KR20070099218A - Broadcasting channel grouping apparatus and channel changing method for ip tv - Google Patents

Abstract

An apparatus for grouping broadcasting channels of an IPTV and a channel change method are provided to extract and display a low-quality stream from an STB(Set-Top Box) when a channel change is requested and receive and display a high-quality channel corresponding to a low-quality channel currently displayed when a channel change is no longer requested. A down-streamer(220) encodes a plurality of contents(210) provided from a relay station as low-quality streams. A channel multiplexer(230) groups a plurality of the encoded low-quality streams as one low-quality channel. A channel demultiplexer(270) demultiplexes the low-quality channel received from the Internet(250) and certain high-quality channels.

Description

Broadcasting channel grouping apparatus and channel changing method for IP TV

1 is a view showing a broadcast channel reception method of an IP TV (Internet Protocol TV) according to the prior art.

2 is a diagram of a broadcast channel grouping apparatus of an IP TV according to an embodiment of the present invention;

3 illustrates a down streamer according to an embodiment of the present invention.

4 illustrates a channel multiplexer according to an embodiment of the present invention.

5 illustrates a channel demultiplexer according to an embodiment of the present invention.

6 is a flowchart of changing a channel of an IP TV according to an embodiment of the present invention.

<Explanation of symbols for main parts of the drawings>

200: relay station 210: content

220: downstream streamer unit 230: channel multiplexer

240: streaming server 250: internet

260: STB 270: channel demultiplexer

280: TV

The present invention groups a plurality of broadcast channels into low quality channels and transmits the corresponding channels to the user's STB upon the user's initial channel request to extract and display a low quality stream corresponding to the change request when the user changes the channel. The present invention relates to a broadcast channel grouping apparatus and a channel changing method of an IP TV for receiving and displaying a high quality channel corresponding to a low quality channel being displayed when there is no change request.

In general, IP TVs include IP TVs incorporating Internet modules in existing TV models and STB-type IP TVs connected to a conventional TV by a set top box (hereinafter referred to as STB) that can search the Internet. These IP TVs make it easy to access the Internet using a remote controller or a wired / wireless keyboard in the home.

STB is a kind of signal conversion device installed in a user's home to use digital broadcasting or communication service. In general, STB can be classified into satellite broadcasting, terrestrial broadcasting, cable broadcasting, and IP TV according to service type.

IP TV can use a regular modem, a modem connected to a regular telephone line, and can use xdsl or FTTH.

Multicast is a method of sending the same contents of e-mail, video conferencing, and voice data to two or more other recipients simultaneously on the Internet. In IP multicasting, hosts can join or leave multicast groups, and the Internet Group Management Protocol (IGMP) is included to manage group membership information.

In other words, the multicast transmission method is a transmission technique that prevents waste of network resources due to redundant data transmission and efficiently guarantees real-time collaboration without burdening the place where the information is not needed. do.

IGMP is defined in RFC 1112 as a communication protocol for realizing IP multicast, and is used when a router distributes multicast packets to a personal computer (PC) with multicast communication on a local area network (LAN). Used. In other words, it is a protocol for notifying the router that multicast communication is possible. On the other hand, the router that receives the multicast packet sends the packet to the LAN segment to which the device is connected only when there is a device that has declared reception in IGMP.

Protocol independent multicast (PIM) is a path selection protocol used to send and receive multicast packets when performing multicast on an IP network. It is specified in detail in RFC 2362. There are two types, PIM-DM (dense mode) and PIM-SM (sparse mode). The usage is classified according to the network structure, and multicast can be performed more efficiently than the Distance Vector Multicast Routing Protocol (DVMRP).

1 is a diagram illustrating a broadcast channel reception method of an IP TV according to the prior art.

The broadcast channel reception method of an IP TV according to the prior art includes a relay station, an IP network, and users 1 and 2.

First, branching of broadcasting channels such as terrestrial broadcasting, CATV, and satellite broadcasting from the relay station is performed at the Rendezvous Point (RP) of the IP network (S100).

When the user 1 requests a channel change to the L2 switch using the IGMP protocol while the branching of the broadcast channel is made (S105), the L2 switch transmits an IGMP message to the LHR (Last Hop Router) (S110). The LHR requests the STB 260 of the user 1 to receive the received IGMP information (S115).

User 1 transmits the information corresponding to the request for IGMP information of the LHR to the L2 switch (S120), the L2 switch generates the PIM (protocol independent multicast) (S130) through the LHR (S130) and transmits to the RP (S135).

