KR20080113903A - Method for processing picture frame on iptv and system thereof - Google Patents

Abstract

A method and a system for processing an image frame are provided to reduce a channel changing time occurring when a channel is changed in an IPTV, thereby improving image service quality. A selected channel and broadcasting information of an adjacent channel with regard to the selected channel are received(S6). Broadcasting information of the selected channel is reproduced and outputted(S10). An I frame of an image frame among the broadcasting information of the adjacent channel is stored(S22). A stored I frame and a P frame of an image frame received from the adjacent channel are decoded to output image information with regard to the adjacent channel.

Description

Method and system for processing image frame in IPTV {METHOD FOR PROCESSING PICTURE FRAME ON IPTV AND SYSTEM THEREOF}

1 is a diagram for explaining a video frame decoding procedure in a conventional IPTV video frame processing system.

2 is a block diagram of a video frame processing system in IPTV according to an embodiment of the present invention;

3 is a header diagram of a broadcast request message according to an embodiment of the present invention;

4 is a flowchart for explaining a video frame processing method in IPTV according to an embodiment of the present invention;

5 is an exemplary channel multicast group address table for each channel according to an embodiment of the present invention.

6 and 7 are exemplary channel changes for explaining a video frame processing method in IPTV according to an embodiment of the present invention.

8 is a view for explaining a video frame decoding sequence in the IPTV video frame processing system according to an embodiment of the present invention.

The present invention relates to a method and a system for processing an image frame in an IPTV, and more particularly, to a technique for reducing a channel moving time in an IPTV (Internet Protocol TeleVision).

Recently, with the spread of personal computers and high-speed modems, multimedia data can be transmitted, resulting in the convergence of broadcasting and communication.

In the Internet broadcasting, an internet broadcasting server configured on the web provides a plurality of channels, and a user terminal (IPTV) receives a broadcasting signal for a specific channel from the internet broadcasting server by using an IP address assigned to each channel.

Recently, in order to increase the transmission efficiency of broadcast signals, the broadcast signals of all channels are transmitted to the router or L3 switch equipped with the Internet Group Management Protocol (IGMP) function without directly transmitting the broadcast signals from the Internet broadcast server to each user terminal. In this case, the user terminal can receive a broadcast signal from the router or the L3 switch.

On the other hand, when the user terminal selects another channel while watching the IPTV in the structure, the IPTV receives and outputs the broadcast signal of the newly tuned channel from the router, and outputs the IPTV from the time when the specific channel is tuned by the user. It takes a predetermined time until the broadcast signal is reproduced and output.

The time required in the above process is called a channel zapping time.

Since the user satisfaction decreases as the channel travel time is longer when the user moves the channel, methods for shortening the channel travel time during the development of IPTV technology have been actively studied.

Meanwhile, in the video data constituting the broadcast signal, a GOP (Group of Picture) is composed of a plurality of I frames and a plurality of P frames dependent on each I frame. The GOP is an I frame period of the screen collection layer when I and P frames are transmitted on the time axis, the I frame is information about a self-compressed video signal irrespective of temporal change, and the P frame is error information with the I frame. The GOP shown in FIG. 1 has a structure consisting of I-p1-p2-p3-p4-p5-p6-p7.

According to the frame structure, the IPTV can output the image information of the corresponding channel by reflecting the P frame to the I frame only when the I frame is received. Therefore, if the image frame received at the time (D) when the user changes the channel to the B channel is not an I frame but a P frame (Bp3), the IPTV receives the next I frame (Bi8) as shown in FIG. Until this time, the channel zapping time also occurs in this portion Bp3 to Bp7.

That is, according to FIG. 1, since the video frame of the B channel received at the time when the B channel is tuned while playing and reproducing the video frame of the A channel is the P frame Bp3, the IPTV receives the I frame Bi3 in the following order. It is impossible to perform the playback process on the video frame for a period until the time becomes (Bp3 to Bp7). Therefore, a channel shift time occurs during the corresponding period (Bp3 to Bp7), and the user cannot watch the B channel broadcast during the channel shift time.

