KR100981247B1 - System and Tuning Method for Internet Protocol TV Broadcasting Service - Google Patents

Abstract

The present invention relates to an IPTV broadcasting service system, which buffers broadcast data for each channel on a server side, and the IPTV set-top box converts buffered broadcast data of a new channel from an I frame through a unicast method when a channel is switched. Receive and process first. When the delay between the broadcast data received by the unicast method and the broadcast data received by the multicast method is eliminated, the data transmission / reception state of the unicast method is terminated and only the multicast broadcast data is received and processed. According to the present invention, when a user switches channels while watching an IPTV broadcast, the broadcast program of the new channel can be processed quickly.

IPTV, Broadcast, Channel Switching, Buffering, I Frame, Unicast, Multicast

Description

Channel switching method in IP broadcast service system and IP broadcast service system {System and Tuning Method for Internet Protocol TV Broadcasting Service}

The present invention relates to an IPTV broadcasting service system and a channel switching method for the same. In particular, the present invention relates to a quick channel switching when a user switches a channel while using an IPTV broadcasting service.

In recent years, the Internet Protocol TV (IPTV) broadcasting service has begun.

IPTV broadcasting is also called 'Internet multimedia broadcasting', and refers to a broadcasting service provided through an IP (Internet Protocol) network regardless of its name.

IPTV broadcasting service is a combination of communication and broadcasting that enables users to watch through TV receivers by providing various useful information such as video contents or web services as well as live broadcasting through the Internet.

The IPTV broadcasting service system is configured in various forms, and basically includes an IPTV broadcasting server providing a broadcasting service, a VoD server providing a video on demand (VoD), and the like.

The broadcast service for each channel provided by the IPTV broadcast server is made of a multicast method, and the on-demand video service is made of a unicast method because it is serviced according to an individual request of each user.

The multicast method is a transmission method in which broadcast data is directed from one source to several destinations, and the unicast is a transmission method from one source to another destination.

IPTV broadcasting service system is connected to the IPTV set-top box provided in each home through the Internet network. In order to use IPTV broadcasting service in each home, IPTV set-top box and TV receiver should be provided.

Users can use the IPTV service by operating an IPTV set-top box through a remote control as in the conventional broadcast service. The IPTV set-top box may be integrated with the TV receiver or may be configured as an independent device to work with the TV receiver.

Since the IPTV broadcasting service uses the Internet network, it can be easily combined with various services performed on the Internet such as Internet search, movie watching, home shopping, home banking, and online games, and two-way service is possible.

Meanwhile, the IPTV broadcasting service system processes and transmits a video signal among broadcast data of each channel as a bit stream encoded according to a compression scheme such as MPEG-2 or MPEG-4. Each frame is an I frame or a P frame according to the compression ratio. , B frames and the like.

An I frame (Infra Frame) is a coded by performing only processing within the same frame (or field), and serves as a key frame, a P frame (Predicted Frame) is a frame composed based on the information of the previous key frame, Bi-directional frame is a frame composed based on the I / P frame information before and after.

Since the B frame has the largest compression rate, the amount of data is small, but I or P frames must be present when decoding. An I frame has a large amount of data but can be decoded without referring to another frame.

Referring to Figure 1, the process of channel switching in the conventional IPTV set-top box will be described.

The IPTV broadcasting server provides broadcasting services through channels # 1 and # 2, respectively, and the broadcasting services for each channel are performed in a multicast manner. The state where broadcast data consisting of I, B, and P frames is being transmitted for each channel is shown.

Currently, the user is watching the broadcast program of channel # 1 by adjusting the IPTV set-top box to channel # 1. At some point in time, the user switches the channel of the IPTV set-top box to # 2 using the remote control. The IPTV set-top box then starts receiving broadcast data of multicast channel # 2.

As described above, the IPTV set-top box may process a video image only when I frame of broadcast data is received. However, since the B frame is currently received in the multicast channel # 2 at the time T1 at which the channel is switched, the IPTV set-top box has to wait for processing the broadcast data until the time T2 at which the next I frame is received.

Therefore, it is inconvenient that a user can wait for a predetermined time after switching channels so that they can watch a broadcast program of a new channel.

Accordingly, the present invention has been made to solve the above problems, IPTV broadcast service that can reduce the delay time due to channel switching by processing the broadcast data of a new channel more quickly when the channel is switched in the IPTV set-top box Its purpose is to provide a system and channel switching method.

