KR20070007683A - Apparatus and method for reducing zapping time in digital broadcasting using additional channel - Google Patents

Abstract

A device and a method for reducing a zapping time in broadcasting by using an additional channel are provided to reduce time required for display processing by using an additional clean channel for channel conversion, thereby realizing the channel conversion within a short time without waiting. In a method for reducing a zapping time in digital broadcasting channel conversion, an additional channel for channel conversion is set in a single physical channel and transmitted with digital broadcasting standard channels. The additional channel, in which display processing is finished(S630), is displayed on a screen(S640) for the time required for display processing regarding the transmitted standard channels, in response to user's channel conversion request(S610,S650-S660).

Description

Apparatus and Method for Reducing Zapping Time in Digital Broadcasting Using Additional Channel}

1 is a diagram showing a relationship structure between a physical channel and a logical channel used for digital broadcasting.

2 is a diagram illustrating a physical channel configuration of a digital broadcasting system according to the present invention.

3 is a block diagram of a digital broadcast receiving system to which the present invention is applied.

4 is a diagram illustrating a processing procedure of a broadcast standard channel in a digital broadcasting system.

5 is a diagram illustrating an operation control flow between a standard channel and an additional channel for channel switching according to the present invention.

6 is a view showing a broadcast channel switching process according to a first embodiment of the present invention.

7 is a view showing a broadcast channel switching process according to a second embodiment of the present invention.

* Description of the symbols for the main parts of the drawings *

300: digital broadcast receiving system 310: tuner

340: MPEG decoder 360: reception limit processing unit

370: control unit 400: digital broadcast transmission system

The present invention relates to channel switching of digital broadcasting, and more particularly, a digital broadcasting channel switching time reduction apparatus using an additional channel used when switching channels by using additional channels of separate clean, low quality, and high compression for channel switching. It is about a method.

Digital broadcasting compresses program data for each channel with high efficiency based on the MPEG encoding standard, and multiplexes and transmits programs corresponding to a plurality of channels based on a digital modulation method for each transmission medium. Due to this characteristic, digital broadcasting can broadcast dozens or hundreds of channels without using a large amount of repeaters as in analog broadcasting. In other words, digital broadcasting has the advantage of eliminating the shortage of broadcasting channels by significantly improving the efficiency of frequency use compared to analog broadcasting.

In addition, multi-use of professional paid broadcasting and interactive service broadcasting software is possible, which has the advantage that the broadcasting industry can be developed into a composite media industry.

For these reasons, digital broadcasting is being expanded to cable and terrestrial broadcasting, including satellite broadcasting, and is emerging as a next generation broadcasting technology.

Despite the many advantages of digital broadcasting, it has to be acknowledged that there are some disadvantages compared to analog broadcasting, one of which is channel switching (or zapping) time.

Channel switching time refers to the time taken from the time of zapping to the complete zapping. In analog broadcasting, there is little channel switching time, whereas in digital broadcasting, a channel switching time of 1 to 2 seconds occurs. It's about a second or two, but it can be a big complaint for viewers who are used to analog broadcasting.

Channel switching time occurs regardless of digital cable, terrestrial or satellite broadcasting. Especially, digital cable broadcasting is known to have a weaker channel switching time than other broadcasting media.

The main causes of current channel switching time include command processing, network delay, STB layer delay, STB jitter buffer delay, and MPEG decoders. The time can be mentioned. Among them, the conditional access system (CAS) for content protection and the delay time in the process are the major part.

In general, in providing a digital broadcast service, a digital transmission system transmits a broadcast stream (MPEG-2) defined in a standard to a reception system. The reception system tunes the broadcast center frequency of the channel to which the program belongs in order to display the stream of the received broadcast channel on a TV screen. A stream of a single program requested by a viewer among the tuned transport streams (TSs) performs CAS authentication through communication with a transmission system. When CAS certification is completed, the decoder performs decoding to display the screen.

