Adaptive Transform Block Size Notification in Video Coding
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Solution Overview
Problem
Existing video coding methods face challenges in flexibly using various transform block sizes to enhance image quality and efficiently coding video sequences at high compression ratios, with implicit modes limiting adaptability and explicit modes requiring excessive bits for notification.
Innovation Solution
A video coding method that determines and notifies transform block sizes on a block-by-block basis using either implicit or explicit modes, allowing flexible switching between modes for each sequence, picture, or slice, thereby enabling adaptive block transform and improving coding efficiency and quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If explicit mode is used to notify transform block size at macroblock level, then adaptability of transform block sizes is improved, but number of bits required for notification increases
Solution Approach 1:
The patent applies local quality by allowing different notification modes (implicit or explicit) to be selected for different macroblocks based on local characteristics. The encoder determines whether to use implicit mode (using motion compensation block size) or explicit mode (transmitting transform block size flag) on a per-macroblock basis, optimizing the balance between adaptability and bit usage for each local region.
Solution Approach 2:
The patent implements dynamics by enabling flexible switching between implicit and explicit notification modes. The system dynamically selects the appropriate mode based on picture characteristics, motion complexity, and coding conditions, rather than using a fixed notification approach throughout the entire video sequence.
2Productivity
If adaptive block transform is disabled for high compression ratio coding, then coding efficiency is improved, but video quality deteriorates
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the transform block size parameter based on picture characteristics, motion vectors, and coding conditions. The encoder can select from multiple transform block sizes (e.g., 4×4, 8×8, 16×16) and switch between implicit and explicit notification modes to optimize the balance between compression ratio and reconstruction quality for different picture types.
Data Source
AI summary
The present invention provides a video coding method and a video decoding method which allow enhancement of coding efficiency and improvement in video quality. A video coding apparatus includes: a mode determination unit which determines a notification method for notifying a transform block size to be used in orthogonal transform of a current block to be either the implicit mode or the explicit mode, and outputs the ABT mode indicating the determined notification method; an orthogonal transformation unit which transforms the difference values between the input image and predicted image into frequency coefficients based on the transform block size determined in accordance with the determined notification method; a quantization unit which quantizes the frequency coefficients and output the quantized values; and a variable length coding unit which performs variable length coding on the quantized values, the ABT mode, and the like, so as to output a coded stream.