DRAP Sample Entry Signaling for Cross-RAP Video Decoding
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Solution Overview
Problem
Existing video coding standards, such as VVC and HEVC, lack effective signaling mechanisms for cross Random Access Point (RAP) referencing, particularly for dependent random access points (DRAP) and Cross RAP Referencing (CRR), leading to potential decoding errors and inefficiencies in video decoding processes.
Innovation Solution
Implementing a signaling mechanism through Supplemental Enhancement Information (SEI) messages to indicate whether inter predicted pictures following a DRAP/CRR picture in decoding order but preceding it in output order are allowed to reference earlier pictures, and defining sample groups in ISOBMFF media files to accurately describe DRAP and CRR pictures, ensuring correct decoding and presentation order.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing video coding standards (VVC, HEVC) are used without DRAP/CRR signaling mechanisms, then device complexity is reduced, but decoding reliability deteriorates due to potential decoding errors
Solution Approach 1:
The patent introduces SEI messages as an intermediary mechanism to carry DRAP/CRR signaling information between encoder and decoder. These messages act as a mediator that conveys reference picture list information without requiring changes to the core video coding standards, thus improving decoding reliability while minimizing complexity increases to the signaling infrastructure
Solution Approach 2:
The signaling mechanism is segmented into separate SEI messages that can be independently processed and transmitted. This segmentation allows the DRAP/CRR information to be conveyed in discrete units, reducing the complexity burden on the overall system while ensuring reliable delivery of critical decoding information
2Measurement precision
If DRAP/CRR signaling is implemented through SEI messages, then decoding accuracy is improved, but information processing overhead increases
Solution Approach 1:
The SEI messages are designed to be self-contained with all necessary information for the decoder to correctly interpret and apply DRAP/CRR signaling. Each message includes complete reference picture list information and syntax elements that enable the decoder to autonomously process the signaling without requiring additional external information or complex cross-referencing, thus reducing information processing overhead while maintaining high decoding accuracy
3Reliability
If sample groups are defined in ISOBMFF media files to describe DRAP/CRR pictures, then video presentation correctness is improved, but file structure complexity increases
Solution Approach 1:
The patent embeds DRAP/CRR sample group information within the existing ISOBMFF media file structure using nested boxes and syntax elements. The sample group information is nested within track boxes and sample entries, allowing the complex DRAP/CRR metadata to be organized in a hierarchical manner that mirrors the existing file structure, thus improving video presentation correctness while minimizing the perceived file structure complexity
Data Source
AI summary
A mechanism for processing video data is disclosed. A dependent random access point (DRAP) sample entry is signaled in a DRAP sample group. The DRAP sample entry describes one or more DRAP samples. A conversion is performed between a visual media data and a visual media data file based on the DRAP sample entry.