End of Block Coding for 2D Coefficients with 1D Transforms
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Solution Overview
Problem
Existing video coding technologies face challenges in efficiently compressing video data due to limited bandwidth and memory resources, particularly in signaling and reconstructing transform coefficients in a way that minimizes redundancy and bit rate.
Innovation Solution
The proposed solution involves deriving a two-dimensional (2D) transform block from one-dimensional (1D) transform coefficients and their corresponding end-of-block (EOB) values, allowing for the omission of trailing zero coefficients from the bitstream without degrading video quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If all transform coefficients are signaled in the video bitstream, then video quality is maintained, but coding overhead and bit rate increase
Solution Approach 1:
The patent extracts and removes trailing zero coefficients from the transform coefficient data before signaling in the bitstream. By identifying the end-of-block (EOB) position where all subsequent coefficients are zero, the invention extracts only the necessary non-zero coefficients and EOB marker, discarding the redundant zero values. This extraction principle directly reduces coding overhead while preserving video quality, as the decoder can reconstruct the original coefficient array by appending zeros after the EOB position.
Solution Approach 2:
The patent changes the representation parameter of transform coefficients by introducing the EOB (end-of-block) marker. Instead of signaling all coefficients individually, the system changes the parameter set to include: (1) the EOB position indicating where trailing zeros begin, and (2) only the non-zero coefficients before the EOB position. This parameter transformation reduces the quantity of data to be transmitted while maintaining the ability to reconstruct the full coefficient array at the decoder.
2Productivity
If trailing zero coefficients are omitted from the bitstream, then coding efficiency improves, but the complexity of deriving the transform block increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and signaling the EOB (end-of-block) position during the encoding phase. The encoder performs the derivation work in advance by scanning coefficients in zig-zag order, identifying where trailing zeros begin, and storing this EOB position information. This preliminary action shifts the computational complexity from the decoding phase to the encoding phase, allowing the decoder to simply append zeros after the EOB position without performing complex derivations, thus improving overall coding efficiency.
Solution Approach 2:
The patent introduces the EOB (end-of-block) marker as an intermediary element that mediates between the compressed coefficient data and the full transform block. The EOB serves as a boundary indicator that tells the decoder where the significant coefficients end and where trailing zeros begin. This intermediary simplifies the derivation process by providing a clear stopping point, eliminating the need for complex analysis at the decoder side while maintaining coding efficiency.
3Quantity of substance
If a two-dimensional transform block is derived from one-dimensional coefficients, then video data compression is achieved, but bandwidth and memory resources are constrained
Solution Approach 1:
The patent applies segmentation by dividing the two-dimensional transform block into a sequential one-dimensional array of coefficients ordered by significance (typically zig-zag order). Instead of transmitting and storing the entire 2D block structure, the invention segments the data into: (1) non-zero coefficients in significance order, and (2) an EOB marker indicating where trailing zeros begin. This segmentation reduces the quantity of data to be transmitted and stored, directly addressing bandwidth and memory constraints while preserving the ability to reconstruct the 2D block structure at the decoder.
Data Source
AI summary
The various implementations described herein include methods and systems for coding video. In one aspect, a method includes receiving a video bitstream comprising a plurality of blocks, including a current block. The method includes parsing, from the video bitstream, a plurality of one-dimensional (1D) transform coefficients corresponding to the current block. The method includes parsing, from the video bitstream, a maximum end-of-block (EOB) value for the plurality of 1D transform coefficients. The method includes deriving a two-dimensional (2D) transform block using the maximum EOB value and the plurality of 1D transform coefficients. The method also includes reconstructing the current block using the derived 2D transform block.