Adaptive quantizer with modification of high frequency coefficients
US5892548A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 30, 1996 |
| Grant date | Apr 6, 1999 |
| Priority date | — |
| Expiry date | Dec 30, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/152
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A video signal encoding system, for encoding a video signal to provide an encoded signal, includes a transform coder for encoding the video signal on a block-by-block basis to generate blocks of transform coefficients, wherein the video signal includes a multiplicity of frames, each frame having blocks of pixels. A quantizer employed in the video signal encoding system comprises a quantization parameter deciding block; a quantizer control block for deciding a quantization mode signal which represents an activity of the video signal; and a quantizer which classifies transform coefficients included in each block into high frequency coefficients and low frequency coefficients based on the quantization mode signal, modifies the high frequency coefficients, to thereby provide blocks of modified transform coefficient, and quantizes the blocks of modified transform coefficients by using the quantization parameter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.