KR20070006318A - Videoconferencing system and method - Google Patents

Abstract

A video conferencing system and method are provided to change only IP(Internet Protocol) addresses with respect to video streams transmitted from terminals and re-transmit the video streams to remove a load and to efficiently use the bandwidth of a network. A video conferencing system includes a stream address controller(210) and a stream address converter(220). The stream address controller generates an IP address used by a first video terminal in a video conference when the first video terminal is connected to the video conferencing system and provides the generated IP address to the first video terminal. The stream address converter receives the generated IP address from the stream address controller. When the stream address convert receives a video stream from the first video terminal, the stream address converter changes the IP address of the received video stream according to the IP address provided by the stream address controller and re-transmits the video stream.

Description

Videoconferencing system and method of providing videoconferencing {Videoconferencing system and method}

1 is a configuration diagram showing the overall configuration of a videoconferencing system according to the present invention.

2 is a configuration diagram of a stream conversion platform according to the present invention.

3 is a flowchart illustrating the operation of video conferencing using the stream conversion platform according to the present invention.

The present invention relates to a videoconferencing system and a videoconferencing providing method for supporting multi-party videoconferencing. More particularly, the present invention provides a high-quality videoconferencing service by changing only an IP address of a video stream transmitted by each branch terminal and retransmitting. A video conferencing system and a method of providing an image can be provided.

A typical video conferencing system establishes two or more point-to-point connection sessions, receives and processes video (video and audio) signals from each point on the connection session, and then sends the processed video signal to other points in the conference. do. Such a device for performing signal processing and video signal exchange in a video conference system is called a multipoint control unit (MCU). The transmission of these signals is carried out in a unicast session when sending a picture of the point from each point to the multipoint control unit or when sending an edited picture from the multipoint control unit to each point. At this time, when the multi-point control unit sends the edited image to each point, the multi-point control unit may process the multicast session in order to reduce network bandwidth.

The picture provided by the existing video conferencing system is a low quality specification. The picture is less than a CIF (Common Intermediate Format) image, and the picture bandwidth does not exceed 768 kilobits per second. This is because the performance limitation of the multipoint control unit and the connection bandwidth of the branch are narrow. However, the access bandwidth of the branch is not a limiting factor at this time because broadband has already been achieved. On the other hand, since the multi-point control unit is constituted by a server which processes in software, when the transcoding (encoding after encoding) is performed in the process of editing the image signal transmitted from each point, the higher the quality of the image, the more it is used. The higher the bandwidth, the more limited the ability to handle. Even in the case of processing, the number of image processing is reduced, and there is a problem in that a large delay similar to the life of a video conference occurs.

As a solution to this problem, the recent high-quality video conferencing system, Microsoft's Conference XP, a kind of access grid, removes the multi-point control unit and uses the multicast function of the network instead. have. The multicast function is one of the functions currently being installed in the network in conjunction with the Internet Protocol TV (IP-TV). The conference XP has a structure in which a video signal at each point is transmitted using a multicast address, and a video signal transmitted from another video terminal is received.

Such a conference XP has a problem that the number of points that can participate in a video conference is limited to five due to the limitation of the capability of processing video in the video terminal. In addition, Conference XP uses two-way multicast. Due to the performance of the access equipment introduced in the network, it is difficult to mount the two-way multicast function on the network. Furthermore, having an uplink multicast feature means keeping the multicast address open on the network, which the carrier does not have on the upside multicast feature because the network is easily exposed to intentional or viral attacks. There is a tendency not to. As such, there is a problem that video conferencing services using Conference XP cannot be supported in the network.

Accordingly, an object of the present invention to solve the above problems is to improve the data transmission method for videoconferencing to provide a high quality videoconferencing service more easily in the range that the existing network can support.

A video conferencing system of the present invention for achieving the above object comprises a stream address control unit for generating an IP address for use by a first video terminal in video conferencing and providing it to the first video terminal when the first video terminal is connected; And receiving the generated IP address from the stream address controller and changing the IP address of the received image stream according to the IP address provided from the stream address controller when the image stream is received from the first video terminal. A stream address translation unit is provided.