Each time the channel is switched, this tuning, CAS authentication, and decoding process must be repeated, which takes considerable time (about 1 to 2 seconds). Due to this channel switching time, when the viewer requests channel switching, the image being watched is cut off and no image is displayed on the screen during the channel switching time. This phenomenon can make viewers feel not only bored but also unpleasant.

As a solution to this problem, a broadcast reception system capable of decoding a multi-stream using a plurality of broadcast information processing units and buffers can be considered. However, there is a limit in decoding all channels in advance and storing them in a buffer.

Here, a need arises for a method of reducing channel switching time by effectively performing channel switching without having a tuner capable of simultaneously processing several physical channels.

In order to solve the above problems, the present invention provides a clean, low quality, high compression additional channel together with a standard channel to a single physical channel without a module such as a tuner capable of processing a plurality of physical channels. An object of the present invention is to provide an apparatus and method for reducing digital broadcast channel switching time using an additional channel to be used.

According to an aspect of the present invention, there is provided a method for reducing a digital broadcast channel switching time, comprising: setting a separate additional channel for channel switching in one physical channel and transmitting the same together with the digital broadcast standard channel; And when the channel switching request by the user occurs, displaying the additional channel on which the display processing is completed on the screen for the time required for the display processing for the transmitted standard channel.

The additional additional channel is a high compression, low quality compared to the digital broadcast standard channel, characterized in that the channel does not receive reception processing or copy protection processing.

The displaying step includes: performing display processing for the standard channel and the additional channel; Displaying an additional channel on which display processing is completed; And when the display processing for the standard channel is completed, stopping the display for the additional channel and performing the display for the standard channel.

The displaying step may also include performing display processing for the standard channel and the additional channel; Displaying an additional channel on which display processing is completed; And stopping the display of the additional channel and performing the display of the completed standard channel when the channel switching event by the user ends.

Termination of the channel switching event by the user may occur when a channel is fixed for a specific channel for a specific time or when an intention of indicating termination by the user is input.

Display processing for the standard channel includes at least one of tuning, reception restriction authentication, and decoding.

Meanwhile, the display processing for the additional channel includes at least one of tuning and decoding, but does not include a reception restriction authentication process.

The apparatus for reducing digital broadcast channel switching time according to another aspect of the present invention receives a digital broadcast standard channel transmitted through one physical channel and a separate additional channel set for channel switching, and requests for channel switching by a user If so, the control unit performs display processing for the standard channel and the additional channel, and displays the additional channel on a screen for a time required for display processing for the standard channel.

According to another aspect of the present invention, there is provided a digital broadcasting system comprising: a digital broadcast transmitting apparatus for setting a separate additional channel for channel switching in one physical channel and transmitting the same together with the digital broadcasting standard channel; And a digital broadcast reception device which performs display processing for the standard channel and the additional channel when a channel switching request is generated by a user, and displays the additional channel on a screen for a time required for display processing for the standard channel. It includes.

Hereinafter, a preferred embodiment according to the present invention will be described in detail with reference to the drawings.

1 illustrates a relationship structure between a physical channel and a logical channel used for digital broadcasting.

As shown in Fig. 1, one physical channel of digital broadcasting is allocated a band of about 6 MHz, and one physical channel includes a plurality of standard channels for broadcasting (1 to N). In this case, the system is usually designed so that the capacity occupied by multiple standard channels constituting one physical channel is smaller than the capacity of the entire physical channel. In such a case, an extra band is left in addition to the space occupied by a plurality of standard channels in one physical channel.

In the present invention, it is intended to use such an extra band, and look at the configuration of the channel according to the present invention through FIG.

2 illustrates a physical channel configuration of a digital broadcasting system according to the present invention.

As shown in Figure 2, the present invention uses a separate additional channel in addition to the standard channel for one physical channel. The standard channel and the additional channel include images of the same broadcast, and are generated in the digital broadcast transmission system and transmitted to the reception system.

