Video Decoder Motion Vector Candidate Reordering for Compression Efficiency
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Solution Overview
Problem
Existing video compression technologies face inefficiencies in encoding and decoding processes due to complex relationships between video quality, data usage, encoding complexity, sensitivity to errors, and the need for improved motion compensation, particularly in handling local and global motion within video frames.
Innovation Solution
Implementing a decoder that constructs and reorders a motion vector candidate list with global motion vectors first, reducing the need for signaling motion vector differences by leveraging common motion across blocks within a frame, thereby improving compression efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If motion vector candidates are processed in conventional order without reordering, then the decoding process is simple, but compression efficiency is reduced due to unnecessary signaling of motion vector differences
Solution Approach 1:
The patent applies preliminary action by reordering motion vector candidates before processing. Specifically, the motion vector candidate list is reordered such that candidates with smaller indices (which correspond to blocks with more similar motion characteristics) are processed first. This preliminary reordering enables the decoder to leverage temporal and spatial correlation more effectively, reducing the need to signal motion vector differences for all candidates and thereby improving compression efficiency without significantly increasing decoding complexity
2Reliability
If all motion vector differences are signaled explicitly, then motion compensation accuracy is maintained, but bit rate increases
Solution Approach 1:
The patent applies local quality by differentiating the treatment of motion vector candidates based on their spatial and temporal characteristics. Instead of uniformly signaling all motion vector differences, the system identifies and processes candidates with similar motion characteristics (local regions in the candidate list) differently from those with dissimilar motion. This selective approach maintains motion compensation accuracy for critical candidates while reducing redundant signaling for similar candidates, thereby lowering the overall bit rate
3Productivity
If motion vectors are processed without considering spatial and temporal correlation, then the processing algorithm is simple, but compression efficiency is reduced
Solution Approach 1:
The patent applies merging by combining spatial and temporal correlation information into a unified reordering strategy. The motion vector candidate list is reordered by considering both spatial proximity (neighbors in the current frame) and temporal similarity (motion characteristics from reference frames). This merged approach allows the decoder to group together candidates that are similar in both space and time, enabling more efficient differential encoding and improving compression efficiency without requiring separate processing stages for spatial and temporal correlations
Data Source
AI summary
A decoder includes circuitry configured to receive a bitstream; construct, for a current block, a motion vector candidate list including a motion vector candidate having motion information that characterizes a global motion vector; reorder the motion vector candidate list such that the motion vector candidate having the motion information that characterizes the global motion vector is first in the reordered motion vector candidate list; and reconstruct pixel data of the current block and using the reordered motion vector candidate list. Related apparatus, systems, techniques and articles are also described.