KR100979311B1 - Method of Handling Buffering Process for VoD Service, and IPTV Settop Box with Adaptive Buffering Function - Google Patents

Abstract

The present invention allows a client using a Video on Demand (VoD) service to adaptively adjust the size of a buffer to temporarily store audio / video data according to network conditions. In addition, the VoD server adjusts the stream transmission rank according to the buffer status of each client. Accordingly, even in a 'best-effort' network where QoS (Quality of Service) is not guaranteed, it is possible to provide a high quality streaming service while minimizing time delay. The buffer size is adaptively adjusted according to network conditions, allowing seamless streaming service without a hard disk drive and more efficient use of memory resources.

Video On Demand, VoD, Buffering, Adaptive, Streaming, Internet, IPTV

Description

Method of Handling Buffering Process for VoD Service, and IPTV Settop Box with Adaptive Buffering Function}

The present invention relates to a buffering processing method for an VoD service and an IPTV set-top box having an adaptive buffering function. In particular, the present invention relates to a high-definition streaming service even through a 'best-effort' network that does not guarantee a quality of service (QoS) such as the Internet. It is to be able to provide efficiently.

Unlike the conventional broadcasting service, which was able to watch broadcast programs unilaterally transmitted by the current broadcasting station, an interactive broadcasting service is provided to allow a user to watch desired content anytime and anywhere.

An example of such an interactive service is a Video on Demand (VoD) service that allows a user to watch desired content anytime, anywhere. Recently, IPTV broadcasting service has been started.

VoD service and IPTV service are provided through the internet network. In general, the internet network is a 'best-effort' network that does not guarantee quality of service (QoS).

Here, a network that stably provides a bandwidth having a constant level of CBR (Constant Bit Rate) in terms of delay, loss, and jitter is called a QoS (Quality of Service) guarantee network. define.

In addition, on the average, a network that provides more than a certain level of bandwidth, but may cause an unstable delay, loss, or jitter depending on network conditions, is defined as a 'best-effort network'.

Currently, most high-speed Internet services provided by most Internet Service Providers (ISPs) are provided through 'Best-Effort' networks, and a network constructed separately, such as a real-time broadcasting network, can be called a QoS guarantee network.

On the other hand, in a VoD service system having a network-connected server-client structure, high-definition audio / video (hereinafter, referred to as AV) content is provided to a user using two methods as follows.

First, the streaming method is a method of processing AV content received through the network immediately without any time delay, and the 'Download & Play' (D & P) method is a hard disk drive (HDD) : Hard Disk Drive) is a method to store data over a certain amount and process the data stored in the hard disk drive for viewing.

The streaming technique uses the User Datagram Protocol (UDP) based transport protocol, which eliminates the need to store AV content on the hard disk drive and allows for immediate viewing without time delay, while avoiding packet loss, delay, and jitter on the network. Strict levels of QoS must be guaranteed. This means a lot of equipment investment on the network.

The D & P technique has the advantage of not guaranteeing the strict network QoS as required by the streaming technique, but it uses a transmission protocol based on TCP (Transmission Control Protocol) to store a certain amount of AV content on the hard disk drive before Each client must be equipped with a large hard disk drive because it must process content stored in the server. In addition, in the case of using a trick mode such as fast forward, the AV data is not yet stored in the hard disk drive.

FIG. 1 illustrates an example of a streaming scheme, in which the AV output is seamlessly performed in the QoS guarantee network (a), but in the 'Best-Effort' network, the AV output is cut off in the middle (b). . That is, in the 'Best-Effort' network, 8Mbps bandwidth data transmission is guaranteed on average, but there may be instant packet delay or jitter. As shown in FIG. It can be.

FIG. 2 illustrates a viewing state. In the case of using the streaming technique as shown in FIG. 2A, the output is started within a very short time after the viewer gives a playback command.

