KR100797389B1 - The cluster based streaming system and method using multiple description coding - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

The present invention relates to a cluster-based streaming system and method using multiple description coding.

2. The technical problem to be solved by the invention

The present invention encodes and stores multimedia data for a streaming service using multiple description coding, respectively, and streams each description through a dispatcher and a plurality of streaming servers when transmitting the multimedia data to a client through the Internet. This provides a cluster-based streaming system using multiple description coding to equally load between servers in a cluster and to provide services that are adaptable to client / network conditions as well as to provide continuous service in the event of some server failure. And to provide a method thereof.

3. Summary of Solution to Invention

The present invention provides a cluster-based streaming system comprising: a metadata database storing metadata such as description information of each content, streaming server information storing the description, server load information, and stream information currently being serviced; In response to a streaming service request from a client, metadata, such as description information of a corresponding content, streaming server information storing the description, server load information, and stream information currently being serviced, is received from the metadata database. A dispatcher for returning streaming server information determined based on the information (metadata) to the client; And a streaming server that stores a description of content and transmits the corresponding description by using the client information as the client information and the description file name are received from the dispatcher.

4. Important uses of the invention

The invention is used in streaming systems and the like.

Multimedia data streaming, clusters, multiple description coding

Description

The cluster based streaming system and method using multiple description coding}

1 is a diagram illustrating an embodiment of known multiple description coding;

2 is a diagram illustrating an embodiment of a cluster-based streaming server according to the prior art;

3 is a diagram illustrating a service flow in a cluster-based streaming server according to the prior art;

4 is a diagram illustrating an embodiment of a cluster-based streaming system and a service flow in the streaming system according to the present invention;

5 is a flowchart illustrating a method for providing a streaming service using multiple description coding in a cluster-based streaming system according to the present invention;

6 is a diagram illustrating an embodiment of a dispatcher node according to the present invention.

Explanation of symbols on the main parts of the drawings

100: dispatcher node 110: content distribution module

111: Server Health Checker 112: Node Agent

113: task manager 114: content transmitter

120: metadata manager 130: content streaming module

131: Scheduler 132: Client Status Checker

133: content streaming engine 200: metadata database

300: streaming server 400: client

The present invention relates to a cluster-based streaming system using multiple description coding and a method thereof. More particularly, the present invention relates to encoding and storing multimedia data for a streaming service using multiple description coding. Streaming each description through the dispatcher and multiple streaming servers when sending the multimedia data to the client via the server not only provides loads between servers in the cluster, but also provides services adaptable to client / network conditions, The present invention relates to a cluster-based streaming system using multiple description coding and a method for continuously providing a service even when a failure occurs.

In the present invention, the client refers to various terminals capable of data communication such as a wireless communication terminal, a personal computer, a notebook computer, a portable multimedia player (PMP), and the like.

In the present invention, a wireless communication terminal is a mobile communication terminal, a personal mobile communication terminal (PCS), a personal digital terminal (PDA), a smart phone, a next generation mobile communication terminal (IMT-2000), a wireless LAN terminal and the like while being carried by an individual A terminal that can communicate.

Recently, with the development of internet technology, user desire for streaming data of multimedia data (eg, video on demand) is increasing.

Streaming is a technology that optimally uses the resources of the network and the CPU by transmitting / receiving and decoding multimedia data such as video and audio in real time in real time. Long waiting time is required), so that the user can receive the service immediately upon selecting the content.

On the other hand, Multiple Description Coding is a state known as an efficient technique for robust communication over a network such as a wireless network in which multi-path interference and Doppler multiplication is performed. A known technique related to the multiple description coding will be described with reference to FIG. 1.

1 is a diagram illustrating an embodiment of known multiple description coding.

Herein, "Reliable Video Communication Over Lossy Packet Networks using Multiple State Encoding and Path Diversity (Visual communications and Image Processing, pp. 392-409, Jan. 2001, J, G. Apostolopoulos)" will be described.

Video data comprising a plurality of image frames, denoted as " 110a, 110b, 110c ", is separated into odd frames 121, 123, 125 of information and even frames 122, 124, 126 of information. The video information in each odd / even frame is independently encoded by a known encoding technique such as MPEG, and the encoded video information in the odd / even frame is used for a network using the same or different channels. Can be sent through. In this case, the information in each frame referred to as the odd frame and the even frame may be, for example, information associated with odd and even rows of video data in the video image.

Here, the cluster-based streaming server according to the prior art will be described with reference to FIGS. 2 and 3.

