 patent drawingFigure 3

AI summary

The present disclosure relates to a decoding device, a decoding method, an encoding device, and an encoding method, which are capable of enabling a decoding side to accurately recognize a color gamut of an encoding target image. A receiving unit receives an encoded stream including encoded data of an image and color gamut information indicating a color gamut of the image from an encoding device that transmits the encoded stream. An extracting unit extracts the encoded data and the color gamut information from the encoded stream. A decoding unit decodes the encoded data, and generates the image. The present disclosure can be applied to, for example, a decoding device of a high efficiency video coding (HEVC) scheme.