In the RP receiving the PIM protocol, the corresponding broadcast channel is transmitted to the user 1 (S140), and the user 1 watches the requested channel (S140).

On the other hand, if a channel request occurs on the L2 switch by another user 2 connected to the same IP network (S145), the L2 switch requests and requests an IGMP message of the STB 260 (S150), and L2 corresponding to the request. It is connected to the IGMP message of the switch (S155).

That is, the user 2 may receive the channel requested by the request and connection of the IGMP message (S160).

In the STB of the prior art, a delay factor for processing the corresponding protocols is additionally generated by using a protocol such as IGMP or PIM to receive broadcast channels requested by users 1 and 2 through IP network equipment. As a broadcast channel is received and changed as a request, a delay occurs in a delay of a channel change time and a decoding time of received broadcast channels.

In other words, since every user watching channel and channel change request of each user belonging to the same network is different, each user needs to use a plurality of bandwidths to receive the channel request, and each channel change request receives a broadcast channel from the relay station. As a result, a delay in the network and a delay in the channel decoding time occur.

The present invention has been devised to improve the above-mentioned problem, and a plurality of broadcast channels are grouped into low quality channels and transmitted to the user's STB when the first channel request is made. When a channel change request occurs, the STB extracts and displays a low quality stream. The present invention relates to a broadcast channel grouping apparatus and a channel changing method of an IP TV that receive and display a high quality channel corresponding to a low quality channel being displayed when there is no channel change request.

The objects of the present invention are not limited to the above-mentioned objects, and other objects that are not mentioned will be clearly understood by those skilled in the art from the following description.

In order to achieve the above object, a downstream streamer unit for encoding a plurality of contents provided from an analog or digital signal, a media server, a DVD, etc. of the present invention into a low quality stream, and a channel for grouping a plurality of encoded low quality streams into one channel. A multiplexing unit includes a streaming server unit for providing grouped channels and predetermined high quality channels to the user's STB using an Internet protocol, and a channel demultiplexer for demultiplexing the grouped channels and predetermined high quality channels provided from the streaming server unit. do.

Acquiring a packet identifier corresponding to the channel change in the PMT table when a user requests a channel change of the present invention to achieve the above object, extracting a low quality stream corresponding to the packet identifier from the grouped channels using the packet identifier Displaying on the display unit of the IP TV and requesting and decoding a high quality channel corresponding to a low quality stream when there is no channel change request for a predetermined time.

Specific details of other embodiments are included in the detailed description and the drawings.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various different forms, and only the embodiments make the disclosure of the present invention complete, and the general knowledge in the art to which the present invention belongs. It is provided to fully inform the person having the scope of the invention, which is defined only by the scope of the claims. Like reference numerals refer to like elements throughout.

2 is a diagram illustrating an apparatus for grouping broadcast channels in an IP TV according to an embodiment of the present invention.

The broadcast channel grouping apparatus of the IP TV according to the embodiment of the present invention may include a relay station 200, the Internet 250, an STB 260, and a TV.

The relay station 200 includes the content 210, the downstream streamer 220, the channel multiplexer 230, and the streaming server 240. The broadcast channel of the various contents 210 may be used through the Internet 250 protocol. To the STB 260.

The STB 260 and the TV may be separate or integrated.

The content 210 may include an analog signal, a cable, a terrestrial wave, a digital signal transmitted through a satellite, a media server, a DVD, or the like.

The downstream streamer unit 220 digitizes a plurality of original content 210 provided in various ways, for example, a frame rate of 30 fps, an audio sampling rate of 64 kbps, and a video size of 960 * 540 through a decoder, In order to group the streams, the encoder of the downstream streamer 220 may generate low quality streams including specifications such as a frame rate of 15 fps, an audio sampling rate of 32 kbps, and a video size of 640 * 480. The specification of the original content 210 streams may vary according to user settings.

As such, encoding the streams of the original content 210 into a low quality stream may be a preliminary step for grouping a plurality of low quality streams.

The channel multiplexer 230 may group a plurality of low-quality streams generated by the downstream streamer 220, and according to the multiplexing scheme, frequency division multiplexing (FDM), time division multiplexing (TDM), and code division multiplexing. You can use at least one of the (CDM).

The stream mixer of the channel multiplexer 230 may compress and encode a plurality of encoded streams into one broadcast channel according to a multiplexing method. One low quality broadcast channel grouped as described above may be transmitted to the STB 260 together with one or a predetermined number of high quality broadcast channels through the streaming server 240.

