Adaptive Raster Scan Order for HEVC Video Coding
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Solution Overview
Problem
The existing HEVC video coding standard is inefficient for UHD videos with high vertical motion due to the ineffectiveness of horizontal raster scan for prediction and the high on-chip memory requirements for motion estimation and compensation.
Innovation Solution
Adaptive selection between horizontal and vertical raster scan orders based on motion size and coding efficiency, using vertical raster scan for frames with vertical discontinuities and incorporating displacement information for improved bitstream compression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If horizontal raster scan is used for frame coding, then the coding structure is simple and processing is straightforward, but prediction effectiveness deteriorates for frames with vertical discontinuities and large on-chip memory is required for motion estimation and compensation
Solution Approach 1:
The patent applies dynamics by making the raster scan order adaptive rather than fixed. The encoder dynamically selects between horizontal and vertical scan orders based on motion characteristics of the current frame. When vertical motion is detected, vertical scan order is used; otherwise horizontal scan order is used. This dynamic adaptation resolves the contradiction by allowing the system to optimize prediction effectiveness for specific frame types while maintaining simple processing for other cases.
Solution Approach 2:
The patent changes the scanning parameter (scan order) based on motion characteristics. By detecting motion vectors and determining whether vertical motion exceeds a threshold, the system changes the scan order parameter from horizontal to vertical or vice versa. This parameter change allows the coding structure to adapt to different frame types, improving prediction effectiveness without permanently complicating the basic coding structure.
2Ease of operation
If horizontal raster scan is used for UHD videos with large vertical motion, then the coding process is straightforward, but on-chip memory requirements increase significantly for motion estimation and compensation
Solution Approach 1:
The patent uses dynamic selection of scan order to adapt memory requirements to actual motion characteristics. For UHD videos with large vertical motion, the system dynamically switches to vertical scan order, which allows motion estimation and compensation to operate more efficiently with reduced memory buffers. This dynamic adaptation resolves the contradiction by making memory requirements dependent on actual frame characteristics rather than being uniformly high for all UHD content.
Solution Approach 2:
The patent changes the scan order parameter based on motion analysis of UHD frames. When vertical motion vectors exceed a threshold, the system changes from horizontal to vertical scan order, which fundamentally alters how reference frames are accessed during motion compensation. This parameter change reduces the memory buffer size needed for sliding window operations, directly addressing the high memory requirements for UHD videos with vertical motion.
3Reliability
If vertical raster scan is used for frames with vertical discontinuities, then prediction effectiveness improves, but device complexity increases due to adaptive selection and additional processing
Solution Approach 1:
The patent applies dynamics by implementing adaptive scan order selection that activates only when needed. The encoder includes motion detection logic that analyzes motion vectors and determines whether vertical motion threshold is exceeded. This dynamic approach ensures vertical scan order (which improves prediction for vertical discontinuities) is used only when beneficial, while maintaining simple horizontal scan order for other cases, thus limiting the increase in device complexity to only when improvement is achieved.
Solution Approach 2:
The patent changes the scan order parameter based on motion characteristics detected in the frame. The system analyzes motion vectors and changes from horizontal to vertical scan order when vertical motion exceeds a threshold. This conditional parameter change ensures that the more complex vertical scan processing is only activated when it provides prediction improvement, balancing reliability enhancement with controlled device complexity.
4Productivity
If adaptive raster scan order selection is implemented, then coding efficiency improves for various frame types, but processing time and computational complexity increase
Solution Approach 1:
The patent implements dynamic scan order selection that adapts to frame characteristics. The encoder dynamically determines whether vertical or horizontal scan order is more appropriate based on motion analysis. This dynamic approach improves coding efficiency by optimizing for each frame type while the motion vector analysis (which reuses existing motion information) keeps the additional processing time minimal compared to the compression efficiency gains achieved.
Data Source
AI summary
A method and apparatus for frame coding in adaptive raster scan order. The method includes encoding at least one of image or video utilizing input frames and at least one of a data related to the input frame to produce bitstream with raster scan order information and displacement information for producing compressed video bitstream, at decoding time, decoding at least one of the encoded bitstream with raster scan order information and displacement information for producing compressed video bitstream.