Audio-to-video synchronization system and method for packet-based network video conferencing
US7664057B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 13, 2004 |
| Grant date | Feb 16, 2010 |
| Priority date | — |
| Expiry date | Sep 18, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04Q2213/13389
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Synchronizing audio and video streams in packet-based networks requires synchronization of packet timestamps. The present invention provides such synchronization without resort to a network time standard. In one embodiment of the present invention, pairs of timestamp synchronized signals, such as audio and video signals, not having a common timestamp clock are mixed. One of the signals, for example, the audio signals, is mixed first while preserving the original audio timestamps. The preserved timestamp information is then used to synchronize the timestamps of the unmixed signals, in this example the video signals, to provide synchronization of all signals. In another embodiment, the present invention uses packets containing calibration of timestamps to reduce jitter. The present invention also includes specifications for a packet for transmitting timestamp information.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.