KR100343702B1 - Time display method and apparatus - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a time signal display method and apparatus, and more particularly, to transmit accurate time signal information by transmitting receiving reference time information with respect to a delay element at a transmitter in consideration of delay factors. The purpose is to display. The present invention for this purpose is a first step of determining whether the TDT information from the transmitting side reflecting the delay element of the broadcast medium is detected, and if the TDT information is detected, decoding the TDT information to update the current time and time signal And determining a display time of the time signal and performing a third step of displaying the time signal image of the bitmap type on the screen when the display time of the time signal image is reached.

Description

Time signal display method and device {TIME DISPLAY METHOD AND APPARATUS}

The present invention relates to digital broadcasting, and in particular, to a method and apparatus for displaying time signal.

In general, the broadcast field transmits time signal information to inform viewers of the current correct time.

In the conventional digital broadcasting, the transmitter provides TS (Time Stamp) information as transmission information for decoding the receiver and matching the video / audio output signal according to the time difference between transmission media, and also transmits the program as part of the PLL of the transmitter and the receiver. Provides Program Clock Referenced (PCR) information.

In addition, the transmitting side transmits Decoding Time Stamp (DTS) and Presentation Time Stamp (PTS) information based on program-related clock (PCR) information.

Figure 1 is a block diagram of a conventional system time clock recovery circuit, as shown therein, which loads a program related clock signal PCR received at an input terminal until the next program related clock PCR is loaded. The counter 140 counting according to (STC), the count value (CNT) of the counter 140 and the program-related clock (PCR) value input to the input terminal at the time when the program-related clock signal (PCR) is input. And a low pass filter / gain unit 120 for adjusting the gain by converting the output value of the subtractor 110 into a voltage and adjusting the gain, and the low pass filter / gain unit 120. And a voltage controlled crystal oscillator (VCXO) 130 for outputting a system time clock (STC) by varying the oscillation frequency in correspondence with the voltage value.

That is, FIG. 1 illustrates a system time clock (STC) based on program-related clock (PCR) information using a voltage controlled crystal oscillator (VCXO) provided in a receiver at a receiving side of the prior art. A circuit for recovering is shown.

Referring to the operation of the prior art as follows.

First, program-related clock (PCR) information present in the adaptation_field information in the transport stream information is loaded into the counter 140 in the receiver.

At this time, the initial value of the counter 140 is a value obtained by converting the first program-related clock (PCR) value loaded into a frequency count value of 27 MHz, and the voltage-controlled crystal oscillator (VCXO) until the second program-related clock (PCR) is received. The count value is increased according to the output clock (STC) of 130).

Thereafter, when the second program-related clock PCR is received, the counter 140 outputs the count value CNT up to the present time to the subtractor 110.

At this time, the subtractor 110 compares the program-related clock (PCR) value received at the input terminal with the local count value (CNT) at the counter 140 and converts the difference into a voltage to convert the low pass filter / gain unit ( 120).

Accordingly, when the low pass filter / gain unit 120 converts the difference value in the subtractor 110 into a voltage to adjust the gain and outputs the result to the voltage controlled crystal oscillator (VCXO) 130, the voltage controlled crystal oscillator 130 ) Outputs the system time clock (STC) corrected by varying the clock frequency corresponding to the input voltage to the internal clock and applies the counter to the counter 140.

In addition, in the conventional digital broadcasting, TDT (Time Description Table) information, which is one of the program guide message (PMM), is provided as information for indicating current time information separately from the program-related clock PCR.

However, since the TDT information in the prior art is time information at the time of transmission from the transmitter, when using a medium such as a satellite, an error element exists if the time required from the transmitting side to the receiving side is relatively long. There is a problem that is not suitable for use with.

In addition, in the prior art, even when providing a time signal to a viewer using TDT information, a display using the GUI (Graphic User Interface) configured differently for each receiver is used to display the same time signal information provided by a transmitter. .

In the prior art, even when the transmitting side digitizes the time signal image and transmits it, it is difficult to expect display of the time signal image matched for each receiver due to an image decoding time point that is different for each receiver.

