KR20050047228A - Mutlticasting serivce method of high density internet broadcast system - Google Patents

Abstract

The present invention relates to a multicast service method in a high-definition internet broadcasting system capable of appropriately providing a real-time broadcasting service of HDTV contents in accordance with a network state through the Internet. The present invention relates to an Internet broadcasting system comprising a plurality of clients, a service broker, and a media gateway. In the service system, a multicast group in which a plurality of multicast groups divided by different bit rates for each content is set in the media gateway, the available bandwidth of a client requesting the broadcast service is measured, and an appropriate bit rate is set according to the available bandwidth. By providing the address to the client, it is possible to receive streaming service at an appropriate bit rate according to the network condition on the client side, and as a result, it is possible to reduce the occurrence of service interruption or suspension due to deterioration of the network condition. Can be.

Description

Multicast service method of high-definition internet broadcasting system {Mutlticasting serivce method of high density internet broadcast system}

The present invention relates to a high-definition Internet broadcasting system for serving HDTV content through the Internet. More particularly, the present invention provides a streaming service by controlling the bit rate at an appropriate bit rate according to the state of a network connecting a broadcast server and a client. The present invention relates to a multicast service method in a high-definition Internet broadcasting system capable of providing quality of service.

Internet broadcasting service refers to a service that provides multimedia data such as video and audio data to viewers in real time or on-demand through the Internet. The Internet broadcasting service uses a streaming technique that can play data through a browser even if the client does not receive all the data files. In addition, the streaming service includes a unicast scheme in which a sender transmits data to only one receiver and a multicast scheme in which a sender transmits data to a specific number of receiver groups.

By the way, even though most of the currently provided Internet broadcasting services are intended for a large number of recipients, they rely on the unicast scheme, and thus, use of a huge bandwidth in the network, inefficient use of the broadcast transmission system, The problem of limiting the number of simultaneous users is caused, and the overlapping transmission of unicast traffic causes overload and bottleneck of the network, resulting in deterioration of overall network service quality.

In addition, the existing Internet broadcasting system based on the unicast method has a problem that the number of concurrent users that can provide a service is limited due to the limitation of increasing the load on the broadcast server and the network.

In addition, since the Internet broadcasting service that can use some multicast schemes does not reflect the current state of the network, and simply joins a multicast group, the broadcast server receives a transcoded stream at a constant bit rate from the broadcast server. When the state of the network between the broadcast server and the client, for example, the transmission speed, bandwidth allocation, and load conditions deteriorate, problems such as playback pause and broadband service may occur, thereby degrading service quality. have.

The present invention has been proposed to solve the above-mentioned problems, and an object thereof is to provide a streaming service by adjusting HDTV-class content at an appropriate bit rate according to a state of a network connected to a client, thereby providing a high quality that can maintain stable service quality. The present invention provides a multicast service method in an internet broadcasting system.

As a configuration means for achieving the above object of the present invention, the present invention provides a high-definition Internet consisting of a media gateway for transmitting streaming data to one or more clients and a service broker serving as a broker for the services of the media gateway to the plurality of clients. In the multicast service method of a broadcasting system,

An initialization step of identifying a plurality of multicast groups for providing streaming data transcoded at different bit rates for each content to be serviced;

A service request step of requesting a service for a predetermined content by accessing a service broker from a client:

A bandwidth measurement step of measuring available bandwidth between a client requesting the service and a media gateway providing the service:

Selecting a multicast group of the corresponding content having a bit rate serviceable by the client based on the available bandwidth measured in the bandwidth measuring step and providing the address to the client; and

Joining the multicast group of addresses provided by the client;

And transcoding and streaming the stream of the corresponding content for each multicast group at a designated bit rate in the media gateway, and providing the appropriate bit rate streaming data according to the network condition between the media gateway providing the content and the client. It is possible to prevent situations such as suspensions or interruptions in service, and to provide stable service quality.

