Temporal Motion Vector Flag Inference for Video Compression
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Solution Overview
Problem
In video compression systems, particularly in HEVC, the overhead of encoding and decoding temporal motion vector flags and associated information can be significant, as existing methods require explicit signaling of these flags in the bitstream, which increases data complexity and reduces efficiency.
Innovation Solution
The proposed solution involves a method where the decoder infers the default value of the temporal motion vector flag if it is not explicitly present in the bitstream, allowing for reduced overhead by omitting the flag's encoding and using default values for temporal motion vector prediction, thereby simplifying the encoding and decoding processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temporal motion vector flags are explicitly signaled in the bitstream, then motion vector prediction accuracy is improved, but bitstream overhead increases
Solution Approach 1:
Instead of always signaling the temporal MVP flag explicitly, the patent inverts the approach by using default values and only signaling when deviation from default is needed. The flag is inferred as 0 (disabled) by default, and only explicitly signaled when set to 1 (enabled), thereby reducing bitstream overhead while maintaining prediction accuracy when needed.
Solution Approach 2:
The patent changes the signaling parameter from a fixed explicit flag to a conditional inference mechanism. By modifying how the flag is represented (from always-encoded to conditionally-inferred), the system reduces the average bit cost while preserving the ability to achieve high prediction accuracy when temporal MVP is beneficial.
2Measurement precision
If temporal motion vector information is always encoded, then decoding accuracy is improved, but computational complexity increases
Solution Approach 1:
The patent applies partial action by encoding temporal motion vector information only when necessary rather than always. The temporal MVP flag is conditionally signaled based on whether it differs from the default value, providing decoding accuracy improvements only in cases where temporal prediction is beneficial, while avoiding unnecessary computational overhead in other cases.
3Reliability
If the flag enable_temporal_mvp_flag is always present in the bitstream, then decoder reliability is improved, but data transmission efficiency decreases
Solution Approach 1:
The patent extracts and removes redundant flag signaling from the bitstream. By inferring the default value of enable_temporal_mvp_flag as 0 when not explicitly signaled, the system eliminates unnecessary data transmission while maintaining decoder reliability through well-defined fallback behavior. This extraction of redundant information directly improves transmission efficiency.
Data Source
AI summary
In one embodiment, a method determines whether a flag that controls whether a temporal motion vector is used for slice is present in an encoded bitstream. If the flag is present, the method determines a value for the flag, and if the flag is not present, the method infers that the value for the flag is a default value. Then, the method evaluates whether to determine a collocated reference picture in decoding the slice from the encoded bitstream based on the value of the flag.