Inverse quantizer for use in MPEG-2 decoder
US5712686A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 27, 1996 |
| Grant date | Jan 27, 1998 |
| Priority date | — |
| Expiry date | Dec 27, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/124
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An inverse quantizer, for use in an MPEG-2 video signal decoder, provides a 23-bit inverse quantized transform coefficient F in response to 13-bit (2QF+K), according to F=(2QF+K).times.(W.times.quantizer.sub.-- scale )!/32 wherein QF is a quantized transform coefficient, W is an element of a predetermined weight matrix, and the quantizer.sub.-- scale is an integer ranging from 1 to 112 as given in MPEG-2 scheme. The inverse quantizer comprises a quantizer.sub.-- scale providing block for providing a (7-L)-bit modified quantizer.sub.-- scale and a selection signal based on the quantizer.sub.-- scale; a first multiplier for multiplying the modified quantizer.sub.-- scale with W, to provide a (15-L)-bit quantization step size; a second multiplier for multiplying (2QF+K) with the quantization step size, to provide a (28-L) bit output; a bit appending block for appending L zero bits to the output of the second multiplier, to provide a set of (L+1) 28-bit values; a multiplexor for selecting one of the (L+) 28-bit values in response to the selection signal; and a divider for dividing the selected 28-bit value by "2.sup.5 ", to thereby provide 23-bit F.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.