Merge Flag Coding Decoupled From Candidate Lists in Video Parsing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing merge mode in HEVC video coding standards, such as HM2.0, incurs significant overhead and error sensitivity due to conditional encoding of the merge flag, which depends on the size of the merging candidate list, making bit stream parsing inefficient and error-prone.
Innovation Solution
Decoupling the encoding of the merge flag from the merging candidate list size, ensuring it is always encoded for inter-predicted PUs not using skip mode, and adding a zero motion vector candidate to guarantee a non-empty list, thereby making bit stream parsing independent of the candidate list construction and more resilient to errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the merge flag encoding is conditionally applied based on merging candidate list size, then coding efficiency is improved, but parsing overhead increases and error resilience deteriorates
Solution Approach 1:
The patent applies preliminary action by always encoding the merge flag for inter-predicted PUs regardless of the merging candidate list size. This eliminates the need for conditional logic during parsing, as the flag is consistently present in the bitstream. The decoder can reliably parse the merge flag without needing to first construct and evaluate the merging candidate list, thereby reducing parsing overhead and improving error resilience.
2Productivity
If the merge flag encoding is conditionally applied based on merging candidate list size, then coding efficiency is improved, but error resilience deteriorates
Solution Approach 1:
By always encoding the merge flag in advance for inter-predicted PUs, the patent ensures that the flag is consistently available in the bitstream regardless of the merging candidate list construction. This preliminary encoding action eliminates the risk of missing flags during decoding and reduces error propagation, thereby improving error resilience while maintaining coding efficiency.
3Measurement precision
If the merging candidate list is constructed before merge flag encoding, then accurate mode selection is achieved, but parsing efficiency deteriorates
Solution Approach 1:
The patent segments the encoding process by separating the merge flag encoding from the merging candidate list construction. The merge flag is encoded independently and consistently for all inter-predicted PUs, while the merging candidate list construction remains a separate decoding step. This segmentation allows the parser to efficiently process the always-present merge flag without being blocked by candidate list construction, thereby improving parsing efficiency while maintaining mode selection accuracy.
Data Source
AI summary
Methods and apparatus for parsing friendly and error resilient merge flag coding in video coding are provided. In some methods, in contrast to merging candidate list size dependent coding of the merge flag in the prior art, a merge flag is always encoded in the encoded bit stream for each inter-predicted prediction unit (PU) that is not encoded using skip mode. In some methods, in contrast to the prior art that allowed the merging candidate list to be empty, one or more zero motion vector merging candidates formatted according to the prediction type of the slice containing a PU are added to the merging candidate list if needed to ensure that the list is not empty and/or to ensure that the list contains a maximum number of merging candidates.