Merge-Block MTSS Inheritance for Faster Video Transform Coding

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Solution Overview

Problem

Existing video coding systems face challenges in efficiently managing multiple transform set selection (MTSS) during encoding and decoding processes, particularly in block-based and wavelet-based systems, which can impact compression efficiency and quality.

Innovation Solution

Implementing a device or method that enables the inheritance of MTSS information by determining if a merge mode is enabled for a current block, copying relevant transform set selection indices and flags, and adjusting based on virtual intra prediction mode values to facilitate efficient encoding and decoding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple transform set selection (MTSS) is implemented during encoding and decoding, then compression efficiency and quality are improved, but device complexity and processing overhead increase

Engineering Contradiction:
Improvecompression efficiencyVSAvoidprocessing overhead
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by determining merge mode status before performing MTSS operations. The encoder/decoder checks whether merge mode is enabled for the current block prior to copying transform set selection indices, allowing the system to prepare and conditionally execute MTSS operations only when beneficial, thus improving compression efficiency while controlling processing overhead through selective application

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements local quality by selectively copying MTSS information only for blocks where merge mode is enabled and virtual intra prediction mode values meet specific criteria. Rather than applying MTSS universally, the system locally adapts transform set selection to individual block characteristics, optimizing compression efficiency for relevant blocks while avoiding unnecessary processing overhead for others

Inventive Principle:
Principle #3Local quality

2Speed

If transform set selection indices are copied from merge blocks, then encoding and decoding speed is improved, but accuracy of transform selection may be reduced

Engineering Contradiction:
Improveencoding and decoding speedVSAvoidtransform selection accuracy
Core Design Contradiction:
SpeedVSMeasurement precision

Solution Approach 1:

The patent applies feedback by using virtual intra prediction mode values to control the copying of MTSS information. The encoder/decoder calculates VIPM values and compares them against thresholds to determine whether to inherit transform set selection indices from merge blocks. This feedback mechanism ensures that speed optimizations through copying are applied only when the current block's characteristics justify using the merge block's transform selection, thereby maintaining transform selection accuracy while improving overall processing speed

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent implements parameter changes by using virtual intra prediction mode values as conditional parameters that control MTSS information copying. When VIPM values fall within specific ranges or meet certain thresholds, the system changes the behavior from calculating original transform selections to copying pre-determined indices from merge blocks. This parameter-based control allows the system to achieve speed improvements through copying while maintaining accuracy by only applying copying when block characteristics support it

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4687340A1Inheriting multiple transform set selection information
Publication Date: 2026.02.04 INTERDIGITAL CE PATENT HOLDINGS SAS
  • EP4687340A1 patent drawingFigure 1A
  • EP4687340A1 patent drawingFigure 1B
  • EP4687340A1 patent drawingFigure 1C

AI summary

Systems, methods, and instrumentalities disclosed herein for a video encoding and/or decoding device including a processor. The device may be configured to determine that a merge mode is enabled for a current block. Based on the determination, the device may copy, from a merge block, a multiple transform selection (MTS) multiple transform set selection (MTSS) index that indicates a transform set from a plurality of transform sets. The device may encode and/or decode the current block based on at least the MTS MTSS index. Based on the determination, the device may copy at least one of an MTS flag, an MTS index, a low-frequency non-separable transform (LFNST) MTSS index, an LFNST flag, or an LFNST index.