Dynamically scaled file encoding
US7567722B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 22, 2005 |
| Grant date | Jul 28, 2009 |
| Priority date | — |
| Expiry date | Aug 2, 2027 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/60
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A dynamically scaled file encoding method and apparatus are disclosed. A file encoding system using JPEG encoding can be configured to produce relatively constant compressed file sizes irrespective of the initial file size and file contents. The system retrieves an initial file or image that is to be compressed and determines a target bit rate corresponding to the compressed file. The target bit rate is used to determine an initial scaling factor. The initial file is encoded using a JPEG encoder having coefficients scaled by the initial scaling factor. The resultant bit rate can be adjusted in a second loop if greater than the desired bit rate. To adjust the bit rate, a recomputed scaling factor is determined from the resultant bit rate. The initial file is then encoded with coefficients scaled by the recomputed scaling factor to achieve a bit rate that is within the target bit rate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.