In the present invention, the additional channel to be used as information for channel switching is a stream channel to which no CAS (Conditional Access System) or CP (Copy Protection) is set. The additional channel is composed of a stream of lower quality that lowers the quality of the standard channel. The quality of the additional channel is lower than that of the original screen, but optimized so that the viewer can grasp the contents of the screen. This channel has a lower bit rate than the standard channel, and can transmit more broadcast programs than the standard channel when using the same bandwidth.

As an example, if the profile and level of the current standard channel MPEG is Main Profile Main Level (MP @ ML), an additional channel may use MP @ LL, which is a lower level than the standard channel. The main profile is defined to support most applications and offers video compression rates of 2 to 15 Mbps. Simple profiles, on the other hand, are designed to reduce costs than using the main profile, and have relatively low video processing requirements.

Profiles and levels in MPEG-2 provide the flexibility to choose the appropriate class of encoders and decoders for your application. It is divided into several stages. Profiles include Simple Profile, Main Profile, SNR Scalable Profile, Spatially Scalable Profile, and High Profile. The levels include High Level, High-1140 Level, Main Level, and Low Level. MPEG-2 combines these profiles and levels to define eleven classes. For example, the main profile at the high level is defined to be capable of providing 1920 pixels / line, 1152 lines / frame, and 60 frames / second without the data bit rate exceeding 80 Mbit / sec.

On the other hand, the additional channel has a lower transmission capacity than the standard channel, so the transmission capacity of the additional channel does not change much. In addition, it may be desirable to use a compression technique having a higher compression rate than that used for the standard channel.

That is, the present invention intends to configure a physical channel including both the standard channel and the additional channel, and display the additional channel during the processing time for channel switching of the standard channel.

3 shows a block configuration of a digital broadcast receiving system to which the present invention is applied.

The digital broadcast reception system includes a tuner 110 for tuning a desired channel from a broadcast signal received in an analog form, and a demodulator 120 for demodulating the tuned analog signal into a digital signal. The demodulator 120 transmits the reception restriction related data, that is, the key information and the viewing authority information for each program, to the reception restriction processing unit 160.

When the subscriber selects a program channel, the conditional access system (CAS) 160 checks whether the subscriber has the right to view the corresponding program channel according to the viewing right information for each program, In this case, the encrypted broadcast data is descrambled according to the key information.

The demultiplexer 130, which has received the decoded signal through the reception limit processing unit 160, demultiplexes the broadcast data converted into the digital signal form and converts the broadcast data into the MPEG type broadcast data. At this time, video data of the broadcast data output from the demultiplexer 130 is in the MPEG 2 form, and audio data is in the MPEG 1 form.

The MPEG decoder 140 decompresses the data output from the demultiplexer 130 into a broadcast signal by decompressing it according to the MPEG method, and the graphic module 150 manipulates the converted broadcast signal to be displayed on a digital TV. . The manipulated broadcast signal is converted into an analog signal form by an encoder (not shown) and transmitted to the digital TV.

On the other hand, when a channel switching request from the user occurs, the controller 170 performs processing for channel switching. Channel switching processing refers to a series of operations for displaying an image of a channel on a screen, such as tuning for a selected channel, CAS authentication, and decoding. In the present invention, processing is performed for additional channels as well as broadcast standard channels. The additional channel stream takes less time for CAS authentication and is transmitted with less transmission capacity than the standard channel, resulting in shorter processing time compared to the standard channel.

The controller 170 checks the state of each processing in real time and when the processing for the additional channel is completed, displays the broadcast of the corresponding channel on the screen. At the same time, it waits for the processing of the standard channel to be completed, stops broadcasting the additional channel, and displays the standard channel on the screen.

The digital broadcast reception system may further include a network interface for a function of receiving guide information of a program through a network in addition to the above components.

In FIG. 3, only the main role of the present invention is illustrated, and various additional function blocks may be added in addition to those illustrated.