In order to achieve the above object, the IPTV broadcasting service system according to the present invention is an IPTV broadcasting server for transmitting broadcast data of each channel in a multicast manner through an internet network, and broadcasting of each channel transmitted by the IPTV broadcasting server. A buffering server that buffers data and transmits an I frame when a broadcast data of a specific channel is requested, and an IPTV set-top box that receives and processes broadcast data through the Internet network.

In this case, the IPTV set-top box is a pre-processing unit for terminating the old channel connection to the IPTV broadcast server when the channel is switched and accessing the buffering server to receive the buffered broadcast data of the new channel from the I frame in a unicast manner; And a post-processing unit for performing new channel access to the IPTV broadcasting server and terminating the broadcast data transmission by the unicast method performed by the buffering server.

The post processing unit may be configured to terminate broadcast data transmission by a unicast method performed by the buffering server when a delay between the broadcast data received from the buffering server and the broadcast data received from the IPTV broadcast server is eliminated. have.

The channel switching method in the IPTV broadcasting service system according to the present invention comprises the steps of: buffering the broadcast data of each channel transmitted by the IPTV broadcast server in a multicast manner; When the IPTV set-top box connected to one channel (old channel) of the IPTV broadcasting server is switched to another channel (new channel), the IPTV set-top box terminates the old channel connection of the IPTV broadcasting server and the new channel of the buffering server. Accessing a channel; Transmitting, by the buffering server, the broadcast data of the new channel from the I frame to the IPTV set-top box in a unicast manner, and processing and outputting the broadcast data received from the buffering server by the IPTV set-top box; The IPTV set-top box accessing a new channel of the IPTV broadcasting server and terminating the connection with the buffering server (channel switching completion step); And processing and outputting, by the IPTV set-top box, broadcast data received through a new channel of the IPTV broadcast server.

In the channel switching completion step, the IPTV set-top box may be configured to terminate the connection with the buffering server when the delay between the broadcast data received from the buffering server and the broadcast data received from the IPTV broadcast server is eliminated. .

The channel switching completion step may include: transmitting, by the buffering server, a multicast switching message to the IPTV set-top box; Accessing, by the IPTV set-top box, a new channel of the IPTV broadcasting server according to the multicast switching message; Checking, by the IPTV set-top box, whether an overlap has occurred between broadcast data received from the buffering server and broadcast data received from the IPTV broadcast server; Requesting, by the IPTV set-top box, to stop transmission of broadcast data to the buffering server if an overlap occurs; And ending, by the buffering server, broadcasting data transmission for the IPTV set-top box according to the request.

According to the present invention, when a user using an IPTV broadcasting service switches a channel while watching a broadcast program of a specific channel, the IPTV set-top box may immediately process and output a video image of the new channel.

As a result, delay time due to channel switching can be reduced, thereby facilitating users' convenience of using the IPTV broadcasting service.

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

Referring to FIG. 2, the IPTV broadcasting service system 20 according to the present invention is an IPTV broadcasting server 21, a buffering server 22, and an IPTV set-top box 23 provided in each user's home as server-side components. It is made, including.

The IPTV set-top box 23 is connected to the TV receiver 24, and the audio / video signal processed by the IPTV set-top box 23 is output through the screen and the speaker of the TV receiver 24. The IPTV set-top box 23 may be integrated with the TV receiver or may be configured as an independent device to work with the TV receiver.

Users can watch a broadcast program of a desired channel while switching channels using a remote controller as in the conventional broadcast service.

The IPTV broadcast server 21 transmits broadcast data for each channel in a multicast manner through the Internet network 15.

The video data for each channel is compressed and encoded into I frames, P frames, and B frames, and then formed into a packetized elementary stream (PES). In general, a GOP including a small number of P frames and a large number of B frames around an I frame Group Of Pictures).

Audio data is also compressed and encoded into an element stream (ES) and then formed into a PES.

The video PES and the audio PES are multiplexed, converted into a transport stream (TS), and then transmitted through the Internet network 15.

The buffering server 22 buffers broadcast data of each channel transmitted by the IPTV broadcast server 21.

The buffering server 22 buffers the broadcast data of each channel to quickly deliver the I-frame of the new channel when the channel is switched in the IPTV set-top box 23. The buffering server 22 is an IPTV set-top box ( According to the request of 23), the broadcast data of the channel is transmitted from the I frame in the unicast method.

