KR101125065B1 - System and Method for Providing Streaming Service Using Hierarchical Distributed Storing Structure - Google Patents

Abstract

The present invention relates to a streaming service providing system and method using a hierarchical distributed storage structure. The present invention utilizes a hierarchical distributed storage structure of cache servers. The first and last portions of streaming content are distributed and stored in a cache server that is far from a short distance from a client in transmission time, and requests a streaming service from a client. The cache server of the near and far distances sequentially transmits the first part to the last part of the streaming content, and the client sequentially receives the first part and the last part of the streaming content to play while buffering. Therefore, the present invention can smoothly provide a high quality streaming service by reducing the initial buffering time.

Streaming, multimedia content, cache server, initial buffering delay, hierarchical distributed storage

Description

System and Method for Providing Streaming Service Using Hierarchical Distributed Storing Structure}

The present invention relates to a streaming service, and more particularly, in the hierarchical distributed server structure in which cache servers of multiple layers are distributed between a content server and a client, when each content is divided into multiple segments and distributed and stored in multiple cache servers. The present invention relates to a streaming service providing system and a method capable of reducing an initial buffering delay by storing segments which are played first in time in a lower layer closer to a client.

With the development of internet technology, a streaming service that receives multimedia content such as video or animation through the internet in real time is being activated. Streaming refers to a technique of playing in real time while buffering a certain amount of the entire file, unlike a download method of playing after receiving all multimedia content files. Since the rest is continuously transmitted while playing back the buffered part, it is called 'streaming' because the transmitted data is treated as if it were a continuous, continuous stream of water. Such streaming services include real time broadcast services or video on demand services.

Meanwhile, with the explosive increase in video content including user created contents (UCC), Internet traffic has been increasing rapidly in recent years. The growth rate of Internet bandwidth (supply) is not able to keep pace with the growth rate of Internet traffic (demand). In 2007 alone, global Internet traffic grew 75 percent, but Internet bandwidth grew only 44 percent.

As a way to solve the shortage of Internet bandwidth, CDN (content delivery network) technology is attracting attention. CDN technology is a technology that can utilize the internet network more efficiently by using active traffic distribution to increase average network utilization and lower peak traffic. According to the CDN technology, the content provider replicates the content to be provided to the client to a plurality of locally distributed servers, and when requested by the client, the content provider can receive the content from the optimal server.

However, in the case of a streaming service mainly targeting a large amount of multimedia content, playback is started only after storing a sufficient amount of data in a client terminal at the beginning of streaming to seamlessly service the streaming content. In other words, the initial buffering process must be performed. Therefore, in general streaming service, the delay caused by initial buffering cannot be avoided. Moreover, when the network transmission environment is poor or the receiving environment of the end user is poor, this initial buffering delay becomes a more serious problem and the quality of service (QoS) ) Acts as a factor to lower.

Accordingly, the present invention is to solve the conventional problems, to smoothly provide a high-quality streaming service by reducing the initial buffering time in the streaming service of multimedia content.

In addition, the present invention is to provide a method that can efficiently utilize the limited network resources in the streaming service of multimedia content.

In order to achieve this object, the present invention provides a streaming service providing system and method using a hierarchical distributed storage structure.

The streaming service providing system according to the present invention includes a content server for storing streaming content and serving the stored streaming content; The first and last parts of the streaming content are distributed and stored in correspondence with the shortest distance from the closest distance from the first part of the streaming content. A plurality of cache servers sequentially transmitting the last portion; And a client that sequentially receives and buffers the first to last portions of the streaming content, and plays the buffered streaming content.

In the streaming service providing system using the hierarchical distributed storage structure of the present invention, the first part to the last part of the streaming content is composed of a plurality of hierarchical files for dividing the streaming content in a playback order, and the plurality of hierarchical files These include a layer header and layer data, and the layer header may have link information of another layer file according to a playback order.

Also, when n is a natural number, the plurality of cache servers are configured as cache servers of the first to nth layers from a close distance in time with the client, and the first to last parts of the streaming content are n, and the first part. From the first to the n-th layer cache server may be distributed and stored sequentially.

In addition, streaming content distributed and stored in the first layer cache server may have a file larger than or equal to the size required for the initial buffering of the client.

On the other hand, the streaming service providing method according to the present invention uses a hierarchical distributed storage structure of the cache servers, the first to the last portion of the streaming content is a cache server far from a close distance in the transmission time with the client of the cache servers Storing in a distributed manner; When a streaming service request is made from a client, sequentially transmitting a first part to a last part of the streaming content by a cache server far from the short distance; And receiving, buffering, and playing the buffered streaming content by the client sequentially receiving the first to the last part of the streaming content.

