Intra Block Copy Prediction Mode Flag in Video Coding
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Solution Overview
Problem
Existing video coding technologies face inefficiencies in decoding data blocks coded in intra block copy prediction mode, particularly in maintaining consistency between syntax and semantics, and in reducing bit rate costs.
Innovation Solution
A method for video coding and decoding that includes carrying specific indication information in bitstream data to identify blocks coded in intra block copy prediction mode, using flags to specify prediction modes, and optimizing coding performance by determining the lowest rate distortion cost for prediction modes, while ensuring consistent entropy coding contexts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If intra block copy prediction mode is used for coding current block, then coding flexibility and applicability to various slice types is improved, but decoding efficiency and syntax-semantics consistency deteriorates due to lack of explicit indication information
Solution Approach 1:
The patent segments the prediction mode indication by introducing a dedicated flag (intra_block_copy_prediction_mode_flag) that specifically identifies intra block copy mode, separating it from general intra/inter prediction mode classification. This segmentation allows the decoder to quickly identify and handle intra block copy blocks without ambiguity, resolving the syntax-semantics consistency issue while maintaining coding flexibility.
Solution Approach 2:
The patent introduces an intermediary flag (intra_block_copy_prediction_mode_flag) that acts as a mediator between the encoder's choice of intra block copy mode and the decoder's interpretation. This flag serves as explicit communication that resolves the ambiguity in syntax-semantics mapping, improving decoding efficiency without limiting the encoder's flexibility in selecting prediction modes.
2Quantity of substance
If intra block copy prediction mode is used without explicit indication, then bit rate is reduced, but syntax-semantics consistency and decoding accuracy worsen
Solution Approach 1:
The patent applies partial action by introducing a minimal overhead flag (intra_block_copy_prediction_mode_flag) that provides just enough explicit indication to resolve syntax-semantics consistency issues. This flag adds only one bit of information per block, which is excessive enough to ensure accurate decoding but minimal enough to maintain efficient bit rate, striking a balance between the two competing requirements.
3Adaptability or versatility
If slice type is modified to P slice when using intra block copy on I slice, then intra block copy functionality is enabled, but slice type consistency and coding structure clarity deteriorates
Solution Approach 1:
The patent segments the prediction mode indication from the slice type modification by introducing a dedicated flag (intra_block_copy_prediction_mode_flag) that operates independently of slice type. This allows intra block copy functionality to be enabled on I slices without modifying the slice type, maintaining slice type consistency and structural clarity while enabling the desired functionality through the flag mechanism.
Data Source
AI summary
The disclosure provides a video coding method and a video coding apparatus and a video decoding method and a video decoding apparatus. The video coding method includes: when determining that a current block is coded in intra block copy prediction mode, carrying first indication information and second indication information in bitstream data corresponding to the current block by a video coder, wherein the first indication information specifies that a prediction mode of the current block is intra prediction, the second indication information specifies that the current block is coded in intra block copy prediction mode; and sending the bitstream data with the first indication information and the second indication information by the video coder. In this way, efficiency of a video decoder to know that a data block is coded in intra block copy prediction mode may be improved by using the video coding method, and consistence between syntax and semantics when prediction coding/decoding the data block in intra block copy prediction mode may be ensured.