Video Compression Device Predictive Mode Selection Circuit
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Solution Overview
Problem
Conventional video compression techniques face challenges in increasing operation frequency and throughput due to large pulse circuit delays when providing multiple predictive modes for DPCM compression, which are necessary for high compression rates, especially when compressing one pixel per cycle.
Innovation Solution
A video compression device architecture that includes an input original image buffer, a line memory, a predictive pixel generation unit, a predictive mode determination unit, a DPCM unit, a quantization unit, an inverse quantization unit, and an inverse DPCM unit, which generates predictive pixel values using local decode pixels and original image pixels as references, allowing for efficient predictive mode determination and compression without relying on local decode pixel generation delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If many predictive modes are provided for DPCM compression, then compression rate is improved, but operation frequency decreases due to large pulse circuit delays
Solution Approach 1:
The patent divides the image data processing into blocks of multiple pixels (e.g., 4x4, 8x8 blocks) rather than processing one pixel at a time. This segmentation allows the system to perform predictive mode determination on multiple pixels simultaneously, increasing throughput while maintaining the use of multiple predictive modes for high compression rates.
Solution Approach 2:
The patent performs predictive mode determination in advance for multiple pixels within a block before actual compression. By pre-calculating which predictive mode (e.g., intra prediction modes) is best for each pixel or group of pixels, the system avoids time-critical path delays during the main compression operation, thereby increasing operation frequency while maintaining compression efficiency.
2Productivity
If local decode pixels are generated within one cycle for predictive mode determination, then throughput is improved, but circuit complexity increases due to large pulse circuit delays
Solution Approach 1:
The patent combines multiple functions into unified processing units. The predictive pixel generation unit integrates multiple predictive mode calculations (e.g., planar prediction, angular prediction) into a single hardware block that operates on multiple pixels simultaneously. This merging reduces the number of separate circuits needed while maintaining high throughput.
Solution Approach 2:
The patent transitions from one-dimensional sequential pixel processing to two-dimensional block processing. By organizing pixels into blocks and performing operations across the block dimension simultaneously, the system achieves higher throughput without proportionally increasing circuit complexity, as the same circuit resources are reused across multiple pixels within each block.
Data Source
AI summary
With a video compression device configured to compress one pixel per cycle, a predictive pixel generation unit generates predictive pixel values of a plurality of predictive modes defined assuming local decode pixels read from predetermined positions of a line memory as upper reference pixels and an input original image pixel positioned on the left side of a pixel to be compressed as a left reference pixel for the pixel to be compressed. A predictive mode determination unit calculates a predictive error in a unit based on differential values between the pixel value to be compressed and the predictive pixel value, and selects a minimum predictive mode. A DPCM unit generates a minimum differential value between the minimum predictive pixel value and the pixel to be compressed assuming local decode pixels as upper reference pixels and a local decode pixel value one cycle before as a left reference pixel.