Scan-Based LSC Indicator Conversion for Video Decoding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional video encoders face challenges in determining the significance of transform coefficients in a block-based video coding system, particularly when using a reverse scanning order, which hinders the video decoder's ability to accurately decode significance maps and level information.
Innovation Solution
The proposed solution involves converting a block-based last significant coefficient (LSC) indicator into a scan-based LSC indicator, allowing the video decoder to determine the ordinal position of the last significant coefficient according to the scanning order, thereby enabling accurate decoding of significance maps and level information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a block-based LSC indicator is used to indicate coordinates of the last significant coefficient, then the decoding process can be simplified, but the decoder cannot accurately determine the ordinal position of the LSC according to scanning order
Solution Approach 1:
The patent introduces an intermediary conversion process that transforms the block-based LSC indicator (coordinate system) into a scan-based LSC indicator (ordinal position system). This intermediary step acts as a bridge between the simplified block-based representation and the scanning-order-based decoding process, allowing the decoder to accurately determine the ordinal position of the LSC without directly processing complex coordinate transformations.
2Loss of information
If coordinates of the LSC are signaled directly, then less information needs to be transmitted, but the significance map cannot be accurately decoded
Solution Approach 1:
The conversion from block-based LSC indicator to scan-based LSC indicator serves as an intermediary process that preserves the compact representation benefits while enabling accurate significance map decoding. The intermediary conversion ensures that the transmitted coordinate information is properly transformed into ordinal position information that the decoder can use reliably.
3Productivity
If the decoder processes transform coefficients without converting block-based indicator to scan-based indicator, then processing speed is faster, but decoding accuracy is reduced
Solution Approach 1:
The patent applies preliminary action by performing the LSC indicator conversion before the actual significance map decoding process. This preliminary conversion prepares the LSC position information in the correct format (scan-based indicator), ensuring that subsequent decoding operations can proceed accurately without requiring complex runtime calculations or iterations.
Data Source
AI summary
A video decoder converts a block-based LSC indicator into a scan-based LSC indicator. The block-based LSC indicator indicates coordinates of a last significant coefficient of a block of transform coefficients according to a scanning order. The scan-based LSC indicator indicates an ordinal position of the LSC according to the scanning order. The video decoder may decode, based on the scan-based LSC indicator, a significance map for the block.