Multiplex communications – Special services – Conferencing
Reexamination Certificate
2004-07-13
2010-02-16
Ryman, Daniel J (Department: 2419)
Multiplex communications
Special services
Conferencing
C370S270000, C370S352000, C370S467000, C370S471000, C370S473000, C370S509000, C709S204000
Reexamination Certificate
active
07664057
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.
REFERENCES:
patent: 4821119 (1989-04-01), Gharavi
patent: 5640420 (1997-06-01), Jung
patent: 5751232 (1998-05-01), Inoue et al.
patent: 2003/0220971 (2003-11-01), Kressin
patent: 2004/0022262 (2004-02-01), Vinnakota et al.
patent: 2005/0180341 (2005-08-01), Nelson et al.
patent: 2005/0195860 (2005-09-01), Ollis et al.
patent: 2005/0259694 (2005-11-01), Garudadri et al.
patent: 1316957 (2003-06-01), None
RFC 3550 by Schulzrinne et al. published on Jul. 2003.
RFC 1889 by Schulzrinne et al. published on Jan. 1996.
MPEG Stream Encapsulation into RTP packets by Hazboun published on Sep. 1998.
“Real Time Protocol (RTP).”HelloSoft Inc., San Jose, CA. Available online at http://www.hellosoft.com/resources/documents/rtp.pdf Accessed on Apr. 14, 2005.
Chen Wen-hsiung
Friedrich Walter R.
Sarkar Shantanu
Wu Fang
Cisco Technology Inc.
Divecha Nishant B
Inventek
Rosenfeld Dov
Ryman Daniel J
LandOfFree
Audio-to-video synchronization system and method for... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Audio-to-video synchronization system and method for..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Audio-to-video synchronization system and method for... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-4173845