2 is a diagram illustrating an embodiment of a cluster-based streaming server according to the prior art.

Since one server cannot accommodate all the streaming service requests of each user, it is common to provide a service by combining multiple servers into one virtual server.

At this time, each server includes a plurality of disks, one of the servers constituting the cluster is a dispatcher. The dispatcher distributes to each server in the cluster according to a streaming service request of the user.

However, storing different content on multiple servers has the advantage of providing many kinds of content, whereas when requests for specific content are concentrated, even if there is enough capacity of the server that does not have the corresponding content, There is a drawback in that the service cannot be provided for a request exceeding the capacity of the server with the content.

In order to solve the above disadvantage, a method of replicating and storing the same content on a plurality of servers has been used, but there is a problem in that storage space is wasted and overhead due to duplication occurs.

3 is a diagram illustrating a service flow in a cluster-based streaming server according to the prior art.

As shown in FIG. 3, the cluster system according to the related art includes one dispatcher and a plurality of streaming servers, and a file server exists for installation and initial storage of content. When the user transmits the content of the content to be streamed to the dispatcher (streaming request) (1), the dispatcher selects the most appropriate server and returns the server information to the user (2). Then, the user connects to the server (access request) (3) and receives the streaming service (4).

On the other hand, the conventional technology related to improving the performance efficiency in the streaming service field will be described in detail.

As a first prior art, a Korean patent "method and system for improving transmission efficiency using multi-description layer encoding (Registration No. 10-2005-7005827)" will be described. Multiple description coding and fine granular spatial coding (Fine) As a technique for improving network transmission efficiency using Granular Spatial coding, a video image is divided into a plurality of information item frames, each frame being an independent layer encoded with a base layer and an enhancement layer. At least one communication channel is selected and each of the base layers is associated with and transmitted over one of the selected communication channels. In addition, the remaining bandwidth is determined on each associated channel, and the level of the enhancement layer corresponding to the remaining bandwidth is transmitted over the associated channel.

However, the first prior art is a technology related to network transmission efficiency, and there is a limit in that it cannot provide a scheme for reliability, load balancing, and adaptive service of a cluster system.

On the other hand, as a second prior art, "distributing content using multi-source streaming in a P2P network (published by Korea Information Processing Society Journal No. 11-A No. 5 pp.325-332, 2004.10)", In the P2P network where content distribution is very important because the subject is not fixed, the existing content sharing model plays back after downloading all the media data, so that the response time is long and the content distribution is difficult to solve in P2P multisource media streaming. By allowing the peer to play the role of the source peer at the same time as the data streaming, the user response time is shortened, and as the number of source peers participating in the media streaming increases, the bit rate is increased to increase the number of concurrent users. In addition, there is an effect that the content distribution is faster by providing a mechanism for transmitting a portion of the media file owned by the peer. In other words, by dividing the content into multiple sections, allowing a specific sending peer to transmit a specific section, and allowing a peer in charge of a quickly transmitted section to assist in the transmission of a section that has not been completed yet, content in P2P multi-source media streaming Make distribution more efficient.

By the way, the second prior art is a technology for distributing content simultaneously with streaming on a P2P network, but there is a problem that can not guarantee the stability, reliability and adaptive services of the server in providing a cluster-based streaming service .

The present invention has been proposed to solve the above problems, and when encoding and storing multimedia data for a streaming service using multiple description coding, respectively, and transmitting the multimedia data to a client through the Internet. By streaming each description through the dispatcher and multiple streaming servers, it not only balances the load among the servers in the cluster, but also provides services that are adaptable to client / network conditions, and provides continuous service in the event of some server failure. An object of the present invention is to provide a cluster-based streaming system and method using multiple description coding.

Other objects and advantages of the present invention can be understood by the following description, and will be more clearly understood by the embodiments of the present invention. Also, it will be readily appreciated that the objects and advantages of the present invention may be realized by the means and combinations thereof indicated in the claims.

The system of the present invention for achieving the above object, in a cluster-based streaming system, metadata such as description information of each content, streaming server information storing the description, server load information, stream information currently in service A metadata database stored therein; In response to a streaming service request from a client, metadata, such as description information of a corresponding content, streaming server information storing the description, server load information, and stream information currently being serviced, is received from the metadata database. A dispatcher for returning streaming server information determined based on the information (metadata) to the client; And a streaming server that stores a description of the content and transmits the corresponding description using the client information as the client information and the description file name are received from the dispatcher.