Meanwhile, the IPTV set-top box 23 basically connects to the Internet network 15 through the router 16, processes broadcast data received from the Internet network 15, and outputs the broadcast data to the TV receiver 24. do.

Looking at the basic operation of the IPTV set-top box 23, as the user sets the channel by operating the remote control to connect to the current channel between the router (Join), or terminates the connection with the previous channel ( Leave). These 'Join' and 'Leave' operations are performed according to the Internet Group Management Protocol (IGMP). The IGMP 'Join' message plays a role of activating the traffic port of the channel, and the IGMP 'Leave' message plays a role of deactivating the traffic port of the channel.

The IPTV set-top box 23 stores the audio / video data of the corresponding channel received through the router 16 in a buffer and decodes them in order. In this process, the IPTV set-top box 23 performs various operations such as DRM (Digital Rights Management) processing and A / V PID parsing.

The IPTV set-top box 23 may be configured to have various functions necessary to use the IPTV broadcasting service in various ways in addition to the basic operation.

In particular, the IPTV set-top box 23 according to the present invention includes a preprocessor 23-1 and a post processor 23-2 with respect to the channel switching function.

When the channel is switched, the preprocessor 23-1 terminates the old channel connection to the IPTV broadcasting server 21, connects to the buffering server 22, and receives the new channel broadcast data from the I frame in a unicast manner. .

The post processing unit 23-2 performs a new channel (multicast channel) connection to the IPTV broadcasting server 22 and terminates transmission and reception of broadcast data by the unicast method between the buffering server 22 and the server. To perform.

Referring to FIG. 3, the process of channel switching in the IPTV set-top box 23 according to the present invention will be described as a whole.

First, while watching a broadcast program of channel # 1, the user switches the channel of the IPTV set-top box 23 to # 2 (S31).

Then, the IPTV set-top box 23 terminates the old channel connection, accesses the channel # 2 of the buffering server 22, receives broadcast data of channel # 2 from the I frame, and processes the broadcast data of channel # 2 quickly. (S32).

At this time, the data transmission between the IPTV set-top box 23 and the buffering server 22 is made in a unicast manner.

The IPTV set-top box 23 connects to the multicast channel # 2 and terminates the unicast connection according to the reception state of the broadcast data through the multicast channel (S33). Thereafter, broadcast data is received only through the multicast channel # 2.

In principle, it is necessary to receive broadcast data through a multicast channel because unicast data transmission has a heavy network load.

A detailed example of an operation process of the preprocessor 23-1 will be described with reference to FIG. 4. In this case, it is assumed that the IPTV set-top box 23 is switched from channel # 1 to channel # 2.

When the channel is switched, the preprocessor 23-1 first terminates the connection of the multicast broadcast channel # 1, and connects to the channel # 2 of the buffering server 22.

The broadcast data for channel # 2 is received from the buffering server 22 from the I frame, and the broadcast data is transmitted and received with the buffering server 22 in a unicast manner. Transmission of broadcast data performed by the buffering server 22 in a unicast manner is processed to be faster than in the case of multicast broadcasting. This is to eliminate the delay between the two broadcast data.

Now, the IPTV set-top box 23 decodes broadcast data of channel # 2 received in a unicast manner and outputs it to the TV receiver 24.

A detailed example of an operation process of the post processor 23-2 will be described with reference to FIG. 5.

First, the buffering server 22 transmitting the broadcast data of channel # 2 in the unicast manner according to the request of the preprocessor 23-1 delays the broadcast data transmitted by the unicast scheme and the multicast broadcast data. When this is resolved, the IPTV set-top box 23 transmits a multicast conversion message.

The post processor 23-2 accesses the multicast channel # 2 through the IGMP 'Join' message between the router 16 and the multicast switch message transmitted from the buffering server 22.

The post processor 23-2 checks whether an overlap occurs between broadcast data received in a unicast manner and broadcast data received in a multicast channel. That is, if an overlap occurs, the delay between the broadcast data received through the multicast channel and the broadcast data received in the unicast method can be regarded as being eliminated.

Therefore, if this condition is satisfied, the post-processing unit 23-2 requests the buffering server 22 to stop transmission of the broadcast data by the unicast method, and the buffering server 22 according to the request for the corresponding IPTV set-top box ( End unicast transmission to 23).

