Low cost video compression using fast, modified Z-coding of wavelet pyramids
US8116377B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 6, 2009 |
| Grant date | Feb 14, 2012 |
| Priority date | — |
| Expiry date | May 6, 2030 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/13
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An entropy efficient video coder for wavelet pyramids approaches the entropy-limited coding rate of video wavelet pyramids, is fast in both hardware and software implementations, and has low complexity (no multiplies) for use in ASICs. It uses a modified Z-coder to code the zero/non-zero significance function and Huffman coding for the non-zero coefficients themselves. The encoding unit includes a significance function generator that receives coefficients and outputs a single significance bit. A zero coefficient eliminator receives coefficients in parallel with the significance function generator and outputs coefficients if non-zero. Output from the significance function generator is coded using the modified Z-coder. Output from the zero coefficient eliminator is coded using Huffman coding. Both outputs are combined to form the resulting compressed stream. The modified Z-coder is similar to a standard Z-coder but uses a different technique for the LPS (least probable symbol) case during encoding and decoding that results in a Z-coder that functions appropriately.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.