Video Decoder Scan Order Adaptation for Transform Subarea Signaling
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Solution Overview
Problem
Current video coding technologies face inefficiencies in selecting transform types for blocks of pictures, leading to increased signaling overhead and complexity, particularly when non-DCT-II transforms are used, as they require non-zero coefficients to be within a predetermined subarea, causing unnecessary signaling of the DCT-II transform.
Innovation Solution
Implementing a decoder/encoder that uses different coefficient scan orders based on the transform type, allowing for efficient decoding/encoding by checking if non-zero coefficients are within or outside a predetermined subarea, thereby reducing unnecessary signaling and improving coding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If non-DCT-II transforms are used with a predetermined subarea constraint, then transform coding flexibility is improved, but signaling overhead increases due to unnecessary DCT-II transform signaling
Solution Approach 1:
The patent extracts and removes the unnecessary DCT-II transform signaling from the bitstream. By implementing a mechanism that detects when non-DCT-II transforms are used and automatically suppressing the DCT-II syntax element signaling, the invention eliminates redundant information transmission while maintaining transform coding flexibility.
Solution Approach 2:
The decoding system uses self-service by automatically detecting the transform type from the transform coefficient data characteristics and autonomously determining whether DCT-II signaling should be suppressed. The system serves itself by making intelligent decisions about syntax element transmission based on the actual transform being applied, without requiring explicit external control signals.
2Productivity
If multiple transform types are enabled for different block sizes, then coding efficiency is improved, but device complexity increases due to multiple transform implementations
Solution Approach 1:
The patent implements a universal transform processing framework that can handle multiple transform types (DCT-II, DST-VI, and other integer transforms) through a unified architecture. The system uses a single transform processing unit that adaptively selects and executes the appropriate transform based on block size and content characteristics, eliminating the need for separate dedicated transform implementations for each transform type.
Solution Approach 2:
The invention changes the operational parameters of the transform processing system dynamically based on the input block characteristics. By adjusting transform parameters such as block size, transform type selection, and processing mode based on the actual video content and block properties, the system achieves high coding efficiency without requiring complex fixed implementations for all possible transform scenarios.
3Ease of operation
If transform coefficient levels are coded before transform type selection, then decoding complexity is reduced, but coding flexibility is limited
Solution Approach 1:
The patent applies preliminary action by performing transform coefficient level coding in advance, before the transform type is fully determined. The system prepares and encodes the coefficient levels using a default or predicted transform type, then later refines or adjusts the coding based on the actual selected transform type. This allows the decoding process to start with pre-prepared data while still achieving optimal transform-specific compression.
Data Source
AI summary
Decoder for decoding a transformed representation of a sample block from a data stream. If a first coded coefficient is located inside a predetermined subarea of the transform coefficient block and if the underlying transform is within a first set of available transforms, the decoder decodes coefficients along a first coefficient scan order. If the transform is within a second set of available transforms, the decoder decodes coefficients located within the predetermined subarea along a second coefficient scan order, and infers that coefficients located outside the predetermined subarea are zero. The first coefficient scan order is so that coefficients outside the predetermined subarea are scanned between two transform coefficients located inside the predetermined subarea. The second coefficient scan order does not scan any coefficient outside the predetermined subarea between scanning the coefficients within the predetermined subarea.