In addition, in the high-definition internet broadcasting service providing method according to the present invention, the initialization step is

Dividing the variable range of the bit rate that can be provided by the media gateway into n classes;

Setting a range of available bandwidths and reference bit rates corresponding to the classes; And

And specifying a multicast group corresponding to the plurality of divided classes for each content.

In addition, in the high-definition Internet broadcasting service providing method according to the present invention, the bandwidth measuring step

Transmitting a plurality of bit rate sample data from the service broker to a client requesting a service; Waiting for a response from the client transmitting the sample data; And

When the response message according to the reception of the sample data is received from the client in the standby state, it may be a step of estimating the available bandwidth between the media gateway and the client therefrom.

In addition, in the high-definition Internet broadcasting service providing method according to the present invention, the bandwidth measuring step

Requesting an available bandwidth measurement for a client requesting a service from the service broker to a media gateway;

Transmitting a plurality of bit rate sample data from the media gateway receiving the request to a corresponding client, and waiting for a response accordingly;

When the response message according to the reception of the sample data is received from the client in the standby state, it may be a step of estimating the available bandwidth between the media gateway and the client therefrom.

In addition, the present invention provides a computer-readable recording medium recording a program for performing each step of the method for providing a high quality broadcast service.

Hereinafter, a multicast service method according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram showing a schematic configuration of a high-definition Internet broadcasting system to which the service providing method according to the present invention is applied.

As shown in FIG. 1, the high-definition internet broadcasting system includes a client 1 using an internet broadcasting service, user authentication, profile management, session and state information management, and content list according to the client 1's request. A service broker 2 that performs a function and a media gateway 3 that provides a streaming service for the selected content to the corresponding client 1 in response to a request of the service broker 2.

Here, the client 1 may include a service request module 11 and a service request module 11 that perform a function of allowing a user who wants to watch a high definition Internet broadcast to request a service through a web page of a service broker. A media player module 12 that plays the Internet broadcast of the received stream when the stream of content requested by the media gateway 3 is delivered, the service broker 2 being provided by the media gateway 3. Web server module 21 for providing web-based information on high-definition Internet broadcast contents, and bandwidth monitoring module for measuring available bandwidth between the client 1 and the media gateway 3 requesting the Internet broadcasting service. (22), the available bandwidth measured by the bandwidth monitoring module 22 and the controller requested by the client (1). Service request module 23 which transmits the information about the information to the media gateway 3, receives the corresponding multicast group address, and delivers the information to the client 1, and the media gateway 3 includes the When receiving a service request from the service broker 2, the service control module 31 selects an appropriate multicast group according to the available bandwidth with the client and provides the address of the multicast group to the service broker 2; IP streaming for performing a streaming service to a transcoding module 32 performing transcoding for the requested content and a client 1 of a multicast group corresponding to a stream provided from the transcoding module 32. Module 33, which modules comprise the corresponding devices, i.e., the client 1, the service broker 2, and the media gay. In the way (3) it may be implemented in software form. The plurality of clients 1, the service broker 2, and the media gateway 3 are connected to the Internet 4.

The transcoding module 32 of the media gateway 3 can transcode 19.24 Mbps MPEG-2 source data at a bit rate of 19.24 Mbps to 384 Kbps. In the present invention, the available bandwidth of the network corresponding to the variable range of the bit rate that can be accepted by the media gateway 3 is divided into n (n is a natural number of 1 or more) areas, and the appropriate bit rate of transcoding is set for each area. In this case, a multicast group for providing transcoded streaming data is set for the same content.

That is, in the Internet broadcasting service according to the present invention, a multicast group for providing streaming data corresponding to each content is set, and the same content is also classified by dividing the multicast groups by the set bit rates. It is possible to provide a plurality of streaming data having different bit rates. The above operation is performed in the initialization step of the media gateway 3.

