Last Coefficient Position Coding for Faster Image Decoding
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Solution Overview
Problem
Current video coding standards face inefficiencies in arithmetic coding and decoding of last position information, particularly due to frequent switching between different arithmetic decoding methods, which hinders efficient processing.
Innovation Solution
An image coding method that binarizes and codes the last position information by separating it into components, using context adaptive binary arithmetic coding and bypass coding, and arranging the coded signals in a bit stream to minimize switching between decoding methods, allowing for efficient decoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional arithmetic coding methods are used for last position information, then coding completeness is maintained, but decoding efficiency deteriorates due to frequent switching between different arithmetic decoding methods
Solution Approach 1:
The last position information is segmented into two separate components: a first component indicating the last non-zero coefficient position in scan order, and a second component indicating the run length of zero coefficients following it. Each component is independently coded using the same arithmetic coding method, eliminating the need to switch between different decoding methods and thereby improving decoding efficiency while maintaining complete coding capability.
2Speed
If multiple arithmetic decoding methods are used for different parts of last position information, then coding precision is maintained, but processing speed deteriorates due to method switching overhead
Solution Approach 1:
The last position information is divided into two components that are each coded with the same arithmetic coding method, eliminating method switching overhead and improving processing speed.
Solution Approach 2:
The invention changes the parameter representation by using a unified arithmetic coding approach for both components, where the first component represents the last non-zero coefficient position and the second component represents the run length of zeros. This parameter transformation allows single-method coding while preserving complete information precision.
3Loss of information
If conventional binarization methods are used for last position information, then information completeness is maintained, but computational overhead increases due to frequent decoding method switching
Solution Approach 1:
The last position information is segmented into two binarized components: the first component binarizes the last non-zero coefficient position in scan order, and the second component binarizes the run length of zero coefficients. Both components are decoded using the same arithmetic decoding method, which maintains complete information while reducing computational overhead by eliminating method switching.
Data Source
AI summary
An apparatus is provided for decoding last position information indicating a horizontal position and a vertical position of a last non-zero coefficient in a predetermined order within a current block to be decoded, the current block being included in a picture and including a plurality of coefficients. The apparatus includes one or more processors, a communication unit, and storage coupled to the one or more processors and the communication unit. The communication unit is configured to transmit a request for a bitstream to an external system, and receive the bitstream from the external system. The one or more processors are configured to obtain the bitstream, perform first arithmetic decoding, perform second arithmetic decoding, derive a horizontal component of the last position information, and derive a vertical component of the last position. A system for decoding and a displaying method are also provided.