Subblock Merge Motion Vector List Length in Video Prediction
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Solution Overview
Problem
Existing video coding technologies lack a feasible method to determine the maximum length of a candidate motion vector list in subblock merge mode, which affects encoding/decoding performance.
Innovation Solution
A method and apparatus for determining the maximum length of a candidate motion vector list in a subblock merge mode by parsing specific indicators from a bitstream, considering the presence or absence of advanced temporal and planar motion vector prediction modes, and using predefined formulas to calculate the list length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If subblock merge mode is introduced to improve prediction accuracy, then encoding/decoding performance is improved, but the complexity of determining candidate motion vector list length increases
Solution Approach 1:
The patent introduces a parameter `sps_sbtmvp_enabled_flag` that can be parsed from the bitstream to control whether advanced temporal motion vector prediction is enabled. By changing this parameter's state (enabled/disabled), the system adjusts the candidate motion vector list length according to predefined formulas, thereby managing complexity while maintaining prediction accuracy improvements from subblock merge mode
2Reliability
If advanced temporal motion vector prediction mode is added to enhance prediction capability, then encoding/decoding performance is improved, but the bitstream parsing complexity increases
Solution Approach 1:
The patent performs preliminary action by parsing the `sps_sbtmvp_enabled_flag` indicator before determining the candidate motion vector list length. This flag is extracted from the bitstream in advance, allowing the system to pre-determine which formula to apply (Formula 1 if enabled, Formula 2 if disabled) when calculating the list length, thereby simplifying the overall parsing process
3Reliability
If planar motion vector prediction mode is considered to improve prediction accuracy, then encoding/decoding performance is improved, but the determination of candidate motion vector list length becomes more complex
Solution Approach 1:
The patent uses the parameter `sps_sbtmvp_enabled_flag` to control whether planar motion vector prediction is available. When this flag is set to enable advanced temporal motion vector prediction, the system applies a different formula (Formula 1) to calculate the candidate motion vector list length compared to when it is disabled (Formula 2). This parameter-based approach manages complexity by selectively applying different calculation rules based on the enabled prediction modes
Data Source
AI summary
A video picture prediction method and apparatus are provided, to provide a manner of determining a maximum length of a candidate motion vector list corresponding to a subblock merge mode. The method includes: parsing a first indicator from a bitstream; if the first indicator indicates that a candidate mode used to inter predict the to-be-processed block includes an affine mode, parsing a second indicator from the bitstream, where the second indicator is used to indicate a maximum length of a first candidate motion vector list, and the first candidate motion vector list is constructed for the to-be-processed block, a subblock merge prediction mode is used for the to-be-processed block; and determining the maximum length of the first candidate motion vector list based on the second indicator.