Interlaced Video Scan Patterns for Entropy Coding Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing video compression techniques, such as those in Windows Media Video 8 and 9, H.261, MPEG, and H.264 standards, are not well-suited for common configurations of non-zero transform coefficients in 8×4 and 4×8 inter-coded blocks, leading to sub-optimal re-ordering of transform coefficients and inefficiencies in entropy coding for both progressive and interlaced video.
Innovation Solution
Adopting scan patterns that bias the vertical direction for 4×4, 8×4, and 4×8 blocks, prioritizing the scanning of DC and low-frequency AC coefficients to improve the re-ordering of transform coefficients, thereby enhancing the efficiency of entropy coding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If existing video compression techniques are used, then video compression is achieved, but the re-ordering of transform coefficients is sub-optimal leading to inefficiencies in entropy coding
Solution Approach 1:
The patent changes the scanning parameter by introducing direction flags (scan_direction_8x4, scan_direction_4x8) that control whether to apply progressive or interlaced scan patterns. This allows the system to adapt the coefficient re-ordering strategy based on the video content type, improving entropy coding efficiency without requiring multiple complex dedicated systems.
Solution Approach 2:
The patent implements dynamic selection of scan patterns based on the interlaced field indicator and block type. The decoder dynamically switches between progressive scan and interlaced scan modes, allowing the re-ordering process to adapt to different video content characteristics, thereby optimizing compression efficiency for both progressive and interlaced video.
2Productivity
If scan patterns are optimized for interlaced video, then compression efficiency improves by up to 9%, but compatibility with existing progressive video decoding may be affected
Solution Approach 1:
The patent creates a universal decoding mechanism that handles both progressive and interlaced video formats through a single decoder implementation. By using the interlaced field indicator to select between different scan patterns, the system achieves multi-functionality, maintaining compatibility with existing progressive video while adding optimized support for interlaced video.
Solution Approach 2:
The decoder dynamically adapts its behavior based on the video content type indicated by the interlaced field indicator. When processing interlaced video, it applies interlaced-specific scan patterns to achieve up to 9% compression efficiency improvement, while automatically switching to progressive scan patterns for standard progressive video, ensuring broad format compatibility.
3Quantity of substance
If transform coefficients are re-ordered using existing patterns, then decoding is performed, but the count of coefficients before the last non-zero value is reduced insufficiently
Solution Approach 1:
The patent applies different scanning strategies tailored to specific block types (8x4, 4x8, 8x8) and video formats (progressive, interlaced). By optimizing the scan pattern locally for each block type and format combination, the system effectively groups non-zero coefficients together, reducing the count of coefficients processed in entropy coding and improving coding efficiency.
Solution Approach 2:
The patent changes the scanning order parameter based on the interlaced field indicator and block dimensions. For interlaced video, it applies scan patterns specifically designed to match the coefficient distribution characteristics of interlaced fields, thereby reducing the number of coefficients that need to be processed and improving entropy coding efficiency.
Data Source
AI summary
Tools and techniques for applying scan patterns during encoding and decoding of interlaced video are described. For example, a video decoder scans transform coefficients from a one-dimensional array to a two-dimensional block according to a scan pattern. The block is 4×4, and the scan pattern biases the vertical direction by starting with the DC coefficient and three AC coefficients of the lowest horizontal frequency. Or, the block is 8×4, and the scan pattern biases the vertical direction by starting with the DC coefficient and three AC coefficients of the lowest horizontal frequency. Or, the block is 4×8, and the scan pattern biases the horizontal direction for the lowest frequency AC coefficients in the horizontal and vertical directions but biases the vertical direction for at least some other AC coefficients. A corresponding video encoder applies the scan patterns to scan transform coefficients from two-dimensional blocks to one-dimensional arrays.