System and method for data streaming and synchronization in multimedia groupware applications

• US 6,321,252 B1
• Filed: 07/17/1998
• Issued: 11/20/2001
• Est. Priority Date: 07/17/1998
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Bhola, Sumeer, Willebeek-LeMair, Marc Hubert, Doddapaneni, Srinivas Prasad, Mukherjee, Bodhistattwa, Kumar, Keeranoor Ganapathy
• Primary Examiner(s): Coulter, Kenneth R.
• Application Number:
  US09/118,517
• Time in Patent Office: 1,222 Days
• Field of Search: 709/204, 345/330, 345/331, 345/332, 370/260
• US Class Current: 709/204
• CPC Class Codes: H04N 21/234 Processing of video elementary streams, e.g. splicing of video streams or manipulating encoded video stream scene graphs
• CPC Class Codes: H04N 21/43072 of multiple content streams on the same device
• CPC Class Codes: H04N 21/4788 communicating with other users, e.g. chatting arrangements for providing for computer conferences, e.g. chat rooms, to substation in data switching networks H04L12/1813; distributed application using peer-to-peer [P2P] networks H04L67/104
• CPC Class Codes: H04N 7/15 Conference systems

Abstract

A system and method for temporal synchronization of media streams in multimedia collaborative applications (i.e., a multi-user distributed applications used for interaction, both in the synchronous and asynchronous fashion among a group of users) in a wide-area distributed environment. The invention presents two abstractions; event streams and collaboration space, that together provide for coarse-grained temporal synchronization by using separate streams for different media and synchronizing the streams at the client location. VCR-like controls are also provided on groups of components in a collaborative application. The event stream provides many services such as replication, persistence, buffering, reading, and writing to archive. By implementing simple interfaces, existing collaborative applications, media players, and encoders become components that can be used to build complex multimedia collaborative applications. To efficiently implement a seeking function on a data component, the present invention introduces a framework for application-specific updates to a component state.

Claims

1. A system for providing collaboration among a multi-user distributed computing environment comprising:

a local client computer having first collaboration space comprising at least one first stream;

a plurality of remote client computers each having remote collaboration space comprising a replica of said at least one first stream;

at least one server for serving said local and said plurality of remote client computers, said serving comprising handling of information relating to said at least one first stream among said at least one local and said plurality of remote client computers; and

network means connecting said at least one server and said client computers.

2. The system of claim 1 wherein said at least one first stream comprises at least one event stream.

3. The system of claim 2 wherein said server further comprises at least one stream object for serving said at least one event stream.

4. The system of claim 2 further comprising at least one media stream.

5. The system of claim 4 further comprising a reflector server for serving said at least one media stream.

6. The system of claim 3 wherein said at least one stream object comprises:

at least one event buffer;

at least one event sequence generator;

registry list of associated client computers; and

event distributor means.

7. The system of claim 4 wherein said each of said client computers comprises:

operating system layer;

middleware layer; and

application layer, and wherein said application layer comprises at least said collaboration space having data components and media components.

8. The system of claim 7 wherein said middleware layer comprises multimedia collaborative client component comprising at least said event stream, said media stream and coordinator means.

9. The system of claim 8 wherein said coordinator means comprises at least one clock object and component registry.

10. The system of claim 9 wherein said at least one clock object comprises a source clock object and a sink clock object.

12. The system of claim 8 wherein said coordinator means comprises at least one control event distributor to receive and distribute a plurality of control events.

13. The system of claim 5 wherein said reflector comprises at least one buffer and network connection means for each client.

14. The system of claim 7 wherein each of said client computers additionally comprises an event queue for queuing said event streams.

11. The system of claim 11 further comprising a client clock selection policy at said client coordinator.

15. A method for providing for collaboration among users at client computers, each of said client computers having at least one data component, on a client-server network having at least one local client computer, a plurality of remote client computers and at least one server for serving said at least one local client computer and said Plurality of remote client computers by handling information relating to said at least one first stream among said at least one local and said plurality of remote client computers comprising the steps of:

creating an event stream at a first data component on a first of said client computers; and

providing said event stream to a first server for said server to handle said event stream among said at least one local and said plurality of remote client computers.

16. The method of claim 15 wherein said creating said event stream further comprises specifying if said event stream is to be shared and wherein said first server creates a stream object for said event stream.

17. The method of claim 16 further comprising at least one of said data components on a requesting one of said at least one of said remote client computers requesting a replica of said event stream and wherein said server replicates said event stream.

18. The method of claim 17 wherein said replicating comprises the steps of:

said stream object sending the current state of the event stream, comprising said replica, to said requesting client computer;

said stream object registering said replica for update notification;

creating an event stream replica at said requesting client computer; and

initializing an event queue at said requesting client computer.

19. In a client server system comprising at least one first local client computer having an event stream replicated in at least one event stream replica located in at least one remote client computer, each of said client computers having at least one data component and an event queue and being associated with at least one server having a stream object associated to said event stream, a method for posting an event from said event stream comprising the steps of:

said event stream attaching a sync marker to said event;

said event stream sending said event and said sync marker to said stream object on said at least one server;

said stream object attaching a sequence number to said event; and

said stream object multicasting said event to said at least one event stream replica.

20. The method of claim 19 further comprising receiving said event at said at least one event stream replica and updating said event queue using said sequence number.

21. The method of claim 19 further comprising synchronizing said at least one event stream replica to said event stream.

22. In a client server system comprising at least one first local client computer having an event stream replicated in at least one event stream replica located in at least one remote client computer, each of said client computers having at least one data component and an event queue and being associated with at least one server having a stream object associated to said event stream, a method for updating said event stream comprising the steps of:

said at least one first local client computer communicating updated event stream to said stream object; and

said server communicating said update to each of said at least one event stream replica.

23. The method of claim 22 wherein at least one of said client computers comprises at least one media stream and at least one other of said client computers has at least one media stream replica, and wherein said system further comprise at least one reflector server, a method for updating said media stream comprising the steps of:

said at least one client computer updating said media stream;

said at least one client computer communicating said updated media stream to said reflector server; and

said reflector server multicasting said updated media stream to said at least one media stream replica.