The present invention has been made in view of the above circumstances, and the user can store the I frame video signal of an adjacent channel when channel selection in IPTV (Internet Protocol TeleVision), and decode by using the I frame stored in advance when the adjacent channel is selected. The purpose of the present invention is to minimize the channel shifting time (Zapping time) when the channel is changed.

In order to achieve the above object, a video frame processing method in an IPTV according to the present invention includes the steps of: (a) receiving broadcast information of a channel and a channel adjacent to the channel, and (b) broadcasting information of the channel. (C) storing the I frame of the image frame among the broadcast information of the adjacent channel, and (d) if the adjacent channel is selected, the stored I frame and the image frame received from the adjacent channel. And decoding the P frame together to output image information on the adjacent channel.

Preferably, in the present invention, the adjacent channel of the step (a) is characterized in that the first channel or the first channel downlink channel of the channel.

In the present invention, the step (a) is characterized in that it comprises the step of transmitting a broadcast information message for the channel and the adjacent channel on the basis of pre-stored channel information.

Preferably, the present invention further includes (e) receiving broadcast information of an adjacent channel for the adjacent channel, and (f) storing an I frame of an image frame among the broadcast information of the adjacent channel. It is done.

Preferably, in the present invention, the step (d) may include (d1) reading a pre-stored I frame for the adjacent channel, and (d2) sequentially performing a P frame of the I frame and an image frame received for the adjacent channel. It characterized in that it comprises a process of decoding.

In order to realize the above object, an image frame processing system in an IPTV according to the present invention is a demultiplexer for dividing and outputting a video frame for a broadcast signal for a channel and an adjacent channel for each channel, and in the video frame for each channel. I frame discriminating units for distinguishing and storing frames in a buffer and outputting the image frame, first switching units for switching output paths of the output terminal of the buffer and the output terminal of the I frame discriminating unit for each channel, and for each channel of the buffer. Decoders for decoding and outputting an I frame output from an output terminal and a P frame output from an output terminal of the I frame discriminator, a second switching unit for switching an output path to an output terminal of the decoders, and the channel selection channel from a broadcast server; Receiving the broadcast signal of the adjacent channel to the station Soon as the reproduction output channel at the same time, the I frame of the image frame of the adjacent channel, characterized in that it comprises a control unit for controlling the overall apparatus to be stored in the buffer.

Preferably, in the present invention, if a specific channel is tuned with channel information, the controller transmits a broadcast request message to the broadcast server using connection information of the channel and access information of an adjacent channel of the channel. It is characterized by.

Preferably, in the present invention, the I frame discrimination unit determines whether the image frame is an I frame based on header information of the image frame.

Preferably, in the present invention, the control unit controls the first switching unit so that the output path of the output terminal of the buffer corresponding to the channel selection channel and the output path of the output terminal of the I frame discrimination unit is output to the decoder corresponding to the channel selection channel. do.

Preferably, in the present invention, the controller controls the first switching unit to be switched on with the output terminal of the I frame discriminating unit after being switched on for a predetermined time with the output terminal of the buffer.

Preferably, the predetermined time in the present invention is characterized in that the I frame transmission time.

Preferably, the control unit is characterized in that for controlling the switching terminal of the second switching unit to output the image information of the selected channel.

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

2 is a main block diagram of a video frame processing system in an IPTV according to an embodiment of the present invention.

As shown in FIG. 2, the video frame processing system according to the embodiment of the present invention includes a demultiplexer 20, a plurality of I frame distinguishing units 30, a plurality of buffers 40, and a first switching unit. 50, a plurality of decoders 60, 62, and 64, a second switching unit 70, a control unit 80, a command input unit 90, and an IGMP message generating unit 100.

The operation of each unit shown in FIG. 2 will be described in more detail.

The demultiplexer 20 divides the broadcasting signals corresponding to the Q-1 channel, the Q channel, and the Q + 1 channel transmitted from the router 10 for each channel and outputs the output signals to the output terminals 20a, 20b, and 20c. Perform.

