Adaptive Motion Vector Resolution for Video Coding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current video coding technologies face inefficiencies due to mismatched motion vector resolutions between the current and reference pictures, leading to suboptimal temporal motion vector prediction and deblocking processes, especially when adaptive motion vector resolution is applied, causing resolution mismatches and bit width limitations.
Innovation Solution
The method involves adjusting motion vector prediction by shifting and clipping motion vectors based on their resolution, ensuring consistent resolution across all blocks within a slice or sequence, and modifying the deblocking process to accommodate different pixel resolutions, thereby aligning motion vector resolutions and improving prediction accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If adaptive motion vector resolution is applied with different resolutions for current and reference pictures, then coding efficiency is improved for different video content types, but resolution mismatch occurs between motion vectors causing prediction errors
Solution Approach 1:
The patent changes the resolution parameter of motion vectors dynamically based on content type. It introduces a mechanism to detect whether the current picture uses integer or fractional pixel resolution and adjusts the reference motion vector resolution accordingly, allowing the system to optimize for screen content (integer) or natural video (fractional) while maintaining prediction accuracy through resolution matching.
Solution Approach 2:
The patent implements dynamic resolution adaptation where the motion vector resolution is not fixed but changes based on the picture type and content characteristics. The system dynamically selects between integer and fractional pixel resolutions for motion vectors, and dynamically adjusts reference motion vectors from previous pictures to match the current resolution requirement.
2Quantity of substance
If motion vectors are clipped to fixed bit width for storage, then memory usage is reduced, but precision is lost due to clipping
Solution Approach 1:
The patent applies different precision levels to different motion vectors based on their specific requirements. Instead of uniformly clipping all motion vectors to a fixed bit width, it maintains higher precision for motion vectors that require it (fractional pixel resolutions) while using lower precision for integer pixel motion vectors, optimizing the balance between memory usage and precision.
3Productivity
If temporal motion vector prediction uses reference motion vectors from pictures with different resolution, then temporal redundancy is exploited, but prediction accuracy deteriorates due to resolution mismatch
Solution Approach 1:
The patent performs preliminary resolution matching before applying temporal motion vector prediction. It detects the resolution type of the current picture in advance and pre-adjusts the reference motion vectors from previous pictures to match the current resolution requirements, ensuring that the temporal prediction operates on matched resolutions and maintains accuracy.
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A method of MVP (motion vector prediction) for video coding with adaptive motion vector resolution is disclosed. According to the method, the MVP coding is applied to the current MV or the current MV is stored depending on the current MV resolution, the reference MV resolution, or both the current MV resolution and the reference MV resolution. In one embodiment, when the current MV resolution corresponds to integer pixel resolution, MVP coding is then applied to the current MV using a modified temporal MV as a motion vector predictor for the current MV, where the modified temporal MV is generated by right-shifting the temporal MV. In another embodiment, when the current MV resolution corresponds to integer pixel resolution, the current MV is left-shifted before it is stored in a memory.