However, in the case of using the D & P technique as shown in FIG. 2B, it takes a long time to download and store a certain amount of AV content on the hard disk drive. This delay is very long compared to when using the streaming technique. This is the same problem that occurs even when the viewer tries to watch from the middle of the content.

As described above, the VoD service based on the streaming technique has the advantage that the user can quickly view the high-definition AV content, while the disadvantage is that a lot of facility investment must be made to guarantee the QoS on the network. In VoD service, even if the network's QoS is not guaranteed, high-definition AV contents can be viewed without interruption, but each client has a large capacity hard disk drive and a delay in viewing.

Accordingly, the present invention has been made to solve the above problems, the advantages of the streaming technique that allows the user to quickly watch the AV content, and to ensure that the AV content without interruption even in a situation where the network QoS is not guaranteed Its purpose is to provide a buffering processing method for the VoD service and an IPTV set-top box with adaptive buffering function by combining the advantages of the 'Download & Play' technique.

In order to achieve the above object, the buffering method for a VoD service according to the present invention, the client periodically checks the status of the Internet network; And varying a size of a buffer for temporarily storing audio / video data according to the identified state of the internet network.

At this time, the size of the buffer may be configured to decrease when the state of the Internet network is good and increase when the state of the Internet network is bad.

The VoD server providing the VoD service to the client may be configured to check the amount of audio / video data stored in the buffer of each client and transmit more streams to the client having a smaller amount of buffered audio / video data. Can be.

On the other hand, IPTV set-top box having an adaptive buffering function according to the present invention, network status check unit for periodically checking the status of the Internet network; A buffer size adjusting unit for adjusting a size of a buffer for temporarily storing audio / video data according to a result of checking the network state checking unit; A buffering processor configured to buffer audio / video data of a broadcast signal received through the Internet network in the buffer; And a decoder that decodes the audio / video data in the buffer.

The buffer size adjusting unit may be configured to reduce the size of the buffer when the state of the Internet network is good, and to increase the size of the buffer when the state of the Internet network is bad.

According to the present invention, since the streaming technique is basically used, the user can quickly watch the desired AV content.

Clients or IPTV set-top boxes that use VoD services can adjust the buffer size according to network conditions, allowing users to watch high-definition AV content seamlessly even in a network environment where QoS is not guaranteed. This removes the burden of network facilities that require strict levels of QoS and eliminates the need for mass storage media such as hard disk drives.

In this way, it is possible to effectively combine the advantages of streaming and D & P techniques, and economically manage limited resources.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Referring to FIG. 3, each of the clients 33-1 to 33-n uses a video on demand (VoD) service provided by the VoD server 31 through the 'best-effort network' 32. It is a terminal. Hereinafter, the Internet network will be described as an example of the 'best-effort network' 32.

Each client 33-1 to 33-n may be configured in various forms such as a personal computer (PC) or an IPTV set-top box. When each client 33-1 to 33-n requests content from the VoD server 31, the VoD server 31 transmits the requested content in a streaming manner.

Referring to FIG. 4, each of the clients 33-1 to 33-n temporarily stores AV data included in a stream received from the VoD server 31 in a buffer (S41), and stores the AV data temporarily stored in the buffer. Decoded in order and delivered to the display screen and the speaker (S42). If the client is an IPTV set-top box, the display screen and the speaker will be a TV receiver, and the user will watch the content through the TV receiver.

Referring to FIG. 5, the buffering processing method for the VoD service according to the present invention is a process performed in each of the clients 33-1 to 33-n, and the size of the buffer is variably operated according to the state of the Internet network.

First, the client periodically checks the state of the Internet network (S51, S52).

In step S52, the method of allowing the client to check the status of the Internet network may be variously configured as necessary. One example is to configure a network to check the network status by sending and receiving a packet for checking the status of the Internet network 32 with the VoD server 31.

When the state of the Internet network is confirmed in step S52, the client adjusts the size of the buffer to buffer the AV data according to the confirmed state of the Internet network (S53).