The I frame discriminator 30, 32, 34 distinguishes I frames from the image frames for each channel output from the demultiplexer 20, stores them in the buffers 40, 42, 44 connected to the rear stage, and simultaneously demultiplexes ( 20 to output a video frame for each channel output from the first switching unit (50).

The buffers 40, 42, and 43 perform a function of outputting the I frame information stored under the control of the controller 80 to the first switching unit 50.

The first switching unit 50 sets a path such that the I frame of the channel is output to the decoder side when a specific channel is tuned by the switching control signal of the controller 80, and when the transmission for the I frame is completed, This function sets the path so that the P frame of the channel and the I frame of the next sequence are continuously output to the decoder side.

The decoders 60, 62, and 63 decode I and P frames of the channel and output image information on the channel to the output side.

The second switching unit 70 performs a function of setting a path so that the image information output from the decoders 60, 62, and 63 can be transmitted to the output terminal under the control of the controller 80.

The controller 80 manages connection information of each channel, manages adjacent channel information of each channel, and generates a broadcast request message (IGMP join message) so that broadcast signals of the corresponding channel and the adjacent channel are received according to channel selection of the user. It performs a function of controlling the IGMP message generating unit 100 to generate. In addition, the controller 80 receives the I frame from the buffer storing the I frame among the image information of the corresponding channel when the channel is changed to an adjacent channel, and then the I frame and the P frame received thereafter are decoded by the decoder 60. 62 and 64 to control the first switching unit 50 to be output. The controller 80 controls the output paths of the decoders 60, 62, and 64 so that the video information of the channel selected by the user can be output. The controller 80 includes a channel-specific IP multicasting group address table as shown in FIG. 5 to manage access information of each channel.

The command input unit 90 includes a remote controller having a control panel or a keypad, and performs a function of receiving a command such as channel input or volume adjustment from a user.

The IGMP message generating unit 100 performs a function of generating a broadcast request message for each channel by using the IP multicasting group address when the IP multicasting group address for channel selection is transmitted under the control of the control unit 80. do.

The header of the broadcast request message may be configured as shown in FIG. 3.

The multicasting group MAC address 100a is a group identifier of an Internet broadcast that the IPTV wants to watch.

Source MAC address 100b is a second layer address identifier assigned to every frame transmitted by IPTV.

Source IP address 100c is an IP address identifier that IPTV uses when using the Internet.

IP multicasting group address 100d is a multicasting address identifier for Internet broadcasting established by the International Organization for Standardization.

UDP port number 100e is a UDP port identifier of IPTV.

Next, a method of processing an image frame in an IPTV according to an embodiment of the present invention will be described in detail with reference to the system configuration diagram shown in FIG. 2 and the flowchart shown in FIG. 4.

First, when a channel tuning signal is input through the command input unit 90 (S2), the controller 80 is adjacent to a broadcast request message for a channel (hereinafter, "Q") tuned through the IGMP message generator 100. A broadcast request message for each channel (hereinafter, "Q-1" and "Q + 1") is generated and transmitted to the router 10 (S4). For example, the IP multicasting group address of each channel may be as shown in FIG. 5, and each channel may be distinguished through the IP multicasting group address.

When the router 10 transmits the broadcast information of each channel requested through the broadcast request message to the demultiplexer 20, the demultiplexer 20 outputs an image frame of each channel included in the broadcast information. 20a, 20b, and 20c) to output them separately (S6 and S8).

On the other hand, the controller 80 controls the first switching unit 50 to output the image frame output from the I frame discriminating unit 32 in which the image frame of the Q channel is processed to the decoder 62.

That is, the controller 80 switches on the second switching terminal 50b3 of the first switching unit 50 to the output terminal 50b1 of the buffer 42 for a predetermined time (for example, one frame transmission time), and then switches on the corresponding time. After the elapse of time, by switching on the output terminal 50b2 of the I frame discriminator 32, the I frame of the Q channel stored in the buffer 42 and the P frame transmitted through the I frame discriminator 32 are decoded by the decoder 62. Output to. In addition, the controller 80 controls the second switching unit 70 so that the fourth switching terminal 70d is switched on to the output terminal 70b of the decoder 62. As a result, image information from which the I and P frames of the Q channel are decoded is output from the second switching unit 70 (S10).

