CABAC Context Initialization Using Indexed Probability States
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Solution Overview
Problem
Existing context adaptive entropy coding techniques, such as CABAC, require significant information for initializing contexts, leading to inefficiencies in data compression and increased complexity due to the use of direct initialization parameters, resulting in less accurate initial probabilities and higher bit storage requirements.
Innovation Solution
The proposed techniques reduce information storage and transmission by using initialization parameter index values to determine context states and probabilities, allowing for more accurate initial probabilities and reduced complexity through methods like using slope and intersection index values, and incorporating temporal layer information for context initialization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If direct initialization parameters are used for context adaptive entropy coding, then the coding process can be implemented, but the complexity increases and more information storage is required
Solution Approach 1:
The patent uses index values to reference initialization parameters from a predefined table rather than storing and processing the full parameter sets. Each context is initialized by copying parameters from the table using the index as a key, significantly reducing the amount of information that needs to be stored and transmitted while maintaining the same initialization accuracy.
2Reliability
If direct initialization parameters are used for context adaptive entropy coding, then the coding process can be implemented, but the bit storage requirements increase
Solution Approach 1:
Instead of storing complete initialization parameter sets for each context, the patent stores compact index values that reference a shared initialization parameter table. This copying approach reduces bit storage requirements from potentially hundreds of bits per context to just a few bits per index value, while the actual parameter data is shared across multiple contexts.
3Quantity of substance
If initialization parameter index values are used, then the information storage and transmission is reduced, but additional processing steps are required
Solution Approach 1:
The patent pre-organizes initialization parameters in a structured table format with predefined indices before the actual coding process begins. This preliminary arrangement allows the coding process to simply look up and use the pre-computed parameters via index values, avoiding the need to compute initialization parameters on-the-fly during encoding or decoding operations.
Data Source
AI summary
In one example, an apparatus for context adaptive entropy coding may include a coder configured to determine one or more initialization parameters for a context adaptive entropy coding process based on one or more initialization parameter index values. The coder may be further configured to determine one or more initial context states for initializing one or more contexts of the context adaptive entropy coding process based on the initialization parameters. The coder may be still further configured to initialize the contexts based on the initial context states. In some examples, the initialization parameters may be included in one or more tables, wherein, to determine the initialization parameters, the coder may be configured to map the initialization parameter index values to the initialization parameters in the tables. Alternatively, the coder may be configured to calculate the initialization parameters using the initialization parameter index values and one or more formulas.