Bit Depth Scalable Video Encoding Tone Mapping
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Solution Overview
Problem
Existing bit depth scalable video encoding and decoding methods face challenges in handling different bit depths between enhancement and base layers due to the lack of effective tone mapping and inverse tone mapping operations, leading to compliance issues with standards like MPEG-4 AVC and introducing quantization errors.
Innovation Solution
The proposed solution involves using tone mapping and inverse tone mapping functions that operate at the same bit depth to perform inter-layer residue prediction, converting the problem from the residue domain to the pixel domain, and signaling these functions in the bitstream to maintain a same bit depth representation, thereby minimizing quantization errors and improving coding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If tone mapping and inverse tone mapping operations are applied to handle different bit depths between enhancement and base layers, then bit depth scalability is achieved, but compliance issues with MPEG-4 AVC standards are introduced
Solution Approach 1:
The patent introduces tone mapping and inverse tone mapping as intermediary operations that bridge the base layer and enhancement layer. These operations convert pixel values between different bit depth representations, enabling the enhancement layer to operate at a higher bit depth while maintaining compatibility with the base layer's lower bit depth, thus resolving the contradiction between bit depth scalability and standard compliance
2Productivity
If bit depth scalable coding is implemented to enable 10-bit video with backward compatibility, then coding efficiency is improved, but decoding complexity increases due to the need for tone mapping and inverse tone mapping operations
Solution Approach 1:
The patent applies tone mapping and inverse tone mapping operations during the encoding process to prepare the enhancement layer data for efficient decoding. By pre-converting the pixel values to the appropriate bit depth representation, the decoding process can directly utilize the prepared data without requiring complex real-time conversions, thus improving coding efficiency while managing decoding complexity
3Ease of manufacture
If inter-layer residue prediction is performed using bit shift operations, then implementation simplicity is maintained, but quantization errors are introduced
Solution Approach 1:
The patent changes the parameter used for inter-layer residue prediction from simple bit shift operations to tone mapping and inverse tone mapping operations. This parameter change allows the system to maintain implementation simplicity while significantly improving quantization precision, as the tone mapping operations can accurately convert pixel values between different bit depths without introducing the quantization errors associated with bit shift operations
Data Source
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AI summary
Methods and apparatus are provided for bit depth scalable video encoding and decoding utilizing tone mapping and inverse tone mapping. An apparatus includes an encoder (100) for encoding picture data for at least a portion of a picture by generating an inter-layer residue prediction for the portion using a tone mapping function and an inverse tone mapping function. The tone mapping function and the inverse tone mapping function perform a conversion of the inter-layer residue prediction from a residue domain to a pixel domain for bit depth scalability while maintaining a same bit depth representation.