If the status of the Internet network is good, there is no need for a lot of buffering, if the status of the Internet network is poor, a lot of buffering is possible to watch seamlessly. Therefore, in step S53, as the state of the Internet network is good, the size of the buffer can be reduced, and as the state of the Internet network is poor, the size of the buffer can be increased.

Referring to FIG. 6, another embodiment of a buffering processing method for a VoD service according to the present invention will be described.

This embodiment relates to a process performed in the VoD server 31, and each of the clients 33-1 to 33-n operates while varying the size of the buffer according to the state of the Internet network as described above.

Meanwhile, the VoD server 31 adjusts the priority of the stream to be transmitted to each client 33-1 to 33-n according to the amount of AV data stored in the buffer of each client 33-1 to 33-n. It can be configured to.

That is, if a client starts playing a particular content for the first time or starts playing again from an intermediate point, or if there is a small amount of AV data in the buffer due to poor Internet conditions, the client may have more streams. Can be processed to send.

At this time, each of the clients 33-1 to 33-n transmits information about the amount of AV data stored in its buffer to the VoD server 31, and the VoD server 31 sends the stream scheduler 31-1. ) To handle sending more streams to less buffered clients.

In the illustrated example, reference numeral 66-1 denotes the buffer state of the client # 1, and the AV data is filled by the size TH1 of the buffer, which is an appropriate level according to the current state of the Internet network.

Reference sign 66-2 indicates the buffer state of the client # 2, which indicates that the AV data is far below the proper buffer size TH2, which means that the content may have started to be played for the first time or again from the middle point. Or when the state of the Internet network becomes poor.

Code 66-3 indicates the buffer state of client # 3, and the AV data is filled in the appropriate buffer size TH3, and indicates that the client has increased the size of the buffer because the Internet network is in poor condition. have.

On the other hand, the stream scheduler 31-1 controlling the stream transmission in the VoD server 31 controls the stream transmission status according to the buffer status of each client as described above.

The stream scheduler 31-1 streams the stream 61 to be transmitted to the client # 1, the stream 62 to be transmitted to the client # 2, and the stream 63 to be transmitted to the client # 3 to the Internet network 32 according to priority. (64) is output (64).

Therefore, in the above example, the stream scheduler 31-1 processes to transmit more streams to the client # 2 among the clients # 1 to # 3.

That is, each of the clients 33-1 to 33-n has a larger amount of VoD server 31 than the other clients when the amount of AV data to be played for a predetermined threshold time is not buffered. This results in the same as requesting to send the AV data, and the VoD server 31 uses the stream scheduler 31-1 based on the amount of AV data buffered in each of the clients 33-1 to 33-n. By adjusting, the amount of streaming can be adjusted for each client.

Referring to FIG. 7, each IPTV set-top box 73 accesses an IPTV server 71 through an internet network 72 to use an IPTV broadcast service.

The Internet Protocol TV (IPTV) service is a service that combines communication and broadcasting to provide broadcasting, video content, and various useful information through the Internet network 72 so that it can be viewed through a TV receiver.

The IPTV server 71 providing the IPTV service is connected to the IPTV set-top box 73 provided in each home through the Internet network 72.

As such, in order to use the IPTV service in each home, the IPTV set-top box 73 and the TV receiver 74 should be provided.

IPTV service users can use the IPTV service by operating the IPTV set-top box 73 through a remote control as in the conventional broadcast service. Since the IPTV service uses the Internet network 72, various services performed on the Internet, such as Internet search, watching movies, home shopping, home banking, and online games, can be easily combined and easily combined with interactive services.

The IPTV set-top box 73 is configured as an integral or independent device with the television receiver 74 to work with the television receiver.

8, an embodiment of an IPTV set-top box 73 having an adaptive buffering function according to the present invention will be described.

The network status checking unit 81 periodically checks the status of the Internet network 72.