Subsequently, the controller 80 confirms whether a channel change is input from the command input unit 90 (S12), and when the channel change input is confirmed (Yes in S12), the selected channel is an adjacent channel (Q-1 channel or Q-). 2 channels) (S14).

As a result of the determination in step S14, if the selected channel is an adjacent channel (Yes in S14), a broadcast request message for accessing the adjacent channel of the selected adjacent channel is transmitted (S16). At the same time, the first switching unit 50 and the second switching unit 70 are controlled to process the image frame of the channel identified in step S12.

For example, if the channel identified in step S12 is a one-step down channel (Q-1 channel) with respect to the Q channel (see FIG. 6), the controller 80 determines that the adjacent channel of the Q-1 channel is a Q-2 channel, In contrast to the Q channel, since the broadcast signal of the Q channel is already being transmitted, a broadcast request message for accessing the Q-2 channel is generated and output through the IGMP message generator 100. The video frame of the broadcast signal of the Q-2 channel received through the broadcast request message is output to the third output terminal 20c of the demultiplexer 20. In addition, under the control of the controller 80, the first switching terminal 50a3 of the first switching unit 50 is switched on to the output terminal 50a1 of the buffer 40 and then the output terminal of the I frame discriminating unit 30. An image in which I and P frames of the Q-1 channel are decoded by being switched on at 50a2 and being switched on at the output terminal 70a of the decoder 60 of the second switching unit 70. Information is output from the second switching unit 70.

 On the contrary, if the channel identified in step S12 is the first upstream channel (Q + 1 channel) for the Q channel (see FIG. 7), the controller 80 determines that the adjacent channel of the Q + 1 channel is the Q channel and the Q + channel. On the other hand, since the broadcast signal of the Q channel is already being transmitted, it generates and outputs a broadcast request message for accessing the Q + 2 channel through the IGMP message generator 100. The video frame of the broadcast signal of the Q + 2 channel received through the broadcast request message is output to the first output terminal 20a of the demultiplexer 20. In addition, under the control of the controller 80, the first switching terminal 50c3 of the third switching unit 50 is switched on to the output terminal 50c1 of the buffer 40 and then the output terminal of the I frame discriminating unit 30. Switched on at 50c2, the switching terminal 70d of the second switching unit 70 is switched on to the output terminal 70c of the decoder 60, so that the I frame and P frame of the Q + 1 channel are decoded. Information is output from the second switching unit 70.

Meanwhile, while performing step S18, the controller 80 proceeds to step S12 to monitor whether a channel change command is input and waits for a channel change by a user.

In addition, as a result of the determination in step S14, if the channel identified in step S12 is not an adjacent channel based on the channel currently tuned in, the controller 80 proceeds to step S4 and repeatedly performs steps S4 to S18 described above.

On the other hand, if the channel tuned in step S2 is the Q channel, the video frame of the adjacent channel (Q-1 channel, Q + 1 channel) for the Q channel is the first output terminal 30, the first of the demultiplexer 20 It is output to 3 output stage 34, respectively.

Accordingly, the I frame discriminator 30 checks whether the received image frame of the Q-1 channel is an I frame (S20), and when the I frame is checked (YES in S20), stores the I frame in the buffer 40. (S22), the I frame discriminating unit 34 checks whether the received video frame of the Q + 1 channel is an I frame (S30), and if the I frame is checked (Yes in S30), the I frame is transferred to the buffer 44. Save (S32). In the buffers 40 and 44, I frames for the corresponding channel are updated and stored in GOP units.