4 illustrates a processing procedure of a broadcast standard channel in a digital broadcasting system.

The digital broadcast reception system 300 receiving the broadcast standard channel from the digital broadcast transmission system 400 performs processing for displaying on the screen of the TV 500 through tuning, CAS, and decoding for the corresponding channel. Of course, in the actual broadcasting system, many more complicated processes occur, but FIG. 4 illustrates the important processes that may occur in the channel switching process.

Whenever channel switching occurs, the process as shown in FIG. 4 must be repeated in the digital broadcast transmission system 300. In other words, the tuning, CAS, and decoding for the target channel to be switched must be newly performed each time. These processes have a time that can never be ignored, especially in the CAS process has already been seen.

5 shows an operation control flow between a standard channel and an additional channel for channel switching according to the present invention.

FIG. 5 conceptually illustrates an operation of the digital broadcast reception system 300 when an additional channel is added to one physical channel according to the present invention.

When channel switching occurs, tuning, CAS, and decoding are performed on broadcast standard channels, and only tuning and decoding are performed on additional channels. The additional channel is a lower quality, higher compression channel than the broadcast standard channel, and the CAS process does not need to go through, so the display processing time of the additional channel can be significantly shortened compared to the broadcast standard channel.

Therefore, when channel switching occurs, the display on the TV 500 screen is made first for the additional channel, and waits until the processing process for the broadcast standard channel is completed to display the standard channel. That is, the display for the additional channel continues only until the tuning, CAS, and decoding process for the broadcast standard channel is completed.

This process can be understood as the concept of switching as shown in FIG. The actual display process connected to the TV 500 screen can be understood as a switching operation between a broadcast standard channel and an additional channel. Display processing is performed for each of the broadcast standard channel and the additional channel, and which channel to display is determined by which channel the display screen is connected to.

6 shows a broadcast channel switching process according to the first embodiment of the present invention.

If channel switching occurs by the user (S610), display processing for the additional channel and the standard channel is simultaneously started (S620). At this time, operations such as tuning, CAS, and decoding are performed on the standard channel, and tuning, decoding, and the like except for the CAS process are performed on the additional channel. The additional channel contains lower quality images than the standard channel, so the decoding time is much less than that of the standard channel.

When the processing for the additional channel is completed (S630), the additional channel is displayed on the TV screen (S640). While the additional channel is displayed, the digital broadcast reception system 300 continuously monitors whether the processing for the standard channel is completed (S650). When the completion of the display processing for the standard channel is detected, the display for the additional channel is stopped and the decoded standard channel is displayed (S660).

FIG. 6 is written based on one channel switching event, and each time a channel switching occurs, a process flow of the process as shown in FIG. 6 is generated one by one.

That is, according to the first embodiment of the present invention shown in FIG. 6, whenever a channel switching event occurs, processing of the additional channel and the standard channel is performed simultaneously, and the display of the additional channel is performed before the processing of the standard channel. Perform the display on the standard channel at the same time as the completion of.

7 shows a broadcast channel switching process according to a second embodiment of the present invention.

The embodiment of FIG. 7 is an embodiment that can be effectively applied when the user starts channel switching and performs channel switching to several channels.

If channel switching by the user occurs (S710), the display for the additional channel and the standard channel processing (S720). Waiting for the completion of the processing for the additional channel (S730), and displays the additional channel (S740). The procedure so far is not much different from the embodiment of FIG. 6.

In FIG. 7, in consideration of a frequent channel change request by a user, the user waits for the completion of a channel change event and performs display on a standard channel.

That is, after waiting for the end of the channel switching event (when the channel is fixed for a specific channel for a specific time after the channel switching event occurs or if there is an artificial selection of the viewer to continue watching the specific channel), the channel switching event is waited (S750). Only when is terminated, the standard channel is monitored whether the processing is completed (S760), and the display for the additional channel is stopped at the same time (S770).

