Variable length coding apparatus and method for motion vector
US5298991A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 24, 1992 |
| Grant date | Mar 29, 1994 |
| Priority date | — |
| Expiry date | Jul 24, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/91
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A ROM containing a variable length coding table for a 2 picture element range is provided. A motion vector within the range of 2 picture elements is provided to the ROM to produce a VLC code corresponding to the motion vector within the range of 2 picture elements. In a calculation circuit, assuming that the value of a motion vector within the range of 4 picture elements is X, a quotient Y and a remainder Z are obtained by the division of X by 2. The quotient Y is supplied to the ROM and the output of the ROM is added the remainder Z at an addition circuit to obtain a VLC code corresponding to the motion vector lying within the range of 4 picture elements. This is equivalent to variable length coding for a 4 picture element range. By transmitting a flag indicating whether the motion vector range is 2 picture elements or 4 picture elements, the motion vector is correctly reproduced from the VLC code. Accordingly motion vectors within the ranges of 2 picture elements and 4 picture elements can be coded using a single ROM table so that the hardware requirements are reduced.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.