Program specific information (PSI) is required for transmission of grouped low quality broadcast channels, and a program association table (PAT) is a packet with PID = 0, and serves to allocate a transport packet for each program. This packet indicates to which packet the video and audio bit stream constituting the program is loaded. This is called a PMT (Program Map Table).

The channel demultiplexer may display a broadcast channel corresponding to the channel change request on the display unit (not shown) of the TV when the user requests a channel change by using the low quality broadcast channel and the high quality broadcast channel transmitted from the streaming server 240. have.

When the user requests a channel change, a low quality stream corresponding to the change request may be extracted from the grouped low quality broadcast channels.

Based on the PID information of the low quality stream, the PMT can read audio and video PIDs to extract a low quality stream, and demultiplex the corresponding stream to display a low quality broadcast on the display unit of the TV.

If there is no further channel change request by the user, a high quality broadcast channel corresponding to a low quality channel may be received to watch a low quality broadcast channel currently being viewed as a high quality channel.

The STB 260 may include a channel demultiplexer and may further include a storage medium capable of storing streams of low quality grouped into one broadcast channel.

3 is a diagram illustrating a down streamer unit according to an embodiment of the present invention.

The downstream streamer unit 220 according to the embodiment of the present invention may include a decoder 300 and a downstream encoder 310.

First, various original contents, which may include analog signals, cables, terrestrial waves, digital signals transmitted through satellites, media servers, DVDs, and the like, are digitized through the decoder 300 and decoded by the down stream encoder 310. Can encode original content 210.

The encoding of a number of original contents 210 is, for example, a frame rate of 30 fps, an audio sampling rate of 64 kbps, a video size of 960 * 540 streams with a frame rate of 15 fps, an audio sampling rate of 32 kbps, a video size of 640 * 480, etc. It can be generated as a stream of low quality comprising a. The encoding specification of the original content 210 streams may vary according to a user setting, and a plurality of encoded streams may be streamed to the channel multiplexer 230.

4 illustrates a channel multiplexer according to an embodiment of the present invention.

The channel multiplexer 230 according to the embodiment of the present invention may include a plurality of encoded streams 400 and a stream multiplexer 410.

The plurality of streams streamed from the downstream streamer 220 may be multiplexed using at least one of frequency division multiplexing, time division multiplexing, and code division multiplexing according to the multiplexing scheme of the stream multiplexer 410. One low quality broadcast channel transmitted and grouped to the streaming server 240 may be transmitted to the STB 260 along with one or a predetermined number of high quality broadcast channels through the streaming server 240.

PSI is required for transmission of the grouped low quality broadcast channels. PAT is a packet with PID = 0, and serves to allocate a transport packet for each program. This packet indicates to which packet the video and audio bit strings that make up the program are loaded. This is called PMT.

When PID is transmitted by using multiple channels by multiplexing signals of multiple channels with each identifier assigned to packets in the multiplexed transmission flow, each channel signal is first compressed and then packetized. These packets are multiplexed and transmitted in TS form. In this case, the same PID is assigned to a packet corresponding to one channel so as to be distinguished from a packet of another channel. In this way, if packets are distinguished by channel and given a specific ID number, the receiver can demultiplex only packets of a desired channel in the multiplexed TS using the packet ID of the channel.

5 is a diagram illustrating a channel demultiplexer according to an embodiment of the present invention.

The channel demultiplexer 270 according to an embodiment of the present invention may be included in the STB 260 or may be included in the TV 280 including the STB 260.

The STB 260 may include a storage medium 500 capable of storing one low quality channel and one or a predetermined number of high quality channels transmitted from the streaming server 240.

If a user requests a channel change using a remote controller or a wired / wireless keyboard while watching a high quality channel, a low quality stream corresponding to the change request may be extracted from a low quality channel stored in the storage medium 500 of the STB 260. Can be. The extraction of the low quality stream may be performed by reading the video and audio PID corresponding to the PID information according to the change request from the PMT based on the PID information included in the channel.

When the change request low quality stream is extracted, the channel may be demultiplexed using the channel demultiplexer 270. When the demultiplexed low quality channel is displayed for a predetermined time or when the channel selection key is pressed on the remote controller or the wired / wireless keyboard, the high quality channel corresponding to the low quality stream can be requested and decoded.

When the decoding of the high quality channel is completed, the user can watch the high quality channel using the channel as the background of the low quality channel.

6 is a flowchart of channel change according to an embodiment of the present invention.