If the channel change event does not end and the channel change occurs continuously (S710), the process returns to the first step and repeats the process from the processing step (S720) to the additional channel display step (S740) for the additional channel and the standard channel. . In the case of a channel where the user stayed for a while and then switched to another place, the display of the standard channel is not performed.

That is, FIG. 7 is different from the procedure of FIG. 6 generated whenever a channel switch event occurs, and the display of the standard channel is performed only when the channel switch event ends. to be.

The present invention eliminates the boredom of digital TV users waiting for channel switching time by reducing the time spent on display processing using a separate clean channel for channel switching.

Claims (21)

In the channel switching time reduction method of digital broadcasting, Setting a separate additional channel for channel switching in one physical channel and transmitting it together with the digital broadcasting standard channel; Wow And when the channel change request by the user occurs, displaying the additional channel on which the display processing is completed on the screen during the time required for the display processing for the transmitted standard channel. The method of claim 1, The additional additional channel is a digital broadcast channel switching time reduction method, characterized in that high compression, low quality compared to the digital broadcast standard channel. The method of claim 1, The additional additional channel, A method for reducing digital broadcast channel switching time, characterized in that the channel has not been subjected to reception restriction processing or copy protection processing. The method of claim 1, The display step, Performing display processing for the standard channel and the additional channel; Displaying an additional channel on which display processing is completed; And Stopping display for the additional channel and performing display for the standard channel when the display processing for the standard channel is completed. The method of claim 1, The display step, Performing display processing for the standard channel and the additional channel; Displaying an additional channel on which display processing is completed; And Stopping the display of the additional channel and performing the display of the completed standard channel when the channel switching event by the user is terminated. The method of claim 5, The termination of the channel switching event by the user is generated when the channel is fixed for a specific channel for a specific time or when the end indication input by the user is input. The method according to claim 4 or 5, And the display processing for the standard channel comprises at least one of tuning, reception restriction authentication, and decoding. The method according to claim 4 or 5, And the display processing for the additional channel comprises at least one of tuning and decoding. The method of claim 8, And the display processing for the additional channel does not include a reception restriction authentication process. In the apparatus for reducing channel switching time of digital broadcasting, Receives a digital broadcast standard channel transmitted through one physical channel and a separate additional channel set for channel switching, and performs display processing for the standard channel and the additional channel when a channel switching request is generated by a user. And a control unit which displays the additional channel on a screen during the time required for display processing for the standard channel. The method of claim 10, The additional additional channel is a digital broadcast channel switching time reduction device, characterized in that the high compression, low quality compared to the digital broadcast standard channel. The method of claim 10, The additional additional channel is a digital broadcast channel switching time reduction apparatus, characterized in that the channel does not receive the reception restriction processing or copy protection processing. The method of claim 10, And the display processing for the standard channel comprises at least one of tuning, reception restriction authentication, and decoding. The method of claim 10, And the display processing for the additional channel comprises at least one of tuning and decoding. The method of claim 14, And the display processing for the additional channel does not include a reception restriction authentication process. In a digital broadcasting system, A digital broadcast transmission apparatus for setting an additional additional channel for channel switching in one physical channel and transmitting the same together with the digital broadcast standard channel; Wow When a channel switching request by a user occurs, the digital broadcast receiving apparatus performing display processing for the standard channel and the additional channel and displaying the additional channel on the screen for a time required for display processing for the standard channel. Digital broadcasting system comprising. The method of claim 16, The additional additional channel is a digital broadcasting system, characterized in that high compression, low quality compared to the digital broadcasting standard channel. The method of claim 16, The additional additional channel, A digital broadcasting system, characterized in that the channel is not subjected to reception restriction processing or copy protection processing. The method of claim 16, And display processing for the standard channel comprises at least one of tuning, reception restriction authentication, and decoding. The method of claim 16, And the display processing for the additional channel comprises at least one of tuning and decoding. The method of claim 20, And the display processing for the additional channel does not include a reception restriction authentication process.

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