Scalable Video Coding with Residual Layers
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Solution Overview
Problem
Existing scalable video codecs face high development and deployment costs due to the coupling of enhancement layer codecs with base layer codecs, requiring different enhancement layer codecs for different base layer standards, and lack efficient scalability options for chroma and sample depth.
Innovation Solution
The use of chroma high-pass residual and sample depth residual layers, allowing for independent encoding and decoding of enhancement layers using the same or different encoders, and enabling scalability by separating the enhancement layer from the base layer codec, with techniques such as wavelet decomposition for residual layer separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If enhancement layer codec is coupled with base layer codec using same macroblocks and motion vectors, then coding efficiency is improved, but development cost and complexity increase due to multiple enhancement layer codecs required for different base layer standards
Solution Approach 1:
The patent segments the enhancement layer from the base layer by introducing separate enhancement layer macroblocks that do not depend on base layer macroblocks. The enhancement layer uses its own motion vectors and coding parameters, allowing independent development and deployment of enhancement layer codecs regardless of base layer standard.
Solution Approach 2:
The patent creates a universal enhancement layer codec that can work with different base layer standards (MPEG-2, H.264, H.265) by using a generic enhancement layer structure that is not tied to any specific base layer format. This single enhancement layer codec can serve multiple base layer standards.
2Manufacturing precision
If chroma and sample depth scalability are supported using traditional methods, then video quality is improved, but coding complexity increases and deployment cost increases
Solution Approach 1:
The patent separates chroma scalability and sample depth scalability into distinct enhancement layer components. The chroma enhancement layer handles chroma quality improvement while the sample depth enhancement layer handles bit depth extension. This segmentation allows each layer to be optimized independently and reduces overall coding complexity.
Solution Approach 2:
The patent introduces sample depth as an additional dimension of scalability alongside traditional spatial and temporal scalability. By adding sample depth enhancement layer, the system achieves higher video quality without requiring complete redesign of the coding framework, thus reducing deployment complexity.
Data Source
AI summary
Techniques and tools are described for scalable video encoding and decoding. In some embodiments, an input frame is downsampled in terms of sample depth and chroma sampling rate, encoded, and output from the encoder as a base layer bitstream. The base layer bitstream is also reconstructed and upsampled to produce a reconstructed bitstream which is subtracted from the original input frame to produce a residual layer. The residual layer is split and encoded as a sample depth residual layer bitstream and a chroma high-pass residual layer bitstream. To recover the encoded input frame, a decoder receives one or more of these bitstreams, decodes them, and combines them to form a reconstructed image. The use of separate codecs is allowed for the base layer and the enhancement layers, without inter-layer dependencies.