In the streaming service providing method using the hierarchical distributed storage structure of the present invention, the first part to the last part of the streaming content is composed of a plurality of hierarchical files for dividing the streaming content in a playback order, and the plurality of hierarchical files These include a layer header and layer data, and the layer header may have link information of another layer file according to a playback order.

Also, when n is a natural number, the plurality of cache servers are configured as cache servers of the first to nth layers from a close distance in time to the client, and the first to last parts of the streaming content are n to the first part. Sequentially distributed to the first to n-th layer cache server.

In addition, streaming content distributed and stored in the first layer cache server may have a file larger than or equal to the size required for the initial buffering of the client.

According to the present invention, when distributed content is stored in a hierarchical distributed server structure, the content segment played first in time is stored in a lower layer closer to the client, thereby effectively reducing the initial buffering delay.

In addition, the present invention has the advantage that can efficiently utilize limited network resources in the streaming service and improve the quality of service (QoS).

Hereinafter, with reference to the accompanying drawings will be described in detail an embodiment of the present invention. In describing the embodiments, descriptions of technical contents that are well known in the art to which the present invention pertains and are not directly related to the present invention will be omitted. This is to more clearly communicate without obscure the core of the present invention by omitting unnecessary description. On the other hand, the same reference numerals are assigned to the same or corresponding components throughout the accompanying drawings.

1 is a diagram schematically illustrating a hierarchical distributed storage structure of a streaming service providing system according to an exemplary embodiment of the present invention.

Referring to FIG. 1, a streaming service providing system includes a content server 100 storing an original content, a plurality of cache servers 200 storing a copy of content, a content server 100, and cache servers 200. It is configured to include a client 300 receiving a streaming service.

The content server 100 is a server that stores the original of the streaming content, and provides the streaming content to the subscriber client (300). In this case, the content server 100 may provide a streaming service to the client 300 through the plurality of cache servers 200. To this end, the content server 100 provides copies of its content to the plurality of cache servers 200.

The client 300 is a subscriber client that subscribes to a streaming service provided by a content server. The client 300 is provided with a streaming service from the content server 100 and the cache server 200 through a wired or wireless.

The cache servers 200 according to the embodiment of the present invention form a hierarchical structure, and this layer may be composed of first to nth layers. N is a natural number of 2 or more.

The first layer is the lowest layer, and the closer to the first layer, the lower layer. Also, the n-th layer is a top layer, and the closer to the n-th layer, the higher layer is called.

The lowest level cache server 200 is a server that is closest in transmission time to the client 300, and the highest level cache server 200 is a server that is farthest in transmission time from the client 300. These cache servers 200 each store a copy of the content for providing a streaming service. In particular, the cache server 200 from the lowest to the highest stores the streaming content requested by the client 300 sequentially from the front to the rear.

When the cache servers 200 transmit the streaming content to the client 300, the cache servers 200 start the transmission from the lowest layer, and the servers above the lowest layer transmit sequentially. Accordingly, the client 300 receives the initial content to be quickly reproduced from the nearest cache server 200, thereby reducing the initial buffering time.

As such, cache servers may provide efficient streaming services by hierarchically distributing and storing streaming content. Hereinafter, this distributed storage structure will be described in more detail.

2 is a view for explaining a concept of distributed storage of streaming content according to an embodiment of the present invention. FIG. 2 illustrates a file structure of streaming content 10 stored in a content server (100 of FIG. 1) and streaming content 20 distributed and stored in cache servers (200 of FIG. 1).

The streaming content 10 stored in the content server 100 has a file format consisting of headers 11 and H and content data 12 divided into a plurality of segments a to z.

Meanwhile, the streaming content 20 distributed and stored in the cache servers 200 has a file format composed of hierarchical files consisting of a hierarchical header 21 and hierarchical data 22. The layer files are generated corresponding to the layers of the cache servers 200 described above and are stored in the corresponding cache servers 200.

The layer header 21 classifies the layer according to each cache server 200 and has link information between layer files of streaming content such as itself. The hierarchical data 22 includes at least one segment of the content data 12 divided into a plurality of segments.

In FIG. 2, H1, H2, Hn-1, and Hn represent layer headers 21 of cache servers of the first to nth layers, and a, b, c, d, w, x, y, and z represent streaming data. Represents each segment divided.

