Mode Signaling for 3D Video Coding Reducing Bitstream Redundancy
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Solution Overview
Problem
Current 3D and multi-view video coding technologies face inefficiencies in mode signaling, particularly in reducing inter-view redundancy and optimizing coding unit syntax for PCM, SDC, and DBBP modes, leading to redundant signaling and suboptimal coding efficiency.
Innovation Solution
The method involves signaling a first mode flag for either PCM, SDC, or DBBP modes, where if enabled, the corresponding mode is applied, and signaling of remaining modes is skipped, with specific conditions in coding unit and extension syntax to determine flag inclusion, ensuring efficient mode signaling and reduced redundancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple mode flags (PCM, SDC, DBBP) are signaled independently in the coding unit syntax, then the decoder can accurately identify which modes are enabled, but the bitstream becomes redundant and coding efficiency decreases
Solution Approach 1:
The patent combines multiple mode flags (PCM_flag, SDC_flag, DBBP_flag) into a single unified mode signaling mechanism. Instead of independently signaling each mode flag, the encoder selects one primary mode from the group and signals it using a single flag, while the decoder infers the status of other modes based on the primary mode selection and enable flags. This merging approach eliminates redundant signaling while maintaining accurate mode identification.
Solution Approach 2:
The patent creates a universal mode flag that serves multiple functions: it identifies the primary coding mode (PCM, SDC, or DBBP), triggers conditional signaling of other mode enable flags, and enables the decoder to infer the status of non-selected modes. This single flag structure replaces what would otherwise require multiple independent flags, achieving multi-functionality with a unified signaling mechanism.
2Adaptability or versatility
If all mode enable flags (PCM_enabled_flag, SDC_enabled_flag, DBBP_enabled_flag) are always signaled, then the decoder has complete information about available modes, but the bitstream size increases and signaling overhead grows
Solution Approach 1:
The patent uses a primary mode selection flag as a preliminary indicator that determines whether other mode enable flags should be signaled. The decoder first checks the primary mode flag to understand which mode is active, then conditionally processes the enable flags based on this preliminary information. This preliminary action allows the system to signal only the necessary enable flags, reducing bitstream size while maintaining complete mode availability information where needed.
Solution Approach 2:
The patent implements dynamic signaling where the presence and number of mode enable flags in the bitstream varies based on the primary mode selection. When a specific mode is selected as primary, only its corresponding enable flag is signaled; when other modes are selected, different combinations of enable flags are signaled. This dynamic adaptation of the signaling structure optimizes bitstream size while providing necessary mode information.
3Ease of manufacture
If the coding unit syntax includes extensive mode-related flags and conditions, then the encoder can precisely control which modes are applied, but the syntax complexity increases and processing overhead grows
Solution Approach 1:
The patent extracts the essential mode selection function from the complex syntax structure and isolates it into a primary mode flag. This extracted primary flag serves as the main control mechanism, while the detailed mode control is achieved through conditional logic that activates only when necessary. By separating the core selection function from the detailed control mechanisms, the syntax becomes simpler while maintaining precise mode control capability.
Solution Approach 2:
The patent implements a self-service signaling mechanism where the primary mode flag automatically determines which other flags need to be signaled. The syntax structure itself provides the control logic: when the primary mode flag indicates a specific mode, the corresponding enable flag is automatically included in the bitstream, and the decoder automatically infers the status of other modes. This self-service approach reduces the need for external control mechanisms and simplifies the overall syntax while maintaining precise control.
Data Source
AI summary
A method and apparatus for signaling one or more coding modes selected from a mode group for multi-view or three-dimensional (3D) video coding are disclosed. The mode group comprises a pulse code modulation (PCM) mode, a segment-wise depth coding (SDC) mode and a depth-based block partitioning (DBBP) mode. According to the present invention, a first mode is determined regarding whether it is enabled, where the first mode corresponds to one of at least two mode members selected from the PCM mode, the SDC mode and the DBBP mode. If the first mode is enabled, a first mode flag corresponding to the first mode is signaled to indicate whether the first mode is asserted. If the first mode is asserted, the current depth or texture block is coded using the first mode and signaling any remaining mode member of at least two mode members is skipped.