On the other hand, the method of the present invention for achieving the above object, the streaming service providing method in a cluster-based streaming system, the storage step of storing information about the description of the original content and information of each streaming server; Receiving a request for requesting a streaming service for content from a client; A reply step of returning information of the streaming server for providing the requested streaming service to the client; And a service step of providing a streaming service by transmitting a description to the client by a streaming server for providing the streaming service.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, whereby those skilled in the art may easily implement the technical idea of the present invention. There will be. In addition, in describing the present invention, when it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The present invention provides a method for maintaining the load of the entire cluster uniformly when providing a streaming service from a plurality of unshared storage devices in a cluster by using multiple description coding in providing a multimedia streaming service in a cluster-based streaming system. To present.

This allows you to provide seamless streaming services in the event of a problem with a particular server (continuously providing streaming services with low quality services) and to adapt to client and network conditions by varying the number of descriptions provided to clients. Can provide services.

In this case, the cluster-based streaming system according to the present invention is a multimedia streaming service by storing n descriptions (n is a natural number) in which the original content (stored in a separate file server) is encoded according to multiple description coding. To provide.

4 is a diagram illustrating an embodiment of a cluster-based streaming system and a service flow in the streaming system according to the present invention.

As shown in FIG. 4, the cluster-based streaming system according to the present invention stores metadata such as description information of each content, streaming server information storing the description, server load information, stream information currently being serviced, and the like. Metadata such as the metadata database 200 and the streaming service request from the client 400, the description information of the corresponding content, the streaming server information storing the description, the server load information, the stream information currently being serviced, and the like. Receive from the metadata database 200 and store the dispatcher node 100 for returning the streaming server information determined based on the received information (metadata) to the client 400, and a description of the content. The dispatcher node In response to receiving the client information and the description file name from the server 100, the streaming server 300 transmits the corresponding description using the client information.

Next, referring to FIG. 4, the service flow in the streaming system will be described. First, information of content (eg, rtsp: /) that the client 400 wants to provide a streaming service to the dispatcher node 100 according to an external input (1) is described. /123.456.789.1/Spider-Man.mpg (2), the dispatcher node 100 uses metadata (3) IP of the streaming server 300 that stores the description of the corresponding content (IP) ) Find the address (e.g. 123.456.789.20, 123.456.789.21, 123.456.789.22, 123.456.789.23) and reply.

Here, the dispatcher node 100 finds a description file name (eg, spider man) of the requested content and streaming server information storing the description using metadata. Then, the streaming server 300 transmits information (IP address) and description file name (eg, Spider-Man) of the client 400 (4). Then, each streaming server 300 transmits the corresponding description file by using the information (IP address) of the received client 400.

At this time, each streaming server 300 stores a description of the content. The metadata is stored in a separate metadata database 200.

In addition, the client 400 stores (5) streaming data (description) each received through each streaming session from each streaming server 300 in each of the separately prepared buffers, decodes and plays them. At this time, each buffer is prepared to correspond to the streaming server 300.

Meanwhile, internal components of the dispatcher node 100 and operations of the dispatcher node 100 will be described later with reference to FIG. 6.

5 is a flowchart illustrating a method of providing a streaming service using multiple description coding in a cluster-based streaming system according to the present invention.

Here, the metadata database 200 stores information on the description of the original content (description file name, etc.) and information of each streaming server 300 (IP address, server load, etc.). At this time, the description is stored according to the performance weight of each streaming server.

First, each streaming server 300 notifies (registers) its server state information to the metadata database 200 in advance (501 to 503).

Thereafter, the dispatcher node 100 receives certain content information according to a user input from the client 400 (504). In this case, the content information is for requesting a streaming service of the multimedia data, for example, when the user selects the "Spider-Man" hyperlink on the web page, it may be "rtsp: //123.456.789.1/Spider-Man.mpg". have.

Then, the dispatcher node 100 uses the metadata stored in the metadata database 200 to find out each streaming server information (eg, IP address) storing the description of the corresponding content requested for the service (505, 506. Return it to client 400 (507).

In more detail, the dispatcher node 100 requests the number of descriptions and server state information stored in the metadata database 200 in order to determine an appropriate description of the service request and the streaming server ( As a result, the number of descriptions, the description file name, the IP address of the streaming server 300, and the like are provided to determine an appropriate description number and the streaming server (506). In this case, a server name may be added. The IP address and the number of sessions of the determined streaming server 300 are returned to the client 400 (507).