The channel change according to an embodiment of the present invention may be performed in a state in which the low quality channels grouped in the STB 260 and one or a predetermined number of high quality channels are stored.

A plurality of low quality streams may be generated through the downstream streamer 220 mentioned in FIG. 3, and the generated low quality streams are grouped into a single channel using the channel multiplexer 230. can do.

A plurality of streams grouped into one channel may be transmitted to the streaming server 240 along with one or a predetermined number of high quality channels and transmitted to the STB 260 through the Internet 250. In this case, the transmitted low quality channel includes PID information corresponding to a plurality of streams, and a PMT indicating which packet is included in the information may be stored in the storage medium 500 of the STB 260.

That is, the high quality broadcast channel S600 that the user is currently watching refers to one of the high quality channels that can be stored in the STB 260.

In operation S610, it is determined whether a channel change request is generated by a user while viewing a high quality channel (S600). When a channel change request occurs from a remote controller or a wired / wireless keyboard, the STB 260 may obtain PID information of a low quality channel corresponding to the request and audio and video PID information of the PMT (S620). Based on the channel demultiplexer 270 may extract a low quality stream (S630).

When the stream of low quality is extracted (S630), a low quality channel corresponding to the extracted stream may be displayed on the display unit of the TV (S640).

When the channel change request by the user does not occur while the low quality channel is displayed, the elapse of the channel change waiting time is determined (S650).

The channel change waiting time may be differently set according to the format of the broadcast channel transmitted by the user and may be input in advance.

When a predetermined waiting time elapses or a channel selection input is received from a remote controller or a wired / wireless keyboard, a high quality channel corresponding to a low quality channel is requested, and the received high quality channel may be decoded to be displayed on a TV. (S660).

On the other hand, if a channel selection input is not received by the user and a waiting time that can be input in advance is passed, the channel change request determination step (S610) is fed back and the steps S620 to S640 are repeatedly performed whenever the channel is changed. Can be.

When the reception and decoding of the high quality channel is completed (S670), the channel may be displayed on the display unit of the TV 280 with the background of the low quality channel currently being viewed (S680). These processes may be repeatedly performed whenever a channel change request by the user occurs during the high quality channel viewing (S600).

That is, since the low quality channel and the high quality channel are transmitted at once and stored in the STB (), the time delay in the IP network that may occur during the request and reception of the corresponding channels every time a channel change request is different from the channel requested for each user This reduces the bandwidth waste that can occur.

According to the broadcast channel grouping apparatus and the channel changing method of the IP TV of the present invention as described above has one or more of the following effects.

First, by grouping and transmitting a plurality of broadcast channels, there is an advantage in that a channel request and reception time delay and an allocated bandwidth change in an IP network do not occur when a user requests a channel change.

Second, it is possible to reduce the overall channel change time by reducing the decoding time by displaying the high quality channel in the background with the time delay in the router and the previously displayed low quality channel.

Claims (5)

A down streamer unit for encoding a plurality of contents provided from the relay station into a low quality stream; A channel multiplexer for grouping the encoded plurality of low quality streams into one low quality channel; And And a channel demultiplexer for demultiplexing the low quality channel and the predetermined high quality channels provided through the Internet. A down streamer unit for encoding a plurality of contents provided from the relay station into a low quality stream; A channel multiplexer for grouping the encoded plurality of low quality streams into one low quality channel; And And a channel demultiplexer for demultiplexing the low quality channel and the predetermined high quality channels provided through the Internet. The method of claim 2, When the user requests to change the channel, the low quality channel is extracted using PMT based on the PID of the stream corresponding to the change request in the low quality channel, and displayed on the display unit of the TV. In the case of broadcasting channel grouping apparatus of the IP TV for receiving and decoding the high-quality channel corresponding to the low-quality channel. Acquiring a PID corresponding to the channel change by using a PMT based on PID information of a low quality channel corresponding to the channel when a user requests a channel change; Extracting a low quality channel corresponding to the packet identifier from the channel grouped using the PID and displaying the low quality channel on the display unit of the IP TV; And Receiving and decoding a high quality channel corresponding to the low quality stream when there is no channel change request for a predetermined time. The method of claim 4, wherein When the user requests to change the channel, the low quality stream is extracted through the packet identifier corresponding to the change request and displayed on the display unit of the IP TV. When there is no channel change request for a predetermined time, the high quality corresponding to the low quality stream How to change the broadcast channel of IP TV to receive and display the channel.

Images