Accordingly, the media gateway 3 can perform a streaming service at an appropriate bit rate according to the load condition of the Internet connecting the clients 1 requesting service. In other words, when the available bandwidth is narrow, the streaming data having a low bit rate acceptable for the bandwidth is provided, and when the available bandwidth is wide, the streaming data is provided at the maximum bit rate acceptable for the bandwidth, so that the client 1 It is possible to provide a broadcast service of image quality.

2 illustrates an overall service performing procedure in the internet broadcasting system configured as described above. Referring to this, an internet broadcasting service providing procedure according to the present invention will be described below.

As shown in Fig. 2, in the Internet broadcasting system according to the present invention, a client (1) 1 who wants to receive a streaming service for high-definition broadcasting accesses a web page provided by the service broker 2, Selects a channel for broadcasting desired content. Accordingly, a service request for predetermined content is made from the service request module 11 of the client 1 to the service broker 2 (s1).

Upon receiving this, the service broker 2 monitors the available bandwidth between the client 1 requesting the service and the media gateway 3 capable of providing the service, and monitors the available bandwidth monitored with the service request of the client. The service request is transmitted by transmitting to the gateway 3 (S2).

The media gateway 3 determines whether the requested service can be provided, and if it is impossible, indicates that the service is unavailable in the service response message and delivers it to the service broker 2 (s3), which is the service broker 2. Is sent back to the client 1 (s4).

On the contrary, if the requested service is available, the media gateway 3 based on the information provided from the service broker 2, the corresponding content transcoded at a bit rate suitable for the state of the current network, that is, the available bandwidth. The address of the multicast group transmitting the streaming data of the service broker 2 is transmitted to the service broker 2 (s3), and the address is transferred from the service broker 2 back to the client 1 (s4).

As such, the client 1 receiving the address of the multicast group of the desired channel joins the multicast group and receives the transcoded streaming data at a predetermined bit rate provided from the media gateway 3. At this time, the bit rate of the streaming data provided by the media gateway 3 has an acceptable range in the available bandwidth of the network connected to the client 1 as described above. Accordingly, the streaming service delivered from the media gateway 3 to the client 1 can be continued without interruption, and the received streaming data is reproduced by the media player module 12 mounted on the client 1.

3 is a flowchart showing the overall operation of the Internet broadcasting service method according to the present invention.

Referring to FIG. 3, the Internet broadcasting service system according to the present invention first divides the range of the available bit rate and the available bandwidth corresponding to the predetermined class, and provides the maximum acceptable bit rate and each streaming data for each class. A cast group is set (s301). Step 301 is performed as an initialization step before the Internet broadcasting service is started.

Next, the web server module 21 of the service broker 2 is operated to display information on the content of the service through the web page (S302). When a service request is made from the client 1 using the web page thus provided (s303), the service broker 2 checks whether the media gateway 3 is currently serviceable (s304). Here, if the service is not available in the media gateway 3, the client 1 is notified that the service is currently unavailable (s305). If the service is available, the network state between the media gateway 3 and the client 1 is not present. According to the available bandwidth is measured (s306). Then, the available bandwidth measured by the above and the information on the content selected by the client 1 is delivered to the media gateway 3 to request a service, and then waits for a response (s306). When a response is received from the media gateway 3, the multicast address transmitted through the media gateway 3 is transmitted to the corresponding client 1 (s307), so that the multicast group can be joined to the multicast group. In addition, the client 1 receiving the address of the multicast group capable of receiving the service of the desired content is subscribed to the corresponding group (s308), and as a result, the streaming data of the desired content is provided at an acceptable bit rate in the available bandwidth. (s309).

As described above, the multicast group joining procedure of the client 1 based on the address of the multicast group and the streaming service of the selected content from the media gateway 3 to the client 1 are generally known.