The problem of the digital broadcasting is explained in comparison with the analog broadcasting as follows.

In analog broadcasting, since video and audio information are transmitted using different frequency bands for each channel, an error of the time signal signaled every hour does not occur for each receiver.

On the other hand, in digital broadcasting, it is difficult to provide accurate time signals depending on the medium (terrestrial wave, satellite or cable) and receiver state used for signal transmission.

That is, in the case of analog broadcasting, since the time signal information transmitted from a broadcasting station is transmitted as a video signal, all receivers may provide the same time signal screen at the same time.

On the other hand, in the case of digital broadcasting, a plurality of programs in one frequency band have time buffers, multiplexed transmissions, and buffers for buffering video and audio information input for each receiver. Time difference may occur.

In the case of digital broadcasting, the time required for the information transmitted from the transmitting side to be output at the receiving side is different depending on the medium used for transmitting the information.

For example, when the transmission using the terrestrial transmission path and the transmission of information using the satellite are compared, the time taken from the transmitting side to the receiving side is different.

Therefore, in digital broadcasting, in order to transmit information having meaning in an instant, such as time signal, transmission in consideration of characteristics of each medium is required before transmitting from the transmitting side.

Accordingly, an object of the present invention is to provide a time signal display method and apparatus invented to notify viewers of correct time signal by solving the inaccuracy of time signals caused by broadcasting media (satellite, terrestrial wave) or receiver-specific characteristics, which are problems in the prior art. There is this.

The first object of the present invention is to provide accurate time information by transmitting reference time information regarding the delay side in consideration of the delay element in the time information transmitted in the conventional digital broadcasting without considering the delay element for each broadcast medium.

Further, a second object of the present invention is to process and provide a time signal image as separate data so that all receivers display the same time signal image at the same time intended by the transmitting side.

1 is a block diagram of a conventional STC recovery circuit.

Figure 2 is an exemplary view showing a lower class of the pseudo class of MHEG standard.

3 is a block diagram of a general MHEG processing apparatus.

4 is a block diagram of a reference time generating device in a transmitter for an embodiment of the present invention.

5 is a block diagram of a visual information display apparatus for an embodiment of the present invention.

6 is a signal flow diagram for an embodiment of the invention.

Explanation of symbols on the main parts of the drawings

410: clock generator 420: clock receiver

430: comparison unit 440: visual information decoding unit

450: visual information generator 510: demultiplexer

520: MHEG engine unit 530: microprocessor

540: graphics processing unit 550: timer

In order to achieve the above object, the present invention provides a receiving side reference time by inspecting the receiving side time information and reflecting the received side time information in the transmitting information, and also provides time information as MHEG (Multimedia Hyper-media Expert Group) information. It is characterized in that all receivers provide the same time signal.

That is, the present invention decodes program-related clock (PCR) information from the transmitting side so that the time delay caused by the current broadcast medium can be known so that the receiving side in which the TDT information is considered a storage medium delay element rather than the transmitting side reference time. All receivers display the same time signal provided by the transmitter by transmitting the time signal image information as bitmap level information which is one of the classes defined by MHEG.

Therefore, the present invention for notifying viewers of the correct time signal as in analog broadcasting by using the delay element of the broadcast medium and the interactive application information as described above, the delay element detection unit for detecting the delay element of the broadcast medium, the transmitting side and the reception A transmitter for converting the detected delay element into a delay time in consideration of delay elements between sides, and a time information generator for generating bit-side type reference time information by adding the obtained delay time to time information. Equipped in; A demultiplexer for detecting TDT information on the receiving side, a timer for counting the current time, and decoding the TDT information when the demultiplexer detects the TDT information, and updating the current time. The MHEG engine unit which judges whether the time of the time signal image is displayed after judging by time, and when the time signal image information of the bitmap type is output by judging that the time signal image is displayed by the MHEG engine unit, the graphic is converted into the form to be displayed on the screen. It is characterized by comprising a processing unit in the receiver.

