Reference Picture List Signaling With One-Bit Inclusion Flags
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Solution Overview
Problem
The redundancy in signaling reference picture handling in HEVC, specifically the use of three bits for temporal_id in Buffer Descriptions, leads to inefficiencies in bit usage and potential bitrate increase.
Innovation Solution
Implementing a one-bit flag to indicate explicitly whether a reference picture should be included in the reference picture list, based on its temporal layer relative to the current picture, reducing redundancy and bit usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If three bits are used for temporal_id in Buffer Description, then reference picture identification is enabled, but bit usage efficiency deteriorates and bitrate increases
Solution Approach 1:
The patent changes the parameter representation from three bits (temporal_id with values 0-7) to a one-bit flag system. This parameter transformation reduces the bit usage from 3 bits per reference picture to 1 bit per reference picture, directly resolving the contradiction between maintaining identification capability and reducing bit usage.
Solution Approach 2:
The patent applies different signaling methods to different reference pictures based on their temporal layer relationships. Instead of uniformly using three bits for all reference pictures, it uses a one-bit flag for pictures where the temporal_id relationship is predictable (current picture's temporal_id >= reference picture's temporal_id), and maintains three-bit signaling only when necessary. This local differentiation optimizes bit usage while preserving identification capability.
2Device complexity
If absolute signaling of reference pictures is implemented, then reference picture handling is simplified, but bit usage increases due to explicit Buffer Description signaling
Solution Approach 1:
The patent transforms the signaling approach from absolute Buffer Description (listing all reference pictures explicitly) to a differential approach using one-bit flags. This parameter change in the signaling mechanism maintains the simplified reference picture handling while reducing the actual bit usage by exploiting the predictable temporal_id relationships in scalable video coding.
Solution Approach 2:
Instead of signaling complete Buffer Descriptions for all reference pictures, the patent uses partial signaling with one-bit flags only where necessary. This partial action approach reduces bitrate by avoiding redundant signaling of reference pictures whose temporal_id relationships can be inferred from the scalable video coding structure.
3Measurement precision
If temporal_id is signaled for each reference picture, then reference picture temporal layer identification is enabled, but redundancy increases and encoding efficiency deteriorates
Solution Approach 1:
The patent changes the temporal_id signaling parameter from explicit three-bit values to implicit one-bit flag representation. This parameter transformation reduces signal redundancy by 66% (from 3 bits to 1 bit per reference picture) while maintaining temporal layer identification precision through the one-bit flag that indicates whether the reference picture should be included in the reference picture list based on temporal layer relationships.
Data Source
AI summary
An encoder is configured to encode a representation of a current picture of a video stream of multiple pictures. The encoder is further configured to encode, for each of a plurality of reference pictures included in a buffer description for the current picture, a respective one-bit flag according to one of two available values for the one-bit flag. The two available values for the one-bit flag include a first value explicitly indicating to a decoder to include the reference picture in a reference picture list for decoding the current picture. The two available values for the one-bit flag further include a second value explicitly indicating to the decoder not to include the reference picture in the reference picture list for decoding the current picture. The encoder is further configured to output the representation of the current picture and the one-bit flags.