How the network status checking unit 81 checks the status of the Internet network 72 may be variously configured as necessary. An example of this is configured to check the status of the current Internet network 72 while sending and receiving packets for checking the status of the Internet network 72 with the VoD server 71.

The buffer size adjusting unit 82 adjusts the size of the buffer 85 to temporarily store the AV data according to the result of the network status checking unit 81.

At this time, the buffer size adjusting unit 82 decreases the size of the buffer 85 when the state of the Internet network 72 is good, and increases the size of the buffer 85 when the state of the Internet network 72 is bad. It can be configured to. In other words, if the current state of the Internet network 72 is good, since the packets sent from the IPTV server 71 according to the streaming method arrive without difficulty, there is no need for much buffering. However, if the state of the Internet network 72 is poor, since the packets sent from the IPTV server 71 according to the streaming method may not reach normally, a lot of buffering is performed.

The buffering processor 83 buffers the AV data of the broadcast signal received through the Internet network 72 in the buffer 85.

The decoder 84 decodes the AV data temporarily stored in the buffer 85 in order and transfers the AV data to the TV receiver 74.

As described above, the IPTV set-top box 73 according to the present invention is in a situation where the QoS of the Internet network 72 is not guaranteed, and if only a certain amount of bandwidth is guaranteed on average, even if it is not equipped with a hard disk drive (HDD), a high capacity without interruption is achieved. Allows you to watch AV content.

In other words, rather than storing a large amount of AV content in the hard disk drive, the size of the buffer can be changed according to the state of the Internet network 72 to achieve memory efficiency and to maintain a seamless playback state.

Compared to the D & P method, only a very short delay occurs and high quality HD AV contents can be provided even in a network shaking condition.

The above-described embodiments are intended to help the understanding of the present invention, and the present invention is not limited to the above-described embodiments and can be variously modified and implemented by those skilled in the art without departing from the spirit of the present invention. to be.

1 is an example in which disconnection occurs in a 'best-effort' network,

2 is an overview of the time delay occurs when applying the D & P technology,

3 is an overview of an on-demand video system;

4 is an overview of a process of processing a stream in a client,

5 is an embodiment of a buffering processing method for a VoD service of the present invention;

6 is another embodiment of a buffering method for a VoD service of the present invention;

7 is an overview of an IPTV service system;

8 is an embodiment of an IPTV set-top box having an adaptive buffering function according to the present invention.

DESCRIPTION OF THE REFERENCE NUMERALS

31: VoD server 32, 72: Internet network

33-1 to 33-n: Client 31-1: Stream Scheduler

71: IPTV Server 73: IPTV Set Top Box

74: TV receiver 81: network status check unit

82: buffer size adjusting unit 83: buffering processing unit

84: decoder 85: buffer

Claims (5)

In a method for a client using a video on demand (VOD) service buffers audio / video data of video content received from a VoD server through an Internet network. Periodically checking the state of the Internet network; And Varying a size of a buffer for temporarily storing the audio / video data according to the identified state of the internet network; And the size of the buffer decreases when the state of the Internet network is good and increases when the state of the Internet network is bad. delete The method of claim 1, The VoD server checks the amount of audio / video data stored in the buffer of each client, and transmits more streams to the client having a smaller amount of buffered audio / video data. How to handle buffering. In the IPTV set-top box that processes the broadcast signal received from the IPTV server through the Internet network and delivers it to the TV receiver, A network state checking unit periodically checking a state of the internet network; A buffer size adjusting unit for adjusting a size of a buffer for temporarily storing audio / video data according to a result of checking the network state checking unit; A buffering processor configured to buffer audio / video data of a broadcast signal received through the Internet network in the buffer; And A decoder for decoding audio / video data in the buffer, The buffer size adjusting unit is configured to reduce the size of the buffer when the state of the Internet network is good, and to increase the size of the buffer when the state of the Internet network is poor. Having an IPTV set-top box. delete

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