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System and method for providing synchronized Web conferences Disclosure Number: IPCOM000191070D
Original Publication Date: 2009-Dec-15
Included in the Prior Art Database: 2009-Dec-15
Document File: 7 page(s) / 127K

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The present invention relates to a method for getting the participants synchronized with the presenter in a web conference. When web conference is hold accross the Internet, the synchronization between the presenter and participants may be a problem. Due to various network reasons, participants often have different speeds to get the presentation, some fast and some slow. Sometimes the presenter is prone to page the presentation without recognizing that some participants haven't even got the last page. For example, when a sametime web conference is hold between China and U.S. teams, China team often has problems to keep synchronized with the U.S. presenter using a narrow connection. Saving bandwidth is a known solution to improve the performance of web conference. Some applications sacrifice the quality of the content to acquire quicker data transmitting, such as compressing the image data from 1024*768 to 640 * 480, reducing the frames of images and so on. Though the participants get synchronized better in these ways, but what they've got are different from the presenter's. As a result, the participants have a bad experience with the presentation and are not guarded to keep synchronized with the presenter. Some applications combine data in the route like multiplexing to get better performance. This solution does save the network load and reduces the delay of transmitting data to some extent. But if one participant has a narrow-band connection to the conference server, it doesn't help much. The weak client still has problems to keep synchronized. To solve the problems above, this invention provides a method in which the slow participants will retrieve supplementary data segments from fast ones. This will help to keep all participants synchronized with the presenter in a maximum extent in real-time.

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System and method for providing synchronized Web conferences

The key idea of this invention is to provide a mechanism for the slow participants in a Web conferencewho are lagging behind the presentation to retrieve the supplementary data stream from the selected fast participants, so that they can reducethe lagging time and stay in sync with the presenter.

When the presenter shares his/her presentation materials (a presentation file, presenter's desktop, a live demo, etc) with the participants through the Web conference system, the Web conference server keeps detecting and monitoring the bandwidth of all connected participants by collecting the data stream transfer time of all the Web conference clients used by participants. Upon receiving the video data stream from the presenter, the Web conference server first divides each frame of the data stream into a number of data segments basedon the configurable policy. Then, it transfers the data stream in form of segment to each participant's Web conference client, which will send back a transfer completion signal after it successfully receives a segment. Based on the gathered data stream transfer time of all the participants over a period of time, the Web conference server identifies those slow participants who are lagging behind the presentation, as well as the fast participants who can retrieve the data stream without having significant delay. The data stream transfer completion status of all participants will also been shown in the presenter's Web conference client, which can help the presenterto control the presentation speed when he/she progresses.

During the Web conference, in order to bring all the participants in sync with the presenter, the Web conference server leverages those fast participants to provide supplementary data stream to those slow participants by allowing Web conference clients to establish supplementary data segments transfer connections. The Web conference server locates one or more matched fast participantsfor each slow participant based on rules, and then it provides the fast participant information to each slow participant so that it can directly establish the supplementary data segments transfer connections with the given fast participants. When the presenter progresses in a Webconference, a participant first retrieves the unique segment IDs of each frame, and then it downloads segments not only from the Web conference server, but also from the connected fast participants. The fast participants can work in an active mode which means they will notify the slow participants with the completed segment IDs information. They can also work in a passive mode in which they wait for the slow participant to query the completed segment information. If slow participants find the appropriate segments which are available on connected peers but are not...