Video Stream Random Access Flags for Stable Multi-Layer Decoding
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Solution Overview
Problem
Existing video coding technologies struggle with managing random access points and picture output in coded video streams with multiple layers, particularly in scenarios involving inter-picture prediction and motion compensation, leading to potential decoder crashes and unintended behavior due to unavailable reference pictures.
Innovation Solution
Implement a method for signaling flags in a coded video stream to indicate intra random access point (IRAP) and gradual decoding refresh (GDR) pictures, along with reference picture list construction and unavailable picture generation, ensuring proper decoding and output management in multi-layered video streams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If inter-picture prediction with motion compensation is used to reduce bitrate, then compression ratio is improved, but decoder stability deteriorates due to unavailable reference pictures causing crashes
Solution Approach 1:
The patent introduces preliminary actions by signaling flags (irap_picture_flag and gdr_picture_flag) before decoding to identify IRAP and GDR pictures in advance. This allows the decoder to prepare for random access points and refresh operations beforehand, preventing crashes when reference pictures become unavailable during inter-picture prediction.
Solution Approach 2:
The patent implements beforehand cushioning by managing reference picture lists to exclude unavailable reference pictures before they cause decoding errors. The decoder proactively identifies and removes references to pictures that may not be available, cushioning against potential crashes and ensuring stable operation during random access and refresh scenarios.
2Adaptability or versatility
If multiple layers are used in coded video stream to enable random access, then adaptability is improved, but device complexity increases due to flag signaling and reference picture management
Solution Approach 1:
The patent applies segmentation by dividing the video stream into distinct picture types (IRAP and GDR pictures) with specific flags. This segmentation allows the decoder to handle different picture types with appropriate processing, enabling random access while managing complexity through structured organization of reference picture management.
Solution Approach 2:
The patent uses parameter changes by introducing binary flags (irap_picture_flag and gdr_picture_flag) to indicate picture types. These parameter changes provide a simple, efficient mechanism for signaling random access points and refresh operations without requiring complex metadata, thus enabling adaptability while minimizing device complexity.
3Adaptability or versatility
If reference pictures are resampled to different resolutions, then adaptability is improved, but manufacturing precision deteriorates due to potential loss of picture quality
Solution Approach 1:
The patent applies local quality by allowing different reference pictures to have different resolutions based on their specific needs. Instead of uniformly resampling all pictures, the system selectively applies resolution changes only where necessary, preserving original quality where possible while providing adaptability where required.
Solution Approach 2:
The patent implements preliminary action by signaling resolution change information in advance before decoding and reference picture usage. This allows the decoder to prepare appropriate resampling operations beforehand, ensuring that quality is maintained through controlled, pre-planned resolution adjustments rather than ad-hoc changes that could degrade picture quality.
Data Source
AI summary
Systems and methods for decoding a coded video stream are provided. A method includes receiving a coded video stream that includes an access unit, including a picture; signaling a first flag that indicates whether the access unit includes either or neither one from among an intra random access point (IRAP) picture and a gradual decoding refresh (GDR) picture; signaling a second flag that indicates whether the picture is the IRAP picture; and decoding the picture, as a current picture, based on the signaling of the first flag and the second flag, wherein a value of the first flag and a value of the second flag are aligned.