The videoconferencing providing method of the present invention includes a first step of, upon requesting a videoconference from a first video terminal, generating an IP address to be used by the first video terminal during a videoconference and transmitting it to the first video terminal; And a second step of, upon receiving the picture stream from the first picture terminal, changing the IP address of the received picture stream according to the generated IP address and retransmitting.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

1 is a configuration diagram showing the overall configuration of a videoconferencing system according to the present invention.

The video conferencing system of FIG. 1 is comprised of video terminals 101 to 103 and a stream conversion platform 200 participating in video conferencing.

When the video terminals 101 to 103 connect to the stream conversion platform 200 for video conferencing, an IP address to be used in video conferencing, that is, an IP address to transmit its own video stream and a multicast to receive the video stream by multicast. After the IP address is allocated from the stream conversion platform 200, video conferencing between video terminals 101 to 103 is performed using the assigned address. Each image terminal 101 to 103 performs unicast transmission to the stream conversion platform 200 when transmitting an image stream, and unicast or multicast when receiving an image stream. When transmitting an image stream to each of the image terminals 101 to 103, the unicast transmission is performed by the stream conversion platform 200, and the multicast transmission is performed by the IP network 300.

When the video terminals 101 to 103 are connected for video conferencing, the stream conversion platform 200 generates and assigns IP addresses to be used for video conferencing, respectively. That is, the video terminal generates an IP address to which its video stream is to be transmitted and a multicast IP address used when receiving a video stream from another video terminal by multicast, and provides it to the connected video terminal.

FIG. 2 is a diagram illustrating in detail the configuration of the stream conversion platform 200 in FIG. 1.

The stream conversion platform 200 of the present invention includes a stream address control unit 210 and a stream address conversion unit 220.

The stream address control unit 210 generates an IP address to be used for video conferencing by the video terminal 101 connected when the video terminal 101 is connected, and then converts the generated IP address into the corresponding video terminal 101 and the stream address conversion unit. Provide to (220). That is, when the video terminal 101 is connected for video conferencing, the stream address control unit 210 has a destination IP address Us' and another address to which the connected video terminal 101 should transmit its video stream during video conferencing. After generating the multicast IP address M1 to receive the picture stream of the picture terminal 10, the picture terminal 101 and the stream address conversion unit 220 are notified. At this time, the destination IP address Us' becomes the address of the stream address translator 220. If the stream address translator 220 does not have a separate IP address, the IP address Uss of the stream address platform 200 is used. )

The stream address conversion unit 220 changes only the IP address (source address SA and destination address DA) of the video stream received unicast from the video terminals 101 to 103 while the video conference is in progress, and then unicast or multicast. After converting to a stream, an image stream is transmitted to the converted address.

3 is a flowchart illustrating a videoconferencing method using a videoconferencing system according to the present invention.

As an initial connection for video conferencing, the video terminal 101 first connects to the stream address control unit 210 (1).

The stream address controller 210 generates a transmission IP address and a reception IP address to be used by the video terminal 101 for the video conference (2). That is, the destination IP address DA for the picture stream to be transmitted by the picture terminal 101 and the multicast IP address M1 to receive the picture stream received by the multicast are generated. At this time, the destination IP address DA to which the image terminal 101 transmits the image stream becomes the IP address Us' of the stream address conversion unit 220.

The stream address controller 210 informs the generated address information to the stream address converter 220 (③).

In addition, the stream address control unit 210 informs the corresponding image terminal 101 of the generated address information (④).

The image terminal 101, which has received the address information from the stream address control unit 210, transmits its own image stream in accordance with the designated address (5). That is, the video terminal 101 is a source address (SA) for its own video stream as its own IP address (Ua), and the destination address (DA) is a stream address conversion unit (provided from the stream address control unit 210) ( An image stream is transmitted using the IP address Us' of 220.

As a result, the image stream transmitted from the image terminal 101 is transmitted to the stream address conversion unit 220.

The stream address conversion unit 220 receiving the picture stream from the picture terminal 101 should transmit the received picture stream to a specific picture terminal 102 or 103 by unicast or to the picture terminals 102 and 103. Change the IP address of the received picture stream according to whether it should be transmitted by multicast (6). For example, if the received picture stream is to be transmitted unicast to the picture terminal 102, the stream address conversion unit 220 changes the source address (SA) of the picture stream from Ua to Us "(or Us'). The destination address DA is changed from Us' to Ub (the IP address of the image terminal 102), and if the received image stream is to be transmitted by multicast to the image terminals 102 and 103, the stream address. The conversion unit 220 changes the source address SA of the picture stream from Ua to Us "(or Us ') and the destination address DA from Us' to M1. At this time, it is optional for the stream address translator 220 to change the source address to the new address Us "(Us') instead of the original source address, but in the case of multicast, if the source address is the same, the network multicast Since the tree is as simple as that, it is advisable to change the source address to the same new address.