Each layer header (H1, H2, Hn-1, Hn) 21 has link information on the location of its upper and lower layer files. For example, the layer header H1 of the first layer file has link information on the location of the second layer file, and the header H2 of the second layer file has link information of the first and third layer files. Further, the layer header of the n-th layer file has link information of the n-th layer and the n-th layer file, and the layer header of the n-th layer file has link information of the n-th layer file.

When the transmission of the streaming content starts, the cache server 200 forms a link between the layer files having the same streaming content through the link information, and allows the cache servers of the plurality of layers to sequentially transmit the next layer file through the link. All.

Therefore, when the first layer cache server starts transmitting to the client 300, the cache servers of the upper layer transmit to the lower layer or start transmitting to the client 300 before the transmission of the first layer cache server is finished.

Hierarchical data 22 includes at least one segment. At this time, the number of segments included in each layer data 22 is distributed according to the number of layers of the cache server 200.

First, it is assumed that specific streaming content has data divided into m segments.

According to an embodiment of the present invention, the segments may be distributed and stored in the same order from the first layer to the nth layer by P (m / n) pieces starting from the segment having the fastest reproduction order. In this case, p is a number smaller than m (p <m).

In addition, according to another embodiment of the present invention, q1 to qn of the same number from the segment having the faster reproduction order may be divided and stored from the first layer to the nth layer. At this time, q1 to qn is smaller than m and must satisfy a large number (m> q1> q2> ...> qn) in the order of q1 to qn.

On the other hand, the first layer file is preferably larger than the size required for the client initial buffering. The client 300 stores a sufficient amount of streaming signals at the beginning of playback to seamlessly service (play) streaming content. That is, in order to provide a streaming service seamlessly from the user's point of view, a streaming signal of a predetermined capacity or more must be stored. Therefore, playback is not started until the streaming signal of a certain capacity or more is stored. For this reason, the size of the layer data of the first layer file stored in the first layer cache server closest to the client in time is more than the data size for initial buffering.

As described above, each content for which a streaming service is provided is divided into hierarchical data having each segment as a basic unit and distributed and stored in various cache servers. At this time, the segment that is played first in time is stored in the lowest layer closest to the client, thereby reducing the initial buffering delay.

On the other hand, the content server 100 or the cache server 200 according to an embodiment of the present invention transmits the above-described streaming content through a streaming signal according to a protocol for streaming service. Then, the client serves as a streaming content player capable of receiving distributed stored streaming content and playing it in real time.

3 is a block diagram showing a schematic configuration of a client according to an embodiment of the present invention.

Referring to FIG. 3, the client 300 includes a communication unit 310, a modem unit 320, a buffer unit 330, a codec unit 340, a playback unit 350, and a control unit 360.

The communication unit 310 transmits a message requesting streaming content to the content server 100 under the control of the control unit 360.

In addition, a streaming signal is received from the content server 100 and the cache server 200. The received streaming signal includes streaming content, which is sequentially received from the first layer file to the nth layer file. The streaming signal also includes video data, audio data and additional data. The streaming signal is continuous in the time domain, and the communication unit 310 continuously receives the streaming signal until the streaming content is finished.

The communication unit 310 may receive a streaming signal according to a wired or wireless protocol.

In the wireless case, the communication unit 310 receives a streaming signal, which is a high frequency (RF) signal, and sequentially converts the received high frequency signal into an intermediate frequency (IF) signal and a base band (BB) signal. In addition, the communication unit 310 converts an analog signal into a digital signal. In the case of transmission, this process is reversed. To this end, the communication unit 310 may include a power amplifier (PA), a low noise amplifier (LNA), a channel filter, a converter (A / D converter, D / A converter), and the like. have.

In the case of a wired line, the communication unit 310 converts and receives a streaming signal, which is a wired analog signal received according to a wired interface, into a digital signal. In addition, at the time of transmission, a wired digital signal is converted into a wireless analog signal and transmitted. To this end, the communication unit 310 may include a converter.

The streaming signal converted into a digital signal is output from the communication unit 310 and input to the modem unit 320.

The modem unit 320 demodulates and outputs a streaming signal, which is an input digital signal. The modem unit 320 modulates the streaming signal in a manner corresponding to a method in which the cache server 200 or the content server 100 modulates the streaming signal, and outputs it to the buffer unit 330.

The buffer unit 330 temporarily stores the input streaming signal. The buffer unit 330 preferably adopts a first-in first-out (FIFO) method in which data first input in time is output first. In addition, the buffer unit 330 may be configured in a stack or queue manner as a storage method of an input streaming signal.

