Composite-video generation from different-rate constituents
US6606112B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Mar 16, 2000 |
| Grant date | Aug 12, 2003 |
| Priority date | — |
| Expiry date | Mar 16, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N7/152
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Continuous presence designed in accordance with H.261 recommendation allows for several sites to be seen simultaneously on one screen. For instance, the H.261 recommendation specifies that two picture scanning formats (i.e., CIF and QCIF) may be used in a codec. Notably, H.323 end-points could send pictures in QCIF while receiving CIF pictures. An MCU could select four appropriate sites, receive QCIF pictures from those sites, form a composite picture, and distribute the composite picture to the conferencing end-points. It is desired to be able to allow the sites to transmit pictures at different rates according to their preferences. Each site is associated with a queue into which the transmitted QCIF pictures are stored. The transmission rate for those sites are then deduced. A thread then activates to determine if there are QCIF pictures to be placed in the associated queues. Another thread retrieves the QCIF pictures from the queues based on the deduced transmission rate. The retrieved QCIF pictures are then composed into a composite picture which is transmitted such that the composed QCIF is pictures are transmitted at their received transmission rates.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.