Locally variable quantization and hybrid variable length coding for image and video compression
US8340448B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 6, 2009 |
| Grant date | Dec 25, 2012 |
| Priority date | — |
| Expiry date | May 22, 2031 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/93
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A coding method, apparatus, and storage media with instructions to carry out a method. The method operates on an ordered series of transform coefficients of a block of image data, and for a fixed quantization method, and includes quantizing and encoding the ordered series to form a coded bitstream. The quantizing and encoding uses one or more variable length code (VLC) mappings. The quantizing includes quantizing to have amplitude-1 at least one coefficient that would be quantized by the fixed quantization method to have zero amplitude, quantizing to have zero amplitude at least one coefficient that would be quantized by the fixed quantization method to have amplitude-1, and using the fixed quantization method to quantize any coefficient that is quantized by the fixed quantization method not to have zero amplitude, amplitude-1, or amplitude-2.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.