Now, the IPTV set-top box 23 is in a state of receiving broadcast data only through the multicast channel # 2, and unicast data transmission, which unnecessarily increases traffic to the network, is stopped.

As described above, the delay due to the channel switching can be reduced by immediately receiving broadcast data of the new channel from the I-frame from the buffering server 22 through the unicast method and immediately processing the channel. In addition, when the reception of broadcast data through the multicast channel is normalized, the transmission of the unicast scheme is immediately stopped, and thus does not significantly affect the network load.

Referring to FIG. 6, an embodiment of a channel switching method in an IPTV broadcasting service system according to the present invention will be described.

First, each channel data transmitted by the IPTV broadcasting server in a multicast manner is buffered through the buffering server (S61).

The buffering server buffers the broadcast data of each channel to quickly deliver the I frame of the new channel when the channel is switched in the IPTV set-top box. The buffering server broadcasts the channel at the request of the IPTV set-top box. Data is transmitted from I frame by unicast method.

Meanwhile, the IPTV set-top box connected to the multicast channel # 1 of the IPTV broadcasting server is switched to the new channel # 2 according to the user's instruction (S62).

Then, the IPTV set-top box terminates the connection to the multicast channel # 1 of the IPTV broadcasting server and accesses the channel # 2 of the buffering server (S63).

The buffering server transmits the buffered broadcast data of channel # 2 to the IPTV set-top box in an unicast manner from the I frame, and the IPTV set-top box processes the broadcast data of channel # 2 received from the buffering server and outputs it through the TV receiver. (S64).

Then, at a specific time point, the IPTV set-top box accesses the multicast channel # 2 and terminates the connection to the buffering server to receive and process broadcast data only through the multicast channel # 2 (S65).

The time point at which the IPTV set-top box accesses the multicast channel and the end time of the unicast connection in step S65 may be variously configured as necessary.

One example is that the delay between the broadcast data received in the unicast manner from the buffering server and the broadcast data received in the multicast manner from the IPTV broadcast server is made in relation to the time point at which the delay is eliminated.

An exemplary embodiment of a process of performing step S65 will be described with reference to FIG. 7.

First, when it is determined that the delay between the broadcast data transmitted by the unicast method and the broadcast data of the multicast channel # 2 is eliminated, the buffering server transmits a multicast switching message to the IPTV set-top box (S71).

After receiving the multicast switching message from the buffering server in step S71, the IPTV set-top box accesses the multicast channel # 2 of the IPTV broadcasting server (S72).

The IPTV set-top box compares the broadcast data received from the buffering server with the broadcast data received through the multicast channel # 2 and checks whether an overlap has occurred between the broadcast data (S73).

Checking whether or not the overlap occurs in step S73 is because the delay between the multicast broadcast data and the unicast broadcast data can be regarded as being eliminated when the overlap occurs.

If the overlap in the result of the check in step S73 occurs (S74), the IPTV set-top box requests to stop the transmission of broadcast data by the unicast method to the buffering server, the buffering server according to the request broadcast data for the corresponding IPTV set-top box By stopping transmission, the unicast traffic is removed from the network (S75).

Referring to FIG. 8, a process of switching channels in an IPTV set-top box according to the present invention will be described.

The IPTV broadcasting server provides broadcasting services of channels # 1 and # 2 in a multicast manner (81, 82), and a buffering server (BS) buffers broadcasting data of channel # 2 (83). . In the drawing, 'I, B, B, P, B, B, P, B, B, P, I, B, B, P' and the like indicate each frame of the video signal.

'Video Display' 85 indicates a display (eg, TV receiver) on which an image processed by the IPTV set-top box is output.

The user is currently watching channel # 1, and at some point A, the channel of the IPTV set-top box is switched to # 2 using the remote control.

Then, the IPTV set-top box terminates the connection of the multicast channel # 1 (IGMP Leave Ch. # 1) and unicasts the channel # 2 of the buffering server. The buffering server transmits the buffered broadcast data of channel # 2 from I frame to a certain amount (Data1) at a high speed, thereby eliminating a delay with the broadcast data of multicast channel # 2 (each 'B' in each case). The frame position is shown to be the same).

On the other hand, the IPTV set-top box that receives the broadcast data (Data1) starting from the I frame from the buffering server at the time point B can process the broadcast data of channel # 2 immediately at the time point B, and starts to be output to the TV receiver screen. In this case, delay factors such as DRM, buffering for decoding, and A / V PID parsing in IPTV set-top boxes are not considered.

