Scalable Video Coding ROI Mapping via Slice Groups
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Solution Overview
Problem
Current scalable video coding (SVC) methods do not effectively support the encoding and decoding of multiple regions of interest (ROIs) with scalability, particularly in cases where overlapped regions exist, leading to inefficiencies in bitstream transmission and decoding.
Innovation Solution
A method involving a multiple ROI setting apparatus that allocates ROI identification numbers and slice group identification numbers, generates messages with associated information, and selects bitstreams based on ROI and scalability criteria, allowing for independent decoding of ROIs using flexible macroblock ordering (FMO) and supplemental enhancement information (SEI) messages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple ROIs are encoded in SVC with scalability, then video quality for different devices is improved, but bitstream complexity and decoding difficulty increase
Solution Approach 1:
The video frame is segmented into multiple slice groups, each corresponding to a specific ROI. This segmentation allows independent encoding and decoding of different ROIs with different scalability parameters, enabling adaptive video quality for different devices while maintaining manageable bitstream structure through clear regional division
Solution Approach 2:
Different ROI regions are assigned different quality levels and scalability parameters based on their importance. High-priority ROIs receive higher quality encoding and multiple scalability layers, while low-priority regions use baseline encoding, achieving overall video quality adaptability without uniformly increasing bitstream complexity across the entire frame
2Ease of operation
If overlapped ROI regions are handled separately, then decoding flexibility is improved, but encoding overhead and processing time increase
Solution Approach 1:
Overlapped ROI regions are merged into a single slice group rather than creating separate slice groups for each ROI. This merging approach maintains decoding flexibility by allowing selective decoding of parent ROIs while reducing encoding overhead and processing time by avoiding redundant handling of overlapping regions
Solution Approach 2:
A mapping structure is introduced as an intermediary between ROIs and slice groups. This mapping efficiently represents the relationship between multiple ROIs and their corresponding slice groups, enabling flexible decoding through the mapping table without requiring complex real-time processing during encoding
3Adaptability or versatility
If ROI-specific slice groups are created, then independent ROI decoding is improved, but bitstream structure complexity increases
Solution Approach 1:
The bitstream is segmented into slice groups with clear boundaries, where each slice group corresponds to specific ROI(s). This segmentation enables independent decoding of ROIs by allowing the decoder to process only the relevant slice groups, while the overall bitstream structure remains organized and manageable through this systematic division
Solution Approach 2:
Slice groups serve multiple functions: they define ROI boundaries, carry scalability information, and enable selective decoding. This multi-functionality reduces bitstream structure complexity by using a single organizational unit (slice group) to accomplish multiple tasks rather than requiring separate structures for each function
Data Source
AI summary
A multiple ROI (region of interest) setting method and apparatus in scalable video coding and an ROI reconstructing method and apparatus are provided. The multiple ROI setting apparatus includes: an ROI setting unit which sets at least one or more ROIs and allocates ROI identification numbers to the each of ROIs; a mapping unit which allocates at least one or more slice group identification numbers to the at least one or more ROI identification numbers; and a message generating unit which generates a message including ROI-associated information, slice-group-associated information, mapping information on mapping of the ROI identification number to the at least one or more slice group identification numbers, and scalability information.