Motion Vector Clipping for Video Decoding Memory Reduction
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Solution Overview
Problem
Existing video coding/decoding methods require large memory space and bandwidth for storing and accessing motion vectors, especially in environments with limited memory, such as portable terminals.
Innovation Solution
The method involves clipping and magnitude scaling motion vectors of reference pictures within a predetermined range, storing them in block units, and using these clipped motion vectors for inter-prediction decoding, thereby reducing memory requirements and access bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If motion vectors are stored with full precision and range, then video decoding accuracy is maintained, but memory space and access bandwidth requirements increase significantly
Solution Approach 1:
The patent applies parameter changes by clipping motion vectors to a predetermined range and applying magnitude scaling. Motion vectors are transformed from their original full-range values to scaled values within a limited range (e.g., -128 to +127), reducing the number of bits required for storage while maintaining sufficient decoding accuracy for practical video applications.
Solution Approach 2:
The patent uses partial action by storing motion vectors at reduced precision for most cases, while still maintaining adequate video quality. The clipping and scaling operations apply partial transformation to motion vector data, keeping only the most significant components that contribute to visual quality, thereby reducing memory requirements without excessive loss of functionality.
2Quantity of substance
If motion vectors are clipped and magnitude scaled to reduce memory usage, then memory space and bandwidth are reduced, but motion vector precision is degraded
Solution Approach 1:
The patent transforms motion vector parameters through clipping to a fixed range and magnitude scaling. This parameter transformation reduces the dynamic range of motion vectors from potentially very large values to a manageable range, enabling compact storage while preserving the essential motion information needed for video decoding.
Solution Approach 2:
The patent creates a simplified copy of the original motion vector data through clipping and scaling operations. Instead of storing full-precision motion vectors, the system creates a reduced-precision representation that captures the dominant motion characteristics, sufficient for reconstructing video frames with acceptable quality.
3Reliability
If full-precision motion vectors are used for inter-prediction decoding, then decoding accuracy is maintained, but access bandwidth requirements increase
Solution Approach 1:
The patent changes the parameter representation of motion vectors by applying clipping and magnitude scaling. This transformation reduces the data width required for motion vector storage and transmission, thereby decreasing the bandwidth needed for accessing motion vector data during video decoding operations while maintaining sufficient accuracy for practical purposes.
Data Source
AI summary
The present invention relates to image processing, and more particularly, to a video coding/decoding method using a clipped motion vector and an apparatus thereof. An embodiment of the present invention relates to a method of decoding an image. The method includes clipping a motion vector of a reference picture in a predetermined dynamic range to generate a clipped motion vector, storing the clipped motion vector in a buffer, deriving a motion vector of a coding treeblock using the motion vector stored in the buffer, and performing inter prediction decoding process using the motion vector of the coding treeblock. According to the exemplary embodiment of the present invention, a size of a memory required for storing motion vectors may be reduced.