Canvas Size Scalability for HDR Video Across 4K and 8K Layers
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Solution Overview
Problem
Current video coding standards struggle to efficiently support scalable distribution of high dynamic range (HDR) content across different resolutions, particularly 4K and 8K, while maintaining compatibility with existing playback devices and minimizing loss of coding efficiency.
Innovation Solution
Implement canvas size scalability by enhancing HEVC tile concepts with layer-adaptive slice addressing, cross-boundary prediction and entropy coding, and post-filtering to enable independent decoding of regions of interest, using SEI messaging for in-loop filtering, and combining reference picture resampling and selection to support single-loop decoding across varying resolutions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If video content is distributed in multiple resolutions (4K and 8K) to support future playback devices, then forward compatibility and adaptability are improved, but device complexity and storage requirements increase
Solution Approach 1:
The video content is segmented into different resolution layers (4K and 8K) within a scalable video coding structure. Each layer can be independently decoded and played back, allowing distribution of multiple resolutions without requiring separate complete video files for each resolution.
Solution Approach 2:
The patent implements nested resolution layers where lower resolution content (4K) is embedded within the higher resolution content (8K) structure. This allows a single bitstream to contain multiple resolution versions, with enhancement layers providing the difference between base and enhanced resolutions.
2Reliability
If separate versions of HDR content are derived and distributed for existing playback devices, then compatibility with legacy devices is improved, but loss of information and distribution overhead increase
Solution Approach 1:
The scalable video coding structure dynamically adapts to different playback device capabilities. The decoder can selectively process only the necessary layers based on device resolution requirements, avoiding the need to distribute and process unnecessary high-resolution data for legacy devices.
Solution Approach 2:
The video content is pre-processed into a scalable structure with embedded resolution layers and region of interest markers during encoding. This preliminary organization allows legacy devices to efficiently extract and decode only the appropriate resolution content without requiring post-processing or re-encoding.
3Adaptability or versatility
If canvas size scalability with independent region decoding is implemented, then decoding flexibility and adaptability are improved, but device complexity and processing requirements increase
Solution Approach 1:
The patent extracts and marks regions of interest within the video content with specific metadata and scaling parameters. These marked regions can be independently decoded and scaled to different resolutions, allowing players to extract only the necessary portions for the target display without decoding the entire high-resolution content.
Solution Approach 2:
The scalable video structure creates copied representations of the same visual content at different resolutions and regions. Instead of requiring complex real-time processing, the decoder selects from pre-encoded copies that match the target display characteristics.
Data Source
AI summary
Methods and systems for canvas size scalability across the same or different bitstream layers of a video coded bitstream are described. Offset parameters for a conformance window, a reference region of interest (ROI) in a reference layer, and a current ROI in a current layer are received. The width and height of a current ROI and a reference ROI are computed based on the offset parameters and they are used to generate a width and height scaling factor to be used by a reference picture resampling unit to generate an output picture based on the current ROI and the reference ROI.