Selective Transform Coding for Video Text Sharpness
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Solution Overview
Problem
Existing video coding techniques often result in loss of information, particularly when transforming units associated with textual content, leading to blurry textual content during decoding.
Innovation Solution
The proposed solution involves selectively transforming units of video content based on predetermined criteria, such as the difference between highest and lowest pixel values, and rate-distortion constraints, allowing for quantization without transformation to maintain information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If motion-compensation-based video coding schemes are used to compress video content, then the amount of data transferred over the network is reduced, but information loss occurs particularly in textual content leading to blurry appearance
Solution Approach 1:
The patent applies different coding strategies to different regions of the video frame based on content type. Textual content regions are identified and processed differently from general video content, with selective disabling of transform operations in text regions to preserve sharpness and readability while allowing compression in non-text regions.
Solution Approach 2:
The patent dynamically adjusts coding parameters based on the detected content type. When text is detected in a region, transform operations are disabled and alternative coding methods are applied. The coding mode, transform size, and quantization parameters are changed adaptively according to whether the region contains text or general video content.
2Productivity
If transform operations are applied to all video units during encoding, then compression efficiency is improved, but textual content becomes blurry after decoding
Solution Approach 1:
The patent implements region-specific coding where transform operations are selectively applied or disabled based on the local content type. Text regions are identified through various methods (edge detection, character recognition, statistical analysis) and have transform operations disabled to preserve sharp edges and readability, while non-text regions use standard transform-based coding for efficient compression.
Solution Approach 2:
The patent divides the video frame into multiple regions or blocks and applies different coding strategies to each segment. By segmenting the frame and identifying which segments contain text, the system can apply appropriate coding parameters to each segment, maintaining sharpness in text regions while achieving compression in other regions.
3Quantity of substance
If transform and quantization operations are performed on video units, then the amount of data to be transmitted is reduced, but the image quality particularly of textual content deteriorates
Solution Approach 1:
The patent dynamically changes coding parameters based on content analysis. When text is detected in a region, parameters such as transform size, transform type, and quantization step size are adjusted or disabled to preserve text quality. The system selects from multiple coding modes adapted to different content types, changing parameters adaptively rather than using fixed parameters for all regions.
Solution Approach 2:
The patent incorporates feedback mechanisms where the encoder analyzes the content of each video unit or region and adjusts coding operations accordingly. The system evaluates characteristics such as edge density, pixel value distribution, or text detection results and uses this feedback to determine whether to apply transform operations and which coding mode to use, creating a closed-loop adaptive coding system.
Data Source
AI summary
Techniques for selectively transforming one or more coding units when coding video content are described herein. The techniques may include determining whether or not to transform a particular coding unit. The determination may be based on a difference in pixel values of the particular coding unit and/or one or more predefined rate-distortion constraints. When it is determined to not perform a transform, the particular coding unit may be coded without transforming the particular coding unit.