Variable-Length Code Decoding with Multi-Table Bit-Length Control
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Solution Overview
Problem
Existing variable length code decoding methods require attention to common bits, leading to increased table size and processing delays, as they cannot adjust bit length based on the trade-off between table size and processing performance.
Innovation Solution
A variable length code decoding device that uses multiple decoding process tables with a flag indicating completion or continuation, allowing adjustment of bit length referenced from the code word, reducing unnecessary table entries and optimizing table size and processing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed bit length is used for table reference in variable length code decoding, then the decoding process is simplified, but the table size increases and processing performance deteriorates
Solution Approach 1:
The patent applies dynamics by making the bit length for table reference adjustable rather than fixed. The decoding device dynamically selects the bit length based on the specific code word being decoded, allowing optimization between table size and processing speed for each decoding operation. This resolves the contradiction by enabling the system to adapt the reference bit length to match the actual code structure, improving productivity without permanently increasing device complexity.
Solution Approach 2:
The patent changes the parameter of bit length for table reference from a fixed value to a variable parameter. By allowing the bit length to be adjusted based on the code word characteristics and the trade-off between table size and processing speed, the system can optimize decoding performance. This parameter change enables flexible adaptation to different coding scenarios, resolving the contradiction between simplified processing and improved productivity.
2Productivity
If the bit length for table reference is increased, then fewer table references are needed, but the table size increases exponentially
Solution Approach 1:
The patent uses dynamics by making the reference bit length adjustable rather than fixed at a high value. This allows the system to increase the bit length when decoding speed is prioritized (reducing table references) or decrease it when memory size is constrained, providing flexible optimization of the trade-off between productivity and resource usage.
Solution Approach 2:
The patent changes the bit length parameter dynamically based on the specific decoding situation. By allowing this parameter to vary, the system can optimize the balance between table size (which grows exponentially with bit length) and decoding speed (which improves with longer reference bits), resolving the contradiction between these two opposing requirements.
3Quantity of substance
If the bit length for table reference is decreased, then the table size is reduced, but the number of table references increases causing processing delays
Solution Approach 1:
The patent applies dynamics by adjusting the reference bit length based on the specific code word and decoding context. When memory size is constrained, the system can use shorter reference bits (reducing table size) while compensating for increased reference count through efficient table organization and access patterns, thus minimizing processing delays.
Solution Approach 2:
The patent changes the bit length parameter to be variable rather than fixed, allowing optimization of the trade-off between table size and number of references. By adjusting this parameter based on specific decoding requirements, the system can reduce table memory usage while managing processing delays through intelligent parameter selection.
4Adaptability or versatility
If a decoding process table is designed to handle all code words of m bits or more, then universal decoding is achieved, but the table requires excessive entries increasing memory usage
Solution Approach 1:
The patent applies segmentation by dividing the decoding process into multiple stages or tables rather than using a single large table. By segmenting the decoding functionality, the system can handle different code word patterns in different tables, reducing the number of entries required in each individual table while maintaining universal decoding capability across all code words.
Solution Approach 2:
The patent uses parameter changes by allowing the reference bit length to vary based on the code word being decoded. This enables the system to achieve universal decoding coverage by adjusting parameters for different code patterns rather than designing a single table to handle all possible cases, significantly reducing the total number of table entries required.
Data Source
AI summary
A flag indicating whether a decoding process is completed or continued is disposed in each of entries of a decoding process table. A decoded value and a significant bit length are recorded in the entry of a decoding process completion. Information for identifying the decoding process table which is used in a subsequent process, and a bit length that is clipped from a code word which is used when referring to a subsequent table are recorded in the entry of the decoding process continuation. When the decoding process starts, the information for identifying the table to be used and the bit length that is referred to from the code word when referring to the table are designated together with the code word. The decoding process table reference is repeated as the occasion demands. With the above configuration, there is provided a variable length code decoding device.