In addition, the present invention is to determine whether the TDT information from the transmitting side that reflects the delay element of the broadcast medium is detected in order to achieve the above object, and if the TDT information is detected in the above to decode the current time On the contrary, if the TDT information is not detected, determining the current time based on the timer's time, and determining whether the time is the display time of the time signal, and when the time of the time signal is reached, displaying the time signal of the bitmap type on the screen. Characterized by performing the steps.

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

FIG. 4 is a block diagram of a time information generating apparatus for providing reference time information from a transmitting side to a receiving side for an embodiment of the present invention. As shown therein, a clock generator for generating a system time clock (STC) ( 410, a clock receiver 420 for receiving the system time clock STC 'through the broadcast medium, a time information decoder 440 for decoding the time information TDT, and reference time information on the receiving side. The difference between the time information generation unit 450 for generating the TDT and the clock STC STC ', and the time information TDT decoded by the market price information decoding unit 440 is determined. The comparison unit 430 converts the obtained difference value into a delay time of the broadcasting medium and outputs the difference value to the time information generating unit 450.

The operation process of the apparatus for generating visual information for the embodiment of the present invention configured as described above is as follows.

First, when the clock generator 410 generates a system time clock (STC) and the clock receiver 420 receives a system time clock (STC ′) that has passed through a broadcast medium, the comparator 430 determines that the 2 is the second. The difference between the clocks STC STC 'is obtained.

In addition, the time information decoding unit 440 decodes the time table information TDT with the time information transmitted to the broadcasting medium, and inputs the time table information TDT to the comparison unit 430.

At this time, the comparator 430 calculates an accurate delay element of the transmitting side and the receiving side by inputting the decoded time table information TDT and compares the difference with the system time clock STC 'STC'. .

Here, the system time clock (STC) value means a 27 MHz clock count value, and the difference between the transmitter and receiver system time clock (STC) value '1' means 1/27000000 second.

Accordingly, the comparator 430 ignores the value of the unit of seconds or less of the difference value of the system time clock (STC) (STC ') and considers the reference clock used by the transmitter for the remaining values, and thus the delay time due to the broadcast medium. In this case, the converted delay time is input to the time information generator 450 as reference time information on the receiving side.

Accordingly, the time information generator 450 generates the time table information TDT in consideration of the delay time between the transmitter and the receiver.

Thereafter, the time information (TDT) generated by the above process is converted into MHEG information and transmitted through a broadcast medium. The time signal information is transmitted as a bitmap type image.

Meanwhile, the Multimedia Hyper-media Expert Group (MHEG) is a standard developed for interactive multimedia applications in the client server structure of various types and products' platforms. It defines several elements in a hierarchical structure, and each layer is defined as a class. It is.

Among the various classes, there is a visible class that performs a function related to expressing visual materials at a part of the display screen.

That is, the pseudo class refers to an element that exhibits a visual effect to a user, such as a line or a bitmap, and the lower class is as shown in the example of FIG.

Therefore, when the MHEG standard is applied to digital broadcasting, the pseudo information is converted into MHEG information, and the MHEG information is multiplexed together with the information transmitted in the digital broadcasting.

Accordingly, when the information multiplexed at the transmitter is received by the receiver, MHEG information, which is interactive application information, may be extracted and provided to the user.

In general, as shown in the block diagram of FIG. 3, the MHEG processing apparatus includes a demultiplexer 310, an MHEG engine unit 320, a microprocessor 330, and a graphics processor 340.

Referring to the operation of the general MHEG processing device as follows.

First, when the microprocessor 330 transmits the information of the program selected by the user to the demultiplexer 310, the demultiplexer 310 is separated into a packet containing the video and audio information packet and the MHEG information to be viewed.

At this time, the demultiplexer 310 delivers the video and audio information packets to be watched to the video / audio decoder (not shown), and contains the MHEG information at the request of the MHEG engine 320 to process the MHEG information. The packet is delivered to the MHEF engine unit 320.

Accordingly, when the MHEG information is a pseudo grade, the MHEG engine unit 320 transmits the corresponding information to the graphic processor 340 to display the information on the screen.

