Inverse Orthogonal Transform Unit for Image Encoding Efficiency
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Solution Overview
Problem
Existing image encoding techniques, such as MDDT, face challenges in increasing encoding efficiency due to difficulties in optimizing transforms based on intra prediction directions.
Innovation Solution
An image decoding and encoding apparatus that performs orthogonal transforms on prediction error data using bases specific to block locations within a macroblock, allowing for optimized inverse orthogonal transforms and improved encoding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If MDDT technique is used to switch transform methods according to intra prediction directions, then encoding efficiency can be improved, but the complexity of optimizing transforms increases
Solution Approach 1:
The patent divides the macroblock into multiple transform blocks and applies different transform methods to each block based on its specific characteristics and prediction direction. This segmentation allows the system to optimize encoding efficiency for each block independently without requiring complex global optimization, thus resolving the contradiction between improving encoding efficiency and reducing transform optimization complexity.
Solution Approach 2:
The patent applies different transform methods (e.g., DCT, ADCT, or other orthogonal transforms) to different transform blocks within the same macroblock based on their local characteristics such as prediction direction and block location. This local quality approach enables optimized encoding for each block while maintaining overall system simplicity, as each block is processed according to its specific needs rather than requiring complex global optimization.
2Productivity
If H.264/AVC is used to achieve higher encoding efficiency, then compression rate improves, but decoding calculation amount increases
Solution Approach 1:
The patent changes the transform parameters and methods dynamically based on the prediction direction and block location within the macroblock. By selecting appropriate orthogonal transforms (DCT, ADCT, or other variants) for each transform block, the system achieves high encoding efficiency comparable to H.264/AVC while using simpler decoding calculations, thus resolving the contradiction between encoding efficiency and decoding computational burden.
Data Source
AI summary
An encoded bit stream is processed by a lossless decoding unit, an inverse quantization unit, and an inverse orthogonal transform unit in this order, to obtain orthogonally transformed coefficient data and encoding parameter information. The inverse orthogonal transform unit performs an inverse orthogonal transform on the coefficient data by using bases that are set beforehand in accordance with the locations of transform blocks in a macroblock indicated by the encoding parameter information. In this manner, prediction error data is obtained. An intra prediction unit generates predicted image data. An addition unit adds the predicted image data to the prediction error data, to decode image data. By using bases that are set in accordance with the locations of transform blocks, an optimum inverse orthogonal transform can be performed, and encoding efficiency can be increased.