Conditional Secondary Transform Signaling in Image Encoding
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Solution Overview
Problem
The existing encoding methods in versatile video coding (VVC) result in redundancy and reduced encoding efficiency due to unnecessary signaling of secondary transform control information, particularly when the transform skip flags for chroma components are true.
Innovation Solution
An image processing device and method that omits encoding or decoding of secondary transform control information based on the status of transform skip flags for valid components, ensuring the information is only signaled when all flags are false, thereby reducing redundancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If secondary transform control information is always signaled regardless of transform skip flag status, then the decoding side can correctly reconstruct the transform process, but encoding redundancy increases and encoding efficiency decreases
Solution Approach 1:
The patent applies dynamics by making the signaling of secondary transform control information conditional rather than static. The encoder dynamically adjusts whether to signal the LFNST identifier based on the transform skip flag status, allowing the system to adapt between two operational modes (signaling and non-signaling) to optimize encoding efficiency while ensuring decoding correctness when needed
Solution Approach 2:
The patent changes the parameter of information signaling based on the state of the transform skip flag. When the flag indicates transform skipping, the secondary transform control information parameter is set to a predetermined value and signaling is omitted. This parameter change approach allows the system to maintain reliability when transforms are performed while improving encoding efficiency when transforms are skipped
2Productivity
If secondary transform control information is omitted when transform skip flags are true, then encoding efficiency is improved and redundancy is reduced, but the decoding side needs reliable methods to estimate the correct values
Solution Approach 1:
The patent applies preliminary action by establishing a predetermined value for the secondary transform control information that the decoder can use when signaling is omitted. This pre-defined value (typically indicating skip of secondary transform) is set in advance and agreed upon between encoder and decoder, allowing the decoder to correctly estimate the value without complex analysis when the transform skip flag is true
Solution Approach 2:
The decoder performs self-service by autonomously estimating the secondary transform control information value based on the transform skip flag status and the predetermined value agreement. When the flag indicates skipping, the decoder independently determines the control information value without requiring additional signaling or complex inference, simplifying the decoding process
Data Source
AI summary
The present disclosure relates to an image processing device and method for enabling suppression of reduction in encoding efficiency. Encoding of secondary transform control information that is control information related to secondary transform is omitted in a case where a transform skip flag of at least one component among valid components in image encoding is true, and the secondary transform control information is encoded in a case where the transform skip flags of all the components among the valid components in image encoding are false. The present disclosure can be applied to, for example, an image processing device, an image encoding device, an image decoding device, a transmission device, a reception device, a transmission/reception device, an information processing device, an imaging device, a reproduction device, an electronic device, an image processing method, an information processing method, or the like.