DCT Coefficient Modification for Domain-Compliant Image Down-Conversion
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Solution Overview
Problem
High-definition content providers face challenges in protecting premium services while allowing consumers to access content in reduced resolution formats without violating usage rights, as existing technologies struggle to efficiently transform HD content into domain-compliant reduced resolution without decoding and re-encoding, which is computationally intensive and resource-intensive.
Innovation Solution
A method and system for generating domain-compliant image data by evaluating usage rights and modifying Direct Cosine Transform (DCT) coefficients of encoded HD content to remove disallowable spatial frequencies, allowing for down-conversion to SD or SD-like resolution without fully decoding the content, thereby enabling secure transfer of reduced resolution content while optimizing resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional transcoding methods are used to convert HD content to reduced resolution, then domain compliance is achieved, but computational power requirements increase significantly
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing DCT coefficient magnitude thresholds corresponding to different spatial frequency cutoffs before content processing. When content needs to be converted to a specific resolution, the system simply retrieves the pre-computed threshold table and applies it without performing complex calculations during the actual conversion, thereby reducing computational power requirements while ensuring domain compliance
Solution Approach 2:
The patent changes parameters by working directly with DCT coefficient magnitudes in the frequency domain rather than converting to spatial domain and back. By modifying only the magnitude values of coefficients above the threshold while preserving their phase information, the system achieves resolution conversion with significantly reduced computational complexity compared to traditional transcoding methods
2Productivity
If DCT coefficients are modified without complete decoding, then processing speed increases, but complexity of ensuring usage rights compliance increases
Solution Approach 1:
The patent applies segmentation by separating the content protection mechanism into distinct components: usage rights information is extracted and evaluated independently, DCT coefficient thresholds are pre-computed and stored in separate lookup tables, and the actual coefficient modification uses simple thresholding operations. This segmentation allows each component to be optimized independently, maintaining compliance verification capability while achieving high processing speed through efficient threshold-based filtering
3Reliability
If spatial frequency content is removed to meet usage rights, then usage rights compliance is ensured, but loss of information occurs
Solution Approach 1:
The patent changes parameters by operating in the frequency domain and selectively modifying only the magnitude of DCT coefficients that correspond to spatial frequencies above the allowed threshold. By preserving the phase information of all coefficients and only attenuating the magnitude of high-frequency components, the system ensures usage rights compliance while minimizing information loss and maintaining the essential visual characteristics of the content
Data Source
AI summary
Systems and methods for generating domain-compliant image data. Domain-specific usage rights may be evaluated. The domain-specific usage rights may be associated with the transfer of particular encoded image data to a particular computing system other than the computing system. The domain-specific usage rights may specify maximum allowable spatial frequency content of the particular encoded image data. Domain-compliant image data may be generated by removing particular disallowable spatial frequency content from the encoded image data prior to transfer to the particular computing system.