Arithmetic Coding Slice Termination with Stop-Bit Signaling
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Solution Overview
Problem
Conventional arithmetic coding methods, such as those used in the H.264/AVC standard, incur an increase in bits due to the encoding of a terminating syntax element for each macroblock in a slice, which becomes more pronounced with increased slice granularity, leading to inefficiencies in bitstream size.
Innovation Solution
The proposed solution eliminates the encoding of the terminating syntax element for each macroblock, instead using a stop bit to indicate the end of a slice, and adjusts the offset and range values to determine the end of a coded slice, thereby reducing the number of bits in the bitstream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a terminating syntax element is encoded for each macroblock in a slice, then the decoder can determine the end of a coded slice, but the bitstream size increases
Solution Approach 1:
The patent extracts only the essential termination signal (stop bit) from the conventional terminating syntax element, removing unnecessary overhead while preserving the core function of indicating slice termination to the decoder
Solution Approach 2:
Instead of explicitly signaling termination with a syntax element for each macroblock, the invention inverts the approach by using the absence of certain bits combined with a final stop bit to indicate termination, thereby reducing bitstream overhead while maintaining decoding reliability
2Adaptability or versatility
If slice granularity is increased (e.g., 8×8 macroblocks), then finer control is achieved, but bit overhead increases due to more terminating syntax elements
Solution Approach 1:
The patent removes the redundant terminating syntax elements from each macroblock while retaining the essential stop bit mechanism, allowing fine-grained slice control without proportional increase in bit overhead
Solution Approach 2:
The stop bit mechanism serves multiple functions: it indicates slice termination, works across different slice granularities (from 8×8 to larger blocks), and maintains compatibility with the existing CABAC decoding framework, providing universal applicability
Data Source
AI summary
The present invention provides arithmetic encoder and decoder, and methods implemented therein for termination of arithmetic coding. The arithmetic encoder first determines whether a bin value indicates termination of arithmetic encoding. If the bin value is determined not indicating termination of arithmetic encoding, no bit is written in a bitstream indicative of the bin value so determined. If the bin value is determined indicating termination of arithmetic encoding, a stop bit is written in the bitstream. The arithmetic decoder determines whether or not the end of a coded slice has been reached, based on a number of bits in the bitstream. More specifically, the arithmetic decoder makes a determination, based on a number of bits preceding a stop bit located in a last byte in the bitstream.