Image Decoding Reference Picture Lists Using Ordered POC Differences
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Solution Overview
Problem
Existing video compression techniques face challenges in effectively signaling video information, particularly for inter prediction and constructing reference picture lists, leading to increased transmission overheads and complexity.
Innovation Solution
The method involves arranging POC information elements of reference pictures in a specific order, with previous pictures before the current picture in descending order and subsequent pictures in ascending order, and using POC differences and signs to efficiently signal reference picture information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If reference picture information is transmitted without specific ordering, then all reference pictures can be signaled, but transmission overhead increases and decoding complexity increases
Solution Approach 1:
The reference picture list is segmented into two separate lists: L0 for short-term reference pictures and L1 for long-term reference pictures. This segmentation allows the decoder to process different types of reference pictures separately, reducing overall decoding complexity while maintaining complete reference picture information
Solution Approach 2:
The patent applies preliminary ordering rules to arrange reference pictures in each list before transmission. Short-term reference pictures are ordered by POC in ascending order, and long-term reference pictures are ordered by POC in descending order. This preliminary organization reduces the computational burden during decoding operations
2Ease of manufacture
If reference pictures are arranged in arbitrary order, then signaling is simpler, but inter prediction efficiency decreases
Solution Approach 1:
Different ordering strategies are applied to different segments of the reference picture list based on their temporal characteristics. Short-term reference pictures (L0) use ascending POC order to maintain temporal proximity, while long-term reference pictures (L1) use descending POC order. This local quality differentiation optimizes inter prediction efficiency for each segment type
Solution Approach 2:
The patent implements dynamic reference picture list management where the ordering and composition of reference pictures can change based on picture type (I, P, or B pictures) and temporal relationships. This dynamic approach maintains signaling simplicity while adapting to different prediction scenarios to preserve inter prediction efficiency
3Adaptability or versatility
If all reference pictures are included in a single list, then reference picture availability is maximized, but transmission overhead increases
Solution Approach 1:
The reference picture list is divided into two separate lists (L0 and L1) with distinct purposes: L0 for short-term reference pictures and L1 for long-term reference pictures. This segmentation reduces transmission overhead by allowing selective use of reference pictures based on picture type and prediction needs, while still maintaining access to all available reference pictures when required
Solution Approach 2:
The dual-list structure provides universal reference picture availability by enabling the decoder to select from both short-term and long-term reference pictures depending on the prediction requirements. Each list serves multiple functions: L0 provides recent reference pictures for P and B pictures, while L1 provides historical reference pictures for various picture types, achieving versatile reference picture access with reduced overhead
Data Source
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AI summary
A decoding apparatus for image decoding is disclosed, the decoding apparatus comprising a memory and at least one processor connected to the memory. The at least one processor configured to: obtain picture order count, POC, information in a slice header; derive POC values for reference pictures based on the POC information; construct a reference picture list based on the POC values of the reference pictures; and perform an inter prediction on a current block based on the reference picture list, to derive a predicted sample of the current block. The POC information in the slice header includes POC difference value information. A POC value of an i-th reference picture is derived based on a POC difference derived from the POC difference value information. The reference pictures subsequent to a current picture in POC order are ordered in ascending order. For the reference pictures subsequent to the current picture in the POC order, the POC difference represents a difference between a POC value of the current picture and a POC value of the i-th reference picture when i is equal to 0, and the POC difference represents a difference between the POC value of the i-th reference picture and a POC value of an (i-1)-th reference picture when i is greater than 0. The reference pictures with the POC values greater than the POC value of the current picture are ordered in ascending order of the POC values for the reference pictures.