Intra Prediction Mode Signaling With Split Non-Selected Lists
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Solution Overview
Problem
Existing video coding standards face challenges in achieving high coding efficiency for intra prediction due to fixed and non-adaptive signaling of intra prediction modes, leading to increased computational complexity and signaling overhead.
Innovation Solution
An apparatus and method for determining an intra prediction mode based on a most probable modes list, a selected modes list, and a non-selected modes list, where the non-selected modes are divided into two portions to optimize bit usage, with modes closer to the probable and selected lists using fewer bits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the number of intra prediction modes is increased to improve coding precision, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent segments the non-selected modes list into two portions: a first portion with modes close to the probable and selected lists, and a second portion with modes far from them. This segmentation allows differential bit allocation, using fewer bits for the first portion and more bits for the second portion, thereby improving coding precision while managing device complexity through structured organization of prediction modes
Solution Approach 2:
The patent applies local quality by assigning different bit lengths to different portions of the non-selected modes list based on their proximity to probable and selected modes. Modes in the first portion (closer to probable/selected lists) use fewer bits, while modes in the second portion (farther away) use more bits, optimizing the balance between coding precision and computational complexity
2Manufacturing precision
If the number of intra prediction modes is increased to improve manufacturing precision, then manufacturing precision is improved, but loss of information increases
Solution Approach 1:
The patent segments the non-selected modes list into two portions to enable differential signaling. The first portion (modes close to probable and selected lists) is signaled with fewer bits, while the second portion (modes far from these lists) is signaled with more bits. This segmentation reduces overall signaling overhead compared to uniform signaling, while still maintaining the ability to represent all 65+ intra prediction modes with sufficient precision
Solution Approach 2:
The patent changes the parameter of bit allocation from a uniform value to a variable value based on the proximity of modes to probable and selected lists. By adjusting the number of bits required to signal each mode according to its position in the non-selected modes list, the patent reduces signaling overhead while preserving coding precision
3Ease of operation
If uniform bit allocation is used for all non-selected modes, then ease of operation is improved, but loss of information increases
Solution Approach 1:
The patent segments the non-selected modes list into two portions with different bit allocation strategies. The first portion uses a simplified signaling approach with fewer bits for modes close to probable and selected lists, while the second portion uses a more detailed signaling approach with more bits for modes far from these lists. This segmentation maintains operational simplicity for common cases while reducing overall signaling overhead
Solution Approach 2:
The patent changes the bit allocation parameter from a uniform value to a conditional value based on the mode's position in the non-selected modes list. By dynamically adjusting the number of bits required to signal each mode, the patent optimizes the balance between signaling simplicity and overhead reduction
Data Source
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AI summary
The invention relates to an apparatus (100) configured to determine an adopted intra prediction mode on the basis of a most probable modes list, a selected modes list and a non-selected modes list having a first portion and a second portion, wherein the adopted intra prediction mode is one of a plurality of intra prediction modes comprising a plurality of angular intra prediction modes for predicting sample values of a current picture block (103), wherein the apparatus (100) comprises: a processing unit (101) configured to generate the first portion of the non-selected modes list by including one or more angular intra prediction modes determined on the basis of the most probable modes list and the selected modes list such that the one or more angular intra prediction modes of the first portion of the non-selected modes list are close to a respective angular intra prediction mode of the most probable modes list and the selected modes list, wherein the processing unit (101) is further configured to determine the adopted intra prediction mode, in case the adopted intra prediction mode is part of the first portion of the non-selected modes list, using less bits than in case the adopted intra prediction mode is part of the second portion of the non-selected modes list.