Bi-level Video Compression for Low Bandwidth Transmission
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Solution Overview
Problem
Existing video broadcast and communication technologies require high bandwidths for smooth video transmission, leading to unsatisfactory results on low-bandwidth devices like handheld PCs and mobile phones, where images appear as color blocks and motion is discontinuous due to the limitations of MPEG, MPEG2, MPEG4, and H.263 compression methods.
Innovation Solution
A system and process for broadcasting and communicating bi-level or sketch video at extremely low bandwidths, converting color or gray-scale video to bi-level video, which presents outlines of objects, and using adaptive context-based arithmetic coding and rate control to ensure clear images and smooth motion on low-bandwidth devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If MPEG, MPEG2, MPEG4, or H.263 compression methods are used, then video can be transmitted over broadcast channels, but the bandwidth requirement increases to 20-30 Kbps or higher, which is not suitable for low-bandwidth devices
Solution Approach 1:
The patent fundamentally changes the video representation parameters by converting color video (millions of colors) to bi-level video (only black and white). This parameter transformation reduces the color information to binary values, enabling compression to extremely low bitrates (9.6 Kbps or lower) while maintaining recognizable video content and smooth motion on low-bandwidth devices
Solution Approach 2:
The patent extracts only the essential outline information from the video by applying edge detection algorithms to identify and preserve only the boundary pixels of objects. This extraction process removes redundant color and internal detail information, keeping only the critical structural elements needed for recognizable video representation at very low bandwidths
2Quantity of substance
If DCT-based compression is used at very low bandwidth, then some compression is achieved, but the images appear as color blocks and motion becomes discontinuous
Solution Approach 1:
The patent changes the fundamental parameter of video representation from continuous color values to binary bi-level values. This transformation eliminates the blocky artifacts inherent in DCT-based methods because bi-level encoding preserves outline continuity without relying on block-based frequency transformation, resulting in smooth motion and clear images even at 9.6 Kbps or lower bandwidths
Solution Approach 2:
Instead of compressing by transforming to frequency domain and quantizing (the conventional DCT approach), the patent inverts the approach by first converting to bi-level space and then applying adaptive arithmetic coding. This inversion allows the system to achieve better compression efficiency and image quality at very low bandwidths by encoding the binary outline information more effectively
Data Source
AI summary
A system and process for broadcast and communication with bi-level or sketch video at extremely low bandwidths is described. Essentially, bi-level and sketch video presents the outlines of the objects in a scene being depicted. Bi-level and sketch video provides a clearer shape, smoother motion, shorter initial latency and cheaper computational cost than do conventional DCT-based video compression methods. This is accomplished by converting each color or gray-scale image frame to bi-level or sketch image frame using adaptive thresholding method, compressing bi-level or sketch image frames into bi-level or sketch video using adaptive context-based arithmetic coding method. Bi-level or sketch video is particularly suitable to such small devices as Pocket PCs and mobile phones that possess small display screen, low bandwidth connection, and light computational power.