According to the video frame processing method in the IPP according to the embodiment of the present invention described above, as shown in FIG. 7, when a channel change request from the user to the B channel is requested at the time D while the user is watching the A channel, Prior to transmitting the image frame of the B channel, the channel movement time can be shortened from Z1 (see FIG. 1) to Z2 by transmitting and processing the I frame of the B channel from the buffer provided for the B channel to the decoder. If the GOP (Group Of Picture) is configured with I-P1-P2-P3-P4-P5-P6-P7, if the channel is changed immediately after the Bi1 frame is received, the maximum 5 frame transmission time is the I frame transmission time. It can be shortened.

As described above, according to the video frame processing method and system in the IPTV according to the embodiment of the present invention, it is possible to shorten the channel moving time (zapping) generated when changing the channel in the IPTV, thereby improving the quality of video service Has the effect that it can.

On the other hand, the present invention is not limited to the above-described embodiment, but can be modified and modified within the scope not departing from the gist of the present invention, such modifications and changes should be regarded as belonging to the following claims. will be.

Claims (13)

(a) receiving a broadcast channel and broadcast information of a channel adjacent to the channel; (b) reproducing and outputting broadcast information of the channel; (c) storing an I frame of an image frame among broadcast information of the adjacent channel; And (d) if the adjacent channel is selected, decoding the stored I frame and the P frame of the image frame received from the adjacent channel together and outputting image information on the adjacent channel; Image frame processing method in IPTV. The method of claim 1, wherein the adjacent channel of the step (a) is Characterized in that the first channel upstream channel or the first channel downlink channel Image frame processing method in IPTV. The method of claim 1, wherein the step (a) And transmitting a broadcast information message for the selected channel and the adjacent channel based on previously stored channel information. Image frame processing method in IPTV. The method of claim 1, (e) receiving broadcast information of an adjacent channel for the adjacent channel; And (f) storing the I frame of the image frame among the broadcast information of the adjacent channel. Image frame processing method in IPTV. The method of claim 1, wherein (d) (d1) reading previously stored I frames for the adjacent channel; (d2) sequentially decoding P frames of the image frames received for the I frame and the adjacent channel; Image frame processing method in IPTV. A demultiplexer for dividing and outputting an image frame for a broadcast signal for a channel and an adjacent channel for each channel; I frame discriminating units for distinguishing I frames from the image frames for each channel and storing the I frames in a buffer and outputting the image frames; First switching units for switching output paths to the output terminal of the buffer and the output terminal of the I frame discriminator for each channel; Decoders for decoding and outputting an I frame output from an output end of the buffer and a P frame output from an output end of the I frame discriminator for each channel; A second switching unit for switching an output path to an output terminal of the decoders; And And a control unit for controlling the overall apparatus such that the broadcast channel of the channel and the adjacent channel are received from a broadcast server, and the channel is reproduced and output, and the I frame of the video frame of the channel is stored in the buffer. By Image Frame Processing System in IPTV. The method of claim 6, wherein the control unit When a specific channel is tuned with channel information, a broadcast request message is transmitted to the broadcast server by using access information of the channel and access information of an adjacent channel of the channel. Image Frame Processing System in IPTV. 7. The apparatus of claim 6, wherein the I frame discriminators It is determined whether the video frame is an I frame based on the header information of the video frame. Image Frame Processing System in IPTV. The method of claim 6, wherein the control unit And controlling the first switching unit to output an output path of a buffer corresponding to the channel selection channel and an output path of the output terminal of the I frame discrimination unit to a decoder corresponding to the channel selection channel. Image Frame Processing System in IPTV. The method of claim 9, wherein the control unit And after switching on the output terminal of the buffer for a predetermined time, controlling the first switching unit to switch on with the output terminal of the I frame distinguishing unit. Image Frame Processing System in IPTV. The method of claim 10, wherein the predetermined time I frame transmission time, characterized in that Image Frame Processing System in IPTV. The method of claim 6 or 9, wherein the control unit And controlling the switching terminal of the second switching unit to output the image information of the selected channel. Image Frame Processing System in IPTV. The method of claim 6 or 7, wherein the adjacent channel is Characterized in that the first channel upstream channel or the first channel downlink channel Image Frame Processing System in IPTV.

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