Adaptive Motion Vector Difference Resolution for Video Decoding
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Solution Overview
Problem
Existing video coding technologies face inefficiencies in handling motion vector differences during inter-prediction, particularly in determining the appropriate pixel resolution for motion vector differences, which affects compression efficiency and decoding accuracy.
Innovation Solution
The method involves determining the pixel resolution for motion vector differences based on predefined magnitude ranges and extracting additional information from the video stream to decode inter-predicted video blocks accurately, using integer or fractional pixel resolutions as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a fixed pixel resolution is used for motion vector difference, then the decoding process is simple, but the compression efficiency and decoding accuracy are insufficient
Solution Approach 1:
The patent implements adaptive pixel resolution for motion vector difference by dynamically selecting between 1/4-pel and 1-pel resolutions based on the magnitude range of the motion vector difference. This dynamic adaptation allows the system to optimize compression efficiency for each specific case while managing decoding complexity through predefined resolution selection rules.
Solution Approach 2:
The patent changes the pixel resolution parameter of motion vector difference based on the magnitude range. When the motion vector difference magnitude exceeds a threshold, 1-pel resolution is used; otherwise, 1/4-pel resolution is applied. This parameter adaptation resolves the contradiction by adjusting resolution to match the actual motion characteristics.
2Measurement precision
If high pixel resolution is used for motion vector difference, then decoding accuracy is improved, but bit requirements increase
Solution Approach 1:
The patent applies different pixel resolutions locally based on the motion vector difference magnitude. For small motion vector differences (below threshold), 1/4-pel resolution provides sufficient accuracy with fewer bits. For large motion vector differences (above threshold), 1-pel resolution ensures decoding accuracy. This local quality adaptation resolves the contradiction between precision and bit requirements.
Solution Approach 2:
The patent dynamically changes the pixel resolution parameter based on the motion vector difference magnitude range, selecting 1/4-pel for small magnitudes and 1-pel for large magnitudes. This adaptive parameter selection optimizes the balance between decoding accuracy and bit requirements for each specific case.
3Productivity
If adaptive pixel resolution is implemented for motion vector difference, then compression efficiency and decoding accuracy are enhanced, but the device complexity increases
Solution Approach 1:
The patent implements dynamic pixel resolution selection based on motion vector difference magnitude ranges, enhancing video coding performance by adapting to local motion characteristics. The complexity is managed through predefined threshold-based decision rules that guide the selection between 1/4-pel and 1-pel resolutions, making the adaptive process computationally feasible.
Data Source
AI summary
This disclosure relates to encoding and decoding of motion vector difference for inter-predicting a video block. An example is disclosed for decoding an inter-predicted video block of a video stream. The method may include determining that a motion vector associated with the inter-predicted video block is encoded as a motion vector difference (MVD) between the motion vector and a reference motion vector; obtaining, from the video stream, an indication of a magnitude range of the MVD among a plurality of predefined magnitude ranges for motion vector differences; determining a pixel resolution for the MVD according to the magnitude range; identifying additional MVD information in the video stream based on the pixel resolution; extracting the additional MVD information from the video stream; and decoding the inter-predicted video block based on the pixel resolution, the additional MVD information, the reference motion vector, and a reference frame associated with the motion vector.