In addition, the dispatcher node 100 transmits the IP address and description file name of the client 400 to the respective streaming servers 300 (508 to 510). In this case, the number of description files is equal to the number of streaming sessions.

Thereafter, each streaming server 300 transmits each description (description file) of the service-requested content to the client 400 through each streaming session (511 to 513). That is, it provides streaming data.

Then, the client 400 stores the description file received from each streaming server 300 in each buffer prepared separately, decodes, and plays the description file. In this case, each buffer may exist to match one-to-one with the streaming server 300.

6 is a diagram illustrating an embodiment of a dispatcher node according to the present invention.

As shown in FIG. 6, the dispatcher node 100 according to the present invention largely includes a content distribution module 110, a content streaming module 130, and a metadata manager 120. Here, the content distribution module 110 is used to transmit a description file from a file server (original / description storage server of content, not shown) to a streaming server, or from a streaming server to a streaming server to provide a streaming service. . In addition, the content streaming module 130 is a module for providing a streaming service to the actual client 400, the metadata manager 120 is the information (IP address, status of each streaming server 300 included in the entire cluster) Information, free disk size, etc.), and information of a description file stored in each streaming server 300 and other information.

Looking at each component in more detail, the server status checker 111 of the content distribution module 110 checks the status of each streaming server 300 periodically to determine the normal / failure status. At this time, the server state checker 111 periodically checks the state of each streaming server, stores the current performance and normal operation of the server, and informs the client of the corresponding streaming server according to the failure state. The node agent 112 is responsible for communication with each streaming server 300, and the task manager 113 manages the transfer of the description file between the streaming server or the streaming server from the file server, and the content transmitter 114 stores the actual file. It is in charge of the transmission. Here, the job manager 113 is not a person, but a device for managing a job of transferring a description file from a file server to a streaming server or a streaming server, and refers to a job manager.

The scheduler 131 of the content streaming module 130 determines a server to perform a service according to a streaming service request for the content of the client 400, and the client status checker 132 performs each of the streaming services. Monitoring the load information of the network and the client 400 between the streaming server 300 and the client, the content streaming engine 133 is responsible for the actual streaming service.

Meanwhile, if some of the n servers providing the streaming service fail during the streaming service, the server status checker 111 of the dispatcher node 100 detects this and informs the client 400 of the failed IP address. . Then, the client 400 releases the buffer for storing the data received from the failed server, and decodes and reproduces the streaming data received from another normal server. Accordingly, even if some streaming servers fail, it is possible to provide a seamless streaming service. At this time, the quality of data recognized by the user may be degraded.

The dispatcher node 100 selects servers to store the description file stored in the failed server in consideration of the use bandwidth and the performance of the server among the normal servers, and receives the file from the file server. As the transmission process is completed, the dispatcher node 100 transmits the IP address of the newly added streaming server to the client 400, and the client 400 allocates a new buffer. At this time, when the original streaming server that has failed is restored, the description file that was temporarily stored is deleted, and a service is provided through the restored original streaming server. In addition, instead of separately selecting a new server to replace the failed server, all the normal streaming servers may be shared and stored by striping each description of the failed server when the bandwidth is the same. Here, it is preferable that among the descriptions stored in the failed server, a corresponding description that is currently provided with a service is provided first.

On the other hand, when the client 400 receives the information on the type of the terminal when the streaming service request for the content, the dispatcher node 100 may determine the number of descriptions according to the type of the terminal. That is, by reducing the number of descriptions provided for a low resolution terminal such as a wireless communication terminal and the number of descriptions provided for a high resolution terminal such as a personal computer, it is possible to provide a streaming service adaptive to the user's terminal type. .

In addition, the client status checker 132 of the content streaming module 130 in the dispatcher node 100 checks the network status change and the load information of the client 400 during the streaming service, and accordingly adaptive streaming service in real time. Can be provided.

As described above, the method of the present invention may be implemented as a program and stored in a recording medium (CD-ROM, RAM, ROM, floppy disk, hard disk, magneto-optical disk, etc.) in a computer-readable form. Since this process can be easily implemented by those skilled in the art will not be described in more detail.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the technical spirit of the present invention for those skilled in the art to which the present invention pertains. It is not limited by the drawings.

The present invention as described above has the effect of maintaining the load of each streaming server evenly by using multiple description decoding in a cluster-based streaming system.

In addition, the present invention has the effect of continuously providing a streaming service with a low quality by adjusting the number of descriptions to be transmitted even if some of the streaming server is a failure.