The streaming signal may be a music file composed only of audio data, or a video file composed of audio and video data. Audio and video data also differ in file size used to store one segment. That is, the file size of the video data storing one segment is larger than the audio data. Accordingly, the storage capacity of the buffer unit 330 is preferably a multiple of one segment storage capacity of each of the video data and the audio data.

The buffer unit 330 stores a sufficient amount of streaming signals at the beginning of playback to seamlessly service streaming content. That is, in order to provide a streaming service without interruption from the user's point of view, the buffer unit 330 must store a streaming signal of a predetermined capacity or more. Therefore, playback cannot start until the streaming signal is stored above a certain capacity. According to an embodiment of the present invention, the first layer file is stored in the first layer cache server closest in time to the client to reduce the initial buffering time.

For this reason, at the initial reception of the streaming signal, the buffer unit 330 stores data of a predetermined capacity or more under the control of the controller 360 and then outputs the temporarily stored streaming signal to the codec unit 340. In this case, the data having a predetermined capacity or more is preferably smaller than the capacity of the hierarchical file of the size stored by the first hierarchical cache server.

At this time, the output of the streaming signal of the buffer unit 330 is output according to the data format of the streaming signal. That is, audio data of the streaming signal is output to the audio codec, and video data of the streaming signal is output to the video codec. In addition, when the streaming signal includes additional data, the streaming signal may be output to the corresponding data codec.

The codec unit 340 decodes the input streaming signal and outputs the decoded streaming signal to the reproduction unit 350. At this time, the codec unit 340 decodes the streaming signal according to the data format (stream) of the streaming signal and outputs it to the playback unit 350. To this end, the codec unit 340 may include an audio codec, a video codec, a data codec, and the like. That is, the codec unit 340 decodes the audio data of the streaming signal through the audio codec, and decodes the video data of the streaming signal through the video codec.

The playback unit 350 reproduces the input streaming signals. The playback unit 350 for this includes a display device and an audio device. The display apparatus displays video data among the streaming signals output from the codec unit 340 on the screen. The display device may be formed of a liquid crystal display (LCD). The audio device plays a role of reproducing audio data among the streaming signals output from the codec unit 340. An audio device for this purpose may have a configuration in which audio data, which is a digital signal, is converted into an analog signal, amplified, and reproduced through a speaker.

The controller 360 controls the input / output of the communication unit 310, the modem unit 320, the buffer unit 330, the codec unit 340, and the reproduction unit 250. In particular, the controller 360 controls to store a sufficient amount of the streaming signal in the buffer unit 330 at the initial reception of the streaming signal in order to seamlessly service the streaming content.

Hereinafter, a streaming service providing method performed in a hierarchical distributed storage structure of the cache servers 200 will be described. 4 is a flowchart illustrating a streaming service providing method using a hierarchical distributed storage structure according to an embodiment of the present invention.

In FIG. 4, it is assumed that the cache servers 200 form three hierarchical structures. Accordingly, the cache servers 200 have first to third cache servers 201, 202, and 203 in the first to third layers, respectively, and the first cache server 201 is the lowest cache server. Assume that cache server 203 is a top-level cache server.

In addition, it is assumed that the content server 100 stores copies of its streaming content in the first to third cache servers 201, 202, and 203 as first to third layer files sequentially.

Referring to FIG. 4, the client 300 requests a streaming service to the content server 100 in step S401. This request can be made via wired or wireless.

The content server 100 receiving the streaming service request instructs the first to third cache servers 201, 202, and 203 to transmit streaming content to the client in step S403. Preferably, the transmission instruction is made in the order of the third, second, and first cache servers, and according to the instruction, the first hierarchical file between the first to third cache servers 201, 202, and 203 is performed in step S405. Links connecting the third layer files are formed.

In addition, after the link is formed, the first cache server 201 transmits the first layer file to the client 300 in step S407. Before the transmission of the first layer file is started and the transmission is completed, the second cache server 202 transmits the second layer file to the first cache server 201 in step S409. In addition, before the transmission of the second layer file is started and the transmission is completed, the third cache server 203 transmits the third layer file to the second cache server 202 in step S411.

On the other hand, the first cache server 201, which has started receiving the second layer file, transmits the second layer file to the client 300 successively when the first layer file is completed in step S413. The transmission may be transmitted from the received portion of the second layer file even before the reception of the second layer file is completed so that the streaming service can be transmitted without interruption.

