Temporal Motion Vector Prediction Using Priority-Based Candidate Selection
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Solution Overview
Problem
Conventional video coding systems face challenges in reducing the bitrate associated with motion vector transmission, particularly in low-bitrate applications, as they often rely on a single candidate for motion vector prediction, which may not be available, leading to inefficiencies in coding efficiency.
Innovation Solution
The proposed method enhances motion vector prediction by using a priority-based approach that considers motion vectors from both past and future reference pictures, selecting predictors from a candidate set based on pre-defined priority orders to increase the availability and accuracy of motion vector prediction, thereby reducing the need for side information and improving coding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional temporal MVP uses a single candidate (co-located motion vector in previous frame), then the method is simple, but the predictor availability is low and coding efficiency is reduced
Solution Approach 1:
The patent segments the motion vector prediction by dividing reference pictures into multiple lists (List 0 and List 1) and further segmenting candidates within each list based on temporal distance. This segmentation allows the system to explore multiple candidate motion vectors from different reference lists rather than relying on a single candidate, thereby improving predictor availability while maintaining a structured and manageable complexity through systematic organization of candidates.
2Measurement precision
If multiple motion vector candidates from multiple reference lists are used, then predictor availability and accuracy improve, but bitrate consumption increases
Solution Approach 1:
The patent implements partial action by selectively constructing candidate sets from multiple reference lists only when beneficial, rather than always using all available candidates. The system evaluates the availability and suitability of candidates from List 0 and List 1, constructing the candidate set dynamically based on what is needed. This approach achieves improved prediction accuracy by using multiple candidates when available, while avoiding excessive bitrate consumption by not forcing the use of all possible candidates in every situation.
Solution Approach 2:
The patent changes the parameter of candidate selection by introducing a priority order based on temporal distance and reference list configuration. Instead of treating all motion vector candidates equally, the system adjusts the selection parameters to prioritize candidates from reference pictures that are temporally closer or more relevant to the current picture. This parameter change allows accurate prediction while controlling bitrate by focusing on the most effective candidates.
3Measurement precision
If side information is transmitted explicitly to inform decoder of predictor type, then prediction accuracy improves, but bandwidth consumption increases
Solution Approach 1:
The patent implements self-service by designing a closed-loop MVP scheme where the predictor is automatically derived at the decoder based on decoded information without requiring explicit side information transmission. The decoder independently reconstructs the same candidate set and selects the same predictor as the encoder by following the same priority order rules. This self-service mechanism achieves accurate prediction while minimizing bandwidth consumption, as no additional side information bits are needed to communicate predictor selection between encoder and decoder.
Data Source
AI summary
An apparatus and method for temporal motion vector prediction for a current block in a picture are disclosed. In the present method, one temporal block in a first reference picture in a first list selected from a list group comprising list 0 and list 1 is determined. When the determined temporal block has at least one motion vector, a candidate set is determined based on the motion vector of the temporal block. The temporal motion vector predictor or temporal motion vector predictor candidate or temporal motion vector or temporal motion vector candidate for the current block is determined from the candidate set by checking a presence of a motion vector pointing to a reference picture in a first specific list in said at least one motion vector, wherein the first specific list is selected from the list group based on a priority order.