Method of selecting a requantization step size and controlling a bit-rate
US6208688A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Nov 30, 1998 |
| Grant date | Mar 27, 2001 |
| Priority date | — |
| Expiry date | Nov 30, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/176
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method selects a requantization step size which abruptly changes a bit-rate in a piecewise linearly decreasing model and controls the bit-rate. The method includes: deciding a minimum value of the requantization step size Q2, satisfying 2.multidot.Q1+nint(p.multidot.Q2/q)<2.multidot.Q2 for a quantization step size Q1 of a coded image block of a video image, as requantization step size information; determining a minimum value of a requantization step size Q2, satisfying 4.multidot.Q1+nint(p.multidot.Q2/q)<2.multidot.Q2 for the quantization step size Q1 of the coded image block, as the requantization step size information; taking a minimum value of a requantization step size Q2, satisfying 3.multidot.Q1<2.multidot.Q2 for the quantization step size Q1 of the coded image block, as the requantization step size information; and choosing a minimum value of a requantization step size Q2, satisfying 5.multidot.Q1<2.multidot.Q2 for the quantization step size Q1 of the coded image block, as the requantization step size information, wherein nint(.multidot.) is a nearest integer operator and p and q represent positive integers, respectively.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.