Spatial Motion Vector Scaling Using Temporal Predictor

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Solution Overview

Problem

Scalable video coding techniques face increased processing costs due to the need for division operations in spatial motion vector scaling and inter-layer position mapping, especially when dealing with layers of different spatial scalability in High Efficiency Video Coding (HEVC) and its extensions.

Innovation Solution

The implementation of a method that uses a temporal scaling function, such as the Temporal Motion Vector Predictor (TMVP) scaling function, to perform spatial motion vector scaling without division operations, and introduces scaling parameters for horizontal and vertical directions to optimize scalability ratios, reducing computational and memory requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If spatial motion vector scaling is performed using conventional methods, then motion vector accuracy is improved, but processing complexity increases due to division operations

Engineering Contradiction:
Improvemotion vector accuracyVSAvoidprocessing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the parameter representation by using scaled integer arithmetic instead of floating-point division. Motion vectors are represented with scale factors (e.g., 1/16, 1/32, 1/64) and integer operations are used to perform scaling through bit shifting and multiplication, avoiding division operations while maintaining precision.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical division operation with an equivalent computational mechanism using multiplication and bit shifting. The division-free approach substitutes the traditional division-based scaling mechanism with a more efficient arithmetic mechanism that achieves the same scaling effect without the computational overhead of division.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If division operations are used for spatial scaling, then scaling precision is improved, but computational cost increases

Engineering Contradiction:
Improvescaling precisionVSAvoidcomputational cost
Core Design Contradiction:
Measurement precisionVSPower

Solution Approach 1:

The patent transforms the scaling operation from division-based to multiplication-based with bit shifting. By representing scale factors as powers of two (1/16, 1/32, 1/64), the patent enables precise scaling through efficient bit manipulation operations that maintain precision while reducing computational power requirements.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent substitutes the computationally expensive division mechanism with a more efficient multiplication and bit-shifting mechanism. This replacement maintains scaling precision while significantly reducing the computational power needed to perform the operation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If arbitrary division operations are performed for inter-layer position mapping, then mapping accuracy is improved, but processing time increases

Engineering Contradiction:
Improvemapping accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent changes the arithmetic parameters by using integer-based scaling with predetermined scale factors instead of arbitrary division. This allows position mapping to be performed using efficient integer arithmetic operations that maintain mapping accuracy while reducing processing time through avoidance of division operations.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent performs preliminary preparation by establishing predetermined scale factors and integer representations before the actual mapping operation. This preliminary action enables the mapping to be executed using pre-computed parameters and efficient integer arithmetic, reducing the time required during actual processing while maintaining accuracy.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2962463B1Spatial motion vector scaling for scalable video coding
Publication Date: 2019.10.30 QUALCOMM INC
  • EP2962463B1 patent drawingFigure 1
  • EP2962463B1 patent drawingFigure 2
  • EP2962463B1 patent drawingFigure 3

AI summary

In one implementation, an apparatus is provided for encoding or decoding video information. The apparatus comprises a memory unit configured to store video information associated with a base layer and/or an enhancement layer. The apparatus further comprises a processor operationally coupled to the memory unit. In one embodiment, the processor is configured to determine a scaling factor based on spatial dimension values associated with the base and enhancement layers such that the scaling factor is constrained within a predetermined range. The processor is also configured to spatially scale an element associated with the base layer or enhancement layer using the scaling factor and a temporal motion vector scaling process.