The stream address conversion unit 220 transmits the image stream whose IP address is changed to the IP network 300 (⑦). In this case, in the case of unicast, the corresponding image stream is transmitted to the destination image terminal 102 through the IP network 300, and in the case of multicast, only the IP stream 300 is transmitted. The multicast streams transmitted only up to the IP network transmit the image stream from the IP network 300 to the corresponding video terminal only at the request of the video terminals 102 and 103.

When the video conference is to be terminated, the video terminal 101 transmits an end message to the stream address control unit 210 (8).

When the stream address controller 210 receives the end message, the stream address controller 210 deletes the data for the corresponding video terminal 101 (⑨), and requests the stream address conversion unit 220 to delete the data for the corresponding video terminal 101. Send a message to (⑩).

The stream address conversion unit 220 receiving the deletion request message from the stream address control unit 210 deletes the data for the image terminal 101 from the table (에서).

The videoconferencing mechanism described above is simply described and can be embodied in various ways. For example, in addition to the IP address of the image stream, the port number of four layers in the OSI (Open System Interconnection) model can be changed as well. In the above-described embodiment, the mechanism for showing the picture stream in the picture terminal is omitted because it has a structure capable of immediately receiving the picture requested by the picture terminal.

The stream conversion platform 200 simply changes the IP address for the input image stream and retransmits, thereby eliminating the load generated due to the image editing, etc. that the existing multi-point control server does, and does not transcode. You can increase the sex. In addition, in a network in which downlink multicast is supported, when a unicast stream is converted to a multicast stream and transmitted in a stream conversion platform, the bandwidth of the network can be used more efficiently.

As described above, the video conferencing system of the present invention simply changes the IP address and retransmits the video stream transmitted by each branch terminal, thereby eliminating the load generated due to image editing and the like which the conventional multipoint control server has done. Because it does not transcode, it can improve real time. In addition, in a network in which downlink multicast is supported, when a unicast stream is converted into a multicast stream and transmitted in a stream conversion platform, the bandwidth of the network can be used more efficiently. In addition, in a multi-party video conferencing configuration, the number of images to be output may be adjusted according to the performance of the terminal.

Claims (10)

A stream address controller configured to generate an IP address for use by a first video terminal in a video conference and provide the first video terminal to the first video terminal when the first video terminal is connected; And The stream address for receiving the generated IP address from the stream address controller and changing the IP address of the received image stream according to the IP address provided from the stream address controller when the image stream is received from the first video terminal. Video conferencing system having a conversion unit. The method of claim 1, wherein the stream address control unit And the first video terminal generates an IP address for transmitting its own video stream and a multicast IP address to be used for multicast in the video conference. The method of claim 2, wherein the stream address control unit And the first video terminal uses the IP address of the stream address conversion unit as an IP address for transmitting its own video stream. The method of claim 2, wherein the stream address conversion unit And retransmit the received video stream by changing a destination address of the video stream received from the first video terminal to the multicast IP address or the IP address of the second video terminal. The method of claim 4, wherein the stream address conversion unit And change the source address of the video streams received from the video terminals to the same new IP address. The method of claim 5, wherein the stream address conversion unit And use its IP address as the same new IP address. A first step of, upon requesting a video conference from a first video terminal, generating an IP address to be used by the first video terminal during video conferencing and transmitting it to the first video terminal; And And receiving a video stream from the first video terminal and retransmitting the IP address of the received video stream according to the generated IP address. 8. The method of claim 7, wherein the first step is And the first video terminal generates an IP address to transmit its own video stream and a multicast IP address to be used when multicasting in the video conference. The method of claim 8, wherein the second step And retransmitting the received video stream by changing the destination address of the video stream received from the first video terminal to the multicast IP address or the IP address of the second video terminal. The method of claim 9, And the source address of the picture stream received from the video terminals is changed to the same new IP address.

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