Since the buffering server transmits the broadcast data Data1, the broadcast data of the multicast channel # 2 and the delay factor have been eliminated. Therefore, the buffering server sends a multicast switching message to the IPTV set-top box at time C, and the broadcast data (Data2) thereafter. Transmits at the same rate as the multicast rate.

The IPTV set-top box connects to multicast channel # 2 at time C according to the multicast switching message from the buffering server (IGMP Join Ch. # 2).

In addition, it is determined whether an overlap occurs between broadcast data received through the multicast channel # 2 and broadcast data received in a unicast manner from the buffering server.

If an overlap occurs, all necessary broadcast data is being received through the multicast channel (E), and therefore, at the point of time D, a request is made to stop the unicast transmission to the buffering server, and the buffering server according to the request according to the IPTV set-top box. Ends broadcast data transmission to the network.

IPTV set-top boxes now receive and process broadcast data only through multicast channel # 2.

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 for explaining that a delay occurs in the conventional channel switching,

2 is an embodiment of an IPTV broadcasting service system according to the present invention;

3 is an overview of a process of switching channels by an IPTV set-top box,

4 is an example of an operation process of a preprocessor;

5 is an example of an operation process of a post processing unit;

6 and 7 illustrate embodiments of a channel switching method in an IPTV broadcasting service system according to the present invention;

8 is a diagram schematically showing an overall process of channel switching according to the present invention.

DESCRIPTION OF THE REFERENCE NUMERALS

15: Internet Network 16: Router

20: IPTV broadcasting service system 21: IPTV broadcasting server

22: Buffering Server 23: IPTV Set Top Box

23-1: pre-processing unit 23-2: post-processing unit

24: TV receiver

Claims (5)

IPTV broadcasting server that transmits broadcasting data of each channel by multicast method through internet network, and buffers broadcasting data of each channel transmitted by the IPTV broadcasting server and transmits from I frame when broadcasting data of a specific channel is requested. And a buffering server and an IPTV set-top box for receiving and processing broadcast data through the Internet network. The IPTV set top box A preprocessing unit for terminating the old channel connection to the IPTV broadcasting server and accessing the buffering server to receive the buffered broadcast data of the new channel from the I frame in a unicast manner when the channel is switched; And A post-processing unit for performing new channel access to the IPTV broadcasting server and terminating broadcast data transmission by a unicast method performed by the buffering server, The post processing unit accesses a new channel to the IPTV broadcasting server according to a multicast switching message transmitted by the buffering server, and buffers the delay when the delay between the buffering server and the broadcast data received from the IPTV broadcasting server is eliminated. IPTV broadcasting service system characterized in that the server terminates the transmission of broadcast data by the unicast method. delete Buffering the broadcast data of each channel transmitted by the IPTV broadcast server in a multicast manner; When the IPTV set-top box connected to one channel (old channel) of the IPTV broadcasting server is switched to another channel (new channel), the IPTV set-top box terminates the old channel connection of the IPTV broadcasting server and the new channel of the buffering server. Accessing a channel; Transmitting, by the buffering server, the broadcast data of the new channel from the I frame to the IPTV set-top box in a unicast manner, and processing and outputting the broadcast data received from the buffering server by the IPTV set-top box; The IPTV set-top box accessing a new channel of the IPTV broadcasting server and terminating the connection with the buffering server (channel switching completion step); And And processing, by the IPTV set-top box, broadcasting data received through a new channel of the IPTV broadcasting server, and outputting the broadcast data. The method of claim 3, wherein In the channel switching completion step, the IPTV set-top box is configured to terminate the connection with the buffering server when the delay between the broadcast data received from the buffering server and the broadcast data received from the IPTV broadcast server is eliminated. A channel switching method in an IPTV broadcasting service system. The method of claim 3, wherein the channel switching completion step Sending, by the buffering server, a multicast switch message to the IPTV set-top box; Accessing, by the IPTV set-top box, a new channel of the IPTV broadcasting server according to the multicast switching message; Checking, by the IPTV set-top box, whether an overlap has occurred between broadcast data received from the buffering server and broadcast data received from the IPTV broadcast server; Requesting, by the IPTV set-top box, to stop transmission of broadcast data to the buffering server if an overlap occurs; And And the buffering server is configured to terminate the transmission of broadcast data for the IPTV set-top box according to the request.

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