Method and system for providing site independent real-time multimedia transport over packet-switched networks
First Claim
1. A system for providing site independent real-time multimedia transport over packet-switched networks comprising:
- a network;
a first node selected from a group of nodes wherein said first node is coupled with said network and wherein said first node comprises;
a packet store;
an automatic repeat request module coupled with said packet store;
a time clock; and
, a timing synchronizer configured to time stamp a first packet and a second packet obtained from said automatic repeat request module with a time parameter obtained from said time clock;
a plurality of second nodes selected from said group of nodes wherein said plurality of second nodes are coupled with said network and wherein said plurality of second nodes comprises;
a receiver time clock;
a receiver timing synchronizer coupled with said receiver time clock;
a clock recovery module coupled with said receiver timing synchronizer;
a receiver automatic repeat request buffer;
a receiver automatic repeat request module coupled with said receiver automatic repeat request buffer;
said first node configured to transmit to said plurality of said second nodes; and
, said plurality of second nodes configured to restore packet order, remove jitter and recover lost packets and where said each of said plurality of second nodes further comprise a network monitor configured to calculate and update a minimum hold time based on network jitter and round-trip time.
1 Assignment
0 Petitions
Accused Products
Abstract
Embodiments of the invention enable minimum latency site independent real-time video transport over packet switched networks. Some examples of real-time video transport are video conferencing and real-time or live video streaming. In one embodiment of the invention, a network node transmits live or real-tine audio and video signals, encapsulated as Internet Protocol (IP) data packets, to one or more nodes on the Internet or other IP network. One embodiment of the invention enables a user to move to different nodes or move nodes to different locations thereby providing site independence. Site independence is achieved by measuring and accounting for the jitter and delay between a transmitter and receiver based on the particular path between the transmitter and receiver independent of site location. The transmitter inserts timestamps and sequence numbers into packets and then transmits them. A receiver uses these timestamps to recover the transmitter'"'"'s clock. The receiver stores the packets in a buffer that orders them by sequence number. The packets stay in the buffer for a fixed latency to compensate for possible network jitter and/or packet reordering. The combination of timestamp packet-processing, remote clock recovery and synchronization, fixed-latency receiver buffering, and error correction mechanisms help to preserve the quality of the received video, despite the significant network impairments generally encountered throughout the Internet and wireless networks.
-
Citations
19 Claims
-
1. A system for providing site independent real-time multimedia transport over packet-switched networks comprising:
-
a network;
a first node selected from a group of nodes wherein said first node is coupled with said network and wherein said first node comprises;
a packet store;
an automatic repeat request module coupled with said packet store;
a time clock; and
,a timing synchronizer configured to time stamp a first packet and a second packet obtained from said automatic repeat request module with a time parameter obtained from said time clock;
a plurality of second nodes selected from said group of nodes wherein said plurality of second nodes are coupled with said network and wherein said plurality of second nodes comprises;
a receiver time clock;
a receiver timing synchronizer coupled with said receiver time clock;
a clock recovery module coupled with said receiver timing synchronizer;
a receiver automatic repeat request buffer;
a receiver automatic repeat request module coupled with said receiver automatic repeat request buffer;
said first node configured to transmit to said plurality of said second nodes; and
,said plurality of second nodes configured to restore packet order, remove jitter and recover lost packets and where said each of said plurality of second nodes further comprise a network monitor configured to calculate and update a minimum hold time based on network jitter and round-trip time. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
-
-
13. A method for providing site independent real-time multimedia transport over packet-switched networks comprising:
-
encapsulating multimedia data as a first packet and a second packet;
combining said first packet and said second packet into a stream of packets;
stamping said first packet and said second packet with a time stamp and a sequence number; and
,transmitting said stream of packets over an network to a plurality of receivers. - View Dependent Claims (14, 15)
-
-
16. A method for providing site independent real-time multimedia transport over packet-switched networks comprising:
-
stamping a first packet, a second packet and at least one forward error correction packet with a time stamp of a time of arrival;
recovering a transmitter clock;
buffering said first packet, said second packet and said at least one forward error correction packet;
ordering said first packet and second packet based on a sequence number in said first packet and said second packet;
holding said first packet and said second packet in a buffer for a fixed latency to compensate for calculated network jitter;
removing said first packet and said second packet from said buffer and placing said first packet and said second packet in an error correction buffer for a fixed time;
recovering a first lost packet;
requesting resend of a second lost packet; and
,displaying multimedia using data obtained from said first packet, said second data packet, said first lost packet and said second lost packet. - View Dependent Claims (17, 18, 19)
-
Specification