In addition, the second cache server 202 which has started receiving the third layer file transmits the third layer file to the first cache server 201 following the transmission of the second layer file in step S415. The transmission may be transmitted from the received portion of the third layer file even before the reception of the third layer file is completed, so that the streaming service may be transmitted without interruption.

On the other hand, when the transmission of the second layer file is completed in step S417, the first cache server 201 that has started receiving the third layer file transmits the third layer file to the client 300 successively. The transmission may be transmitted from the received portion of the third layer file even before the reception of the third layer file is completed, so that the streaming service may be transmitted without interruption.

At this time, the client 300 sequentially receives the first through the third layer files in step S407, S413, and S417 without interruption, and accordingly plays back the buffering in step S419.

As described above, according to the exemplary embodiment of the present invention, the first layer file is stored in the first layer (lowest layer) cache server having the closest transmission distance to the user and transmitted, thereby reducing the initial buffering delay of the client. You can.

As described above, the present specification and drawings have been described with respect to preferred embodiments of the present invention, although specific terms are used, it is only used in a general sense to easily explain the technical contents of the present invention and to help the understanding of the present invention. It is not intended to limit the scope of the present invention. It is to be understood by those skilled in the art that other modifications based on the technical idea of the present invention are possible in addition to the embodiments disclosed herein.

The present invention can be usefully used for a variety of multimedia streaming services that appear in a variety of forms, such as video content, online education, mass media content such as movies, broadcasts, music, recording and live broadcast, IPTV, including UCC.

1 is a diagram schematically illustrating a hierarchical distributed storage structure of a streaming service providing system according to an exemplary embodiment of the present invention.

2 is a view for explaining a concept of distributed storage of streaming content according to an embodiment of the present invention.

3 is a block diagram showing a schematic configuration of a client according to an embodiment of the present invention.

4 is a flowchart illustrating a streaming service providing method using a hierarchical distributed storage structure according to an embodiment of the present invention.

<Description of main parts of drawing>

100: content server 200: cache server

300: client 310: communication unit

320: modem unit 330: buffer unit

340: codec unit 350: playback unit

360: control unit

Claims (8)

A content server storing streaming content and serving the stored streaming content; The first and last parts of the streaming content are distributed and stored in correspondence with the shortest distance from the closest distance from the first part of the streaming content. A plurality of cache servers sequentially transmitting the last portion; And A client that sequentially receives and buffers the first to last portions of the streaming content and plays the buffered streaming content; Streaming service providing system using a hierarchical distributed storage structure including a. The method according to claim 1, The first part to the last part of the streaming content is composed of a plurality of hierarchical files that divide the streaming content in a playback order, wherein the plurality of hierarchical files include a hierarchical header and hierarchical data, and the hierarchical header corresponds to a replay order. Streaming service providing system using a hierarchical distributed storage structure, characterized in that it has link information of another hierarchical file. The method according to claim 1, When n is a natural number, the plurality of cache servers are configured as cache servers of first to nth layers from a close distance in time to the client, and the first to last parts of the streaming content are n, and the first parts are sequentially. Streaming service providing system using a hierarchical distributed storage structure, characterized in that distributed to the first to n-th layer cache server. The method of claim 3, Streaming content distributed and stored in the first layer cache server streaming service providing system using a hierarchical distributed storage structure, characterized in that the file having a size larger than the initial buffering. A streaming service providing method using a hierarchical distributed storage structure of cache servers, Distributing and storing the first part to the last part of the streaming content in a cache server far from a short distance in time with a client of the cache servers; When a streaming service request is made from a client, sequentially transmitting a first part to a last part of the streaming content by a cache server far from the short distance; The client sequentially receiving and buffering the first to last portions of the streaming content and playing the buffered streaming content; Streaming service providing method using a hierarchical distributed storage structure comprising a. The method according to claim 5, The first part to the last part of the streaming content is composed of a plurality of hierarchical files that divide the streaming content in a playback order, wherein the plurality of hierarchical files include a hierarchical header and hierarchical data, and the hierarchical header corresponds to a replay order. Streaming service providing method using a hierarchical distributed storage structure characterized in that it has link information of another hierarchical file. The method according to claim 5, When n is a natural number, the plurality of cache servers are configured as cache servers of first to nth layers from a close distance with a client in transmission time, and the first to last parts of the streaming content are n and sequentially from the first part. Streaming service providing method using a hierarchical distributed storage structure, characterized in that distributed to the first to n-th layer cache server. The method of claim 7, Streaming content distributed and stored in the first layer cache server has a file size larger than the size required for the initial buffering of the client, the streaming service providing method using a hierarchical distributed storage structure.

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