Last Significant Coefficient Position Coding for Lower Video Bitrate
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Solution Overview
Problem
Existing video coding methods have high complexity and inefficiency in coding last significant coefficient position information and significant coefficient position information, leading to increased bitrates and computational costs.
Innovation Solution
Coding the last significant coefficient position information prior to coding significant coefficient position information, using methods such as one-dimensional or two-dimensional positioning within a scanning order, or flagging its location within a range, to enable parallel coding and reduce complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If existing video coding methods code last significant coefficient position information and significant coefficient position information in traditional sequence, then coding completeness is maintained, but system complexity and bitrate increase
Solution Approach 1:
The patent segments the coding process into two distinct phases: first coding the last significant coefficient position information, then coding the significant coefficient position information. This segmentation allows each phase to use optimized coding strategies appropriate to its specific requirements, reducing overall complexity while maintaining complete information representation
Solution Approach 2:
The patent performs preliminary coding of the last significant coefficient position information before coding the significant coefficient position information. This preliminary action establishes a foundation that simplifies subsequent coding operations, as the decoder already has context about the last significant coefficient location when processing the significance map
2Loss of information
If traditional coding methods are used for coefficient position information, then coding accuracy is maintained, but bitrate increases
Solution Approach 1:
The patent changes the coding parameters by separating the coding of last significant coefficient position from significant coefficient position. This parameter change allows each to be encoded with appropriate precision requirements, avoiding over-coding and reducing overall bitrate while maintaining accurate position information
Solution Approach 2:
By preliminarily coding the last significant coefficient position, the patent enables the significant coefficient position coding to reference this information, reducing the number of bits needed to represent the complete position information while maintaining full accuracy
3Ease of operation
If significant coefficient position information is coded before last significant coefficient position information, then coding flow is simplified, but complexity and bitrate increase
Solution Approach 1:
The patent inverts the traditional coding sequence by coding the last significant coefficient position information first, rather than coding significant coefficient positions first. This inversion simplifies the overall system complexity because the decoder can use the last significant coefficient position as a reference point, reducing the complexity of processing the significance map
Data Source
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AI summary
An apparatus is disclosed for coding coefficients associated with a block of video data during a video coding process, wherein the apparatus includes a video coder configured to code information that identifies a position of a last nonzero coefficient within the block according to a scanning order associated with the block prior to coding information that identifies positions of other nonzero coefficients within the block, including at least one of the following: coding a one-dimensional position within the block that identifies the position of the last nonzero coefficient; coding a two-dimensional position within the block that identifies the position of the last nonzero coefficient, and coding a flag that indicates whether the last nonzero coefficient is located within a range of positions within the block, and coding the one-dimensional position when the last nonzero coefficient is located within the range, and otherwise coding the two-dimensional position.