Picture Header NAL Placement for Identifier-Free Video Coding
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Solution Overview
Problem
Existing video coding technologies face inefficiencies in determining the starting point of a picture within a multi-layer bitstream, leading to unnecessary bit usage and reduced coding efficiency.
Innovation Solution
Ensuring that a picture header network abstraction layer unit precedes the first video coding layer unit in a picture unit, eliminating the need for a picture header identifier, thereby reducing bits in the bitstream and improving coding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a picture header identifier (ID) is signaled in the picture header to identify picture associations, then picture identification accuracy is improved, but bitstream size increases and coding efficiency deteriorates
Solution Approach 1:
The patent extracts and removes the picture header identifier (ID) signaling from the bitstream. By eliminating this redundant identification field, the patent achieves both goals: picture associations are still accurately determined through the structural positioning (PH NAL unit preceding VCL NAL units), while bitstream size is reduced. This extraction principle directly resolves the contradiction by removing unnecessary data while preserving functional accuracy.
Solution Approach 2:
The patent enables the decoder to self-determine picture associations through the inherent structural arrangement of NAL units rather than relying on explicit identifier signaling. The decoder can infer picture boundaries and associations by detecting the PH NAL unit position relative to VCL NAL units, allowing the system to serve itself without additional identification bits, thus reducing bitstream size while maintaining identification accuracy.
2Reliability
If picture header identifier signaling is implemented, then picture association determination is improved, but coding efficiency deteriorates due to increased bit usage
Solution Approach 1:
The patent removes the picture header identifier signaling mechanism from the code structure. By extracting this redundant identification element, the patent maintains reliable picture association determination through the structural relationship between PH NAL units and VCL NAL units, while simultaneously improving coding efficiency by eliminating the bits required for identifier signaling.
Solution Approach 2:
The patent introduces the structural positioning of PH NAL units as an intermediary mechanism that mediates between the need for reliable picture association determination and the goal of coding efficiency. Instead of using explicit identifier bits, the structural arrangement itself serves as the mediator that conveys association information without additional bit overhead, thus resolving the contradiction between reliability and productivity.
3Productivity
If redundant bits are eliminated from the bitstream, then coding efficiency is improved, but the complexity of picture header structure increases
Solution Approach 1:
The patent leverages the existing structural pattern of NAL unit arrangement as a template or model for picture association determination. By copying the successful structural positioning approach used in other video coding contexts and applying it to picture header identification, the patent achieves coding efficiency improvement without significantly increasing complexity, as the decoder already possesses the capability to parse and interpret such structural relationships.
Data Source
AI summary
A method of decoding is provided. The method includes receiving a video bitstream including a picture unit (PU), where the PU includes a picture header (PH) network abstraction layer (NAL) unit preceding a first video coding layer (VCL) NAL unit, and decoding a coded picture from the PU to obtain a decoded picture.