Reference pictures for inter-frame differential video coding
US8259802B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 27, 2007 |
| Grant date | Sep 4, 2012 |
| Priority date | — |
| Expiry date | Oct 11, 2029 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/895
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A video encoder using inter-frame differential coding has a store (3) for containing a plurality of reference pictures. For each incoming picture it chooses one (or more) of the stored reference pictures to use. Control means (10) select which locally decoded pictures are to be entered into, and removed from, so that the store always contains at least one relatively older picture that lies within a defined time window and at least one relatively younger picture that is more recent than the time window. When it receives an error message from a receiver, it switches the coder from its normal a state (in which it is allowed to choose any picture as predictor) into a state in which it is permitted to choose only a said relatively older picture for prediction. The beginning of the time window is preferably set according to the estimated (or observed) round trip time between the encoder and decoder such that at least one of the relatively older pictures always predated the error message.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.