Rate control for an MPEG transcoder without a priori knowledge of picture type
US6570922B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 24, 1998 |
| Grant date | May 27, 2003 |
| Priority date | — |
| Expiry date | Nov 24, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/61
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A rate control system suitable for use with a digital video transcoder, such as one conforming to the MPEG standard. The proposed rate control system starts coding with any reasonable set of assumed Group of Pictures (GOP) parameters, thereby avoiding a processing delay of about one GOP which would otherwise be incurred to extract the complete GOP structure information from a pre-compressed bit stream. In addition, the system avoids the need to store the data corresponding to the GOP, thereby reducing the memory required for transcoding. Encoding of a first picture in a sequence or GOP begins without a priori knowledge of the picture type of subsequent pictures. A reasonable set of GOP parameters is assumed to determine an encoding bit budget. The bit budget is gradually corrected as successive pictures are coded according to their picture types. Changes in the GOP structure of pre-compressed bitstreams can be addressed, for example, when switching channels, inserting commercials, and the like. Target rates with incorrect starting GOP parameters will converge within a few GOPs.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.