In addition, the present invention has the effect of providing an adaptive streaming service according to the type and load degree of the terminal, the network state changes.

Claims (17)

In the cluster-based streaming system, A metadata database that stores metadata such as description information of each content, streaming server information storing the description, server load information, and stream information currently being serviced; In response to a streaming service request from a client, metadata, such as description information of a corresponding content, streaming server information storing the description, server load information, and stream information currently being serviced, is received from the metadata database. A dispatcher for returning streaming server information determined based on the information (metadata) to the client; And A streaming server that stores a description of content and transmits a corresponding description using the client information as client information and a description file name are received from the dispatcher. Cluster-based streaming system using multiple description coding comprising a. The method of claim 1, The streaming server, The cluster-based streaming system using multiple description coding, characterized in that to provide a streaming service by transmitting the description of the content requested from the client through one or more streaming sessions. The method of claim 2, The streaming server, Cluster-based streaming system using multiple description coding, characterized in that composed of one or more streaming server, each description of the content stored. The method according to any one of claims 1 to 3, The dispatcher, A content streaming module for providing a streaming service to the client; A content distribution module for performing description transmission between a file server, each streaming server, and each streaming server; And Metadata manager for managing the information of each streaming server included in the entire cluster, the description file information and other information stored in each streaming server Cluster-based streaming system using multiple description coding comprising a. The method of claim 4, wherein The content streaming module, A scheduler for determining a streaming server to perform a service according to the streaming service request from the client; A content streaming engine for providing the streaming service; And Client status checker for monitoring the load information between the streaming server and the client of the streaming service to provide a streaming service according to the monitored load information Cluster-based streaming system using multiple description coding comprising a. The method of claim 4, wherein The content distribution module, A server state checker for periodically checking and checking the state of each streaming server; A node agent for performing communication with each streaming server; A job manager for managing description transmission between the file server, each streaming server, and each streaming server; And Content transmitter to perform the actual delivery function Cluster-based streaming system using multiple description coding comprising a. The method of claim 6, The server status checker, Periodically inspect the state of each streaming server to store the current performance and normal operation of the server and to determine the failure state to inform the client of the information of the corresponding streaming server cluster-based using multiple description coding, characterized in that Streaming system. The method of claim 4, wherein The dispatcher is, The cluster-based streaming system using multiple description coding, characterized in that to determine that any streaming server of the streaming server is broken, so that the description transmitted by the streaming server through the new streaming server. The method of claim 8, The dispatcher, And the IP address of the new streaming server is transmitted to the client so that the description transmitted by the failed streaming server is transmitted to the client. The method of claim 8, The dispatcher is, A cluster-based streaming system using multiple description coding, characterized in that servers are selected to store each description file stored in the failed streaming server in consideration of the bandwidth used and the performance of the server. The method of claim 4, wherein The dispatcher is, According to the streaming service request from the client, the description number and the streaming server are determined using the description number stored in the metadata database, the description file name, and the IP address of the streaming server. Cluster-based streaming system. In the streaming service providing method in a cluster-based streaming system, A storage step of storing information about the description of the original content and information of each streaming server; Receiving a request for requesting a streaming service for content from a client; A reply step of returning information of the streaming server for providing the requested streaming service to the client; And A service step of providing a streaming service by transmitting a description to the client by a streaming server for providing the streaming service; Streaming service providing method using multiple description coding in a cluster-based streaming system comprising a. The method of claim 12, The storing step, The description is stored according to the performance weight of each streaming server. The service step, A streaming service providing method using multiple description coding in a cluster-based streaming system, characterized in that each streaming server for providing the streaming service transmits a description stored in each of the respective streaming server. The method of claim 12, The service step, As the streaming service detects a failure of any streaming server, the streaming service provided by the multi-description coding in the cluster-based streaming system, characterized in that the description transmitted by the streaming server to be transmitted through a new streaming server. Way. The method of claim 14, The service step, A method of providing a streaming service using multiple description coding in a cluster-based streaming system, wherein the new streaming server is selected according to a bandwidth used and a server performance among normal streaming servers. The method according to any one of claims 12 to 15, The storing step, The streaming service providing method using multiple description coding in the cluster-based streaming system, characterized in that for storing the IP address, status information, the free disk size as the information of each streaming server. The method of claim 16, The service step, A method of providing a streaming service using multiple description coding in a cluster-based streaming system, characterized in that a change in network state and load information of the client are checked to provide an adaptive streaming service in real time according to the checked information.

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