In the above, the measurement of the available bandwidth according to the network situation between the client 1 and the media gateway 3 requesting the service, the sample data of a predetermined bit rate is transmitted from the service broker 2 to the client 1, accordingly This can be done by estimating the available bandwidth at the client 1 from the response message from the client 1. Further, at the request of the service broker 2, the media gateway 3 directly transmits sample data of a predetermined bit rate to the client 1, receives a response message from the client 1, and uses available bandwidth. Can be estimated. Here, the latter method can measure the more accurate available bandwidth, but it can increase the burden on the media gateway 3, while the former method can estimate the approximate available bandwidth without the burden of the media gateway (3). There is an advantage that it can. Appropriate methods can be applied as necessary.

4 illustrates a state in which clients requesting a service are subscribed to a corresponding multicast group to receive a service, and there are three groups 41 to 43 belonging to a multicast group for the same channel. When the small groups 41 to 43 are connected to the media gateway 3, the small groups 41 to 43 are formed according to clients having similar available bandwidths, and the three groups 41 to 43 receive streaming services for the same channel. 41-43) will receive the transcoded content at different bit rates associated with the available bandwidth.

The present invention described above may be embodied as computer readable codes on a computer readable recording medium, wherein the computer readable recording medium includes all kinds of recording media storing data that can be read by a computer. For example, it may be a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, or the like. In addition, the present invention may be in the form of a carrier wave that can be transmitted through the Internet, or may be distributed and executed in a computer system connected through a network.

As described above, according to the present invention, when providing a broadcast service using the Internet, a load problem of a network and a server can be solved using a multicast method, and at the same time, a transmission rate is set based on an available bandwidth between a client and a media gateway. By delivering the coded stream to the client, it is possible to receive the appropriate high-definition internet broadcasting service according to the network situation. Also, by using the multicast technique, the number of simultaneous viewers can be infinitely expanded, and the load of the media gateway and the network is significantly increased. There is an excellent effect that can be reduced.

1 is a structural diagram of a high definition internet broadcasting system to which the present invention is applied.

2 is a service flowchart of a high definition internet broadcasting system.

3 is a flowchart illustrating a multicast service method in a high definition internet broadcasting system according to the present invention.

4 is an embodiment of an internet broadcasting system in which a multicast service is provided according to the present invention.

Claims (5)

In the multicast service method of a high-definition Internet broadcasting system consisting of a media gateway for transmitting streaming data to at least one client and a service broker serving as a broker for the services of the media gateway to the plurality of clients, Initiating and separating a plurality of multicast groups for providing streaming data transcoded at different bit rates for each content provided by the media gateway; A service request step in which a client accesses a service broker and requests a service for predetermined content: A bandwidth measurement step of measuring available bandwidth between a client requesting the service and a media gateway providing the service: Providing the client with its address selecting a multicast group of the corresponding content having a bit rate serviceable by the client based on the available bandwidth measured in the bandwidth measuring step: Joining the multicast group of addresses provided by the client; And transcoding and streaming a stream of corresponding content for each multicast group at a specified bit rate in the media gateway. The method of claim 1, wherein the initialization step Dividing the variable range of the bit rate that can be provided by the media gateway into n classes; Setting a range and a reference bit rate of the available bandwidth corresponding to each class; And And specifying a multicast group corresponding to the divided plurality of classes for each content. The method of claim 1, wherein the bandwidth measuring step Transmitting a plurality of bit rate sample data from the service broker to a client requesting a service; Waiting for a response from the client transmitting the sample data; And Estimating available bandwidth between the media gateway and the client from the client when a response message is received from the client in the standby state; Multicast service method in a high-definition Internet broadcasting system, characterized in that consisting of. The method of claim 1, wherein the bandwidth measuring step Requesting an available bandwidth measurement for a client requesting a service from the service broker to a media gateway; Transmitting a plurality of bit rate sample data from the media gateway receiving the request to a corresponding client, and waiting for a response accordingly; Estimating available bandwidth between the media gateway and the client from the client when the response message is received from the client in the standby state. A computer-readable recording medium having recorded thereon a program for performing each step according to claim 1.