The MHEG information may be represented by various inputs as interactive information, and may be largely expressed by user input or visual information set by a transmitter.

Therefore, when the MHEG standard is applied to the present invention, the time signal display device for the embodiment is configured as shown in the block diagram of FIG.

That is, the time signal display device according to the present invention includes a timer 550 for counting time itself, a graphic processor 540 for converting a subtitle or time signal into a graphic form, and video / audio information from a transport stream. Demultiplexer 510 for separating the packet with the packet containing the MHEG information, and the packet containing the MHEG information in the demultiplexer 510 is decoded, and if there is time information, the current time is updated with the time information and then time signal When the time to display the time signal is determined by determining the time to display the time signal by determining the time to display the time signal by determining the time to display the time signal when there is no time information. MHEG engine unit 520 to transmit to the 540, a microphone for controlling the operation of the demultiplexer 510, MHEG engine unit 520, graphics processing unit 540 and the timer 550. It is composed of processor 530.

The operation and the effect of the embodiment of the present invention configured as described above will be described with reference to the signal flowchart of FIG.

When the transport stream is input, the demultiplexer unit 510 separates the packet including the video and audio information into a packet including the MHEG information.

At this time, the MHEG engine unit 520 decodes the packet of the MHEG information and searches whether there is TDT information corresponding to the time information.

Accordingly, when the MHEG engine unit 520 detects the TDT information, the microprocessor 530 updates the current time of the timer 550 with reference to the TDT information.

If the MHEG engine unit 520 does not detect the TDT information because no TDT information is received, the microprocessor 530 uses the time from the timer 550 started by the nav clock as the current time. 520 is controlled.

At this time, the MHEG engine 520 decodes the MHEG information for the interactive application received from the demultiplexer 510 and whether the corresponding information of the bitmap type is to be displayed, that is, before a predetermined time (for example, 5 seconds) from the time point. The time at the timer 550 is checked.

Accordingly, when the interactive application information such as the time signal is to be output by the timer 550 or the TDT information at the transmitting side, that is, a predetermined time before the scheduled time, the MHEG engine unit 520 sends the corresponding information to the graphic processing unit 540. The time signal is displayed on the screen by converting it into a graphic form to be displayed on the screen.

That is, the procedure for displaying the time signal image using the MHEG information at the receiving side as described above is the same as the signal flow diagram of Figure 6, briefly described as follows.

First, the MHEG engine unit 520 decodes the receiver reference time information transmitted from the transmitter to update the current time, and determines whether the current time is 5 seconds before the scheduled time.

At this time, if the current time is not five seconds ago, the MHEG engine unit 520 decodes the TDT information until five seconds before the hour.

If the period of the TDT information is long and the time before 5 seconds is not known, the MHEG engine unit 520 reads the time from the internal timer 550 and determines whether the time is 5 seconds before the time.

Accordingly, when it is determined that the time is 5 seconds ago from the TDT information or the time information of the timer 550, the MHEG engine unit 520 outputs the time signal information of the previously decoded bitmap type to the graphic processor 540 to display the time signal image on the screen. Will be displayed.

Here, the transmitting side configures about 5-10 bitmap image information for the transmitted time signal to display the changed visual image every second.

As described in detail above, the present invention provides a receiving side reference time at a transmitter in consideration of a delay factor in a broadcast medium, and uses interactive bitmap information to inform a user of an accurate signal as in analog broadcasting. There is.

In addition, the present invention has the effect of displaying the same time signal image for each receiver by providing the receiving side reference time in consideration of the delay time in the broadcast medium.

The present invention can be applied to fields such as digital broadcasting using different media (terrestrial wave, cable, satellite broadcasting).

Claims (7)

delete delete In the digital broadcasting for transmitting the time information and the time signal image, the first step of determining whether time information reflecting the delay element of the broadcast medium from the transmitting side is detected, and if time information is detected, the time information is decoded to present the present invention. Performing a second step of updating the time and determining whether the time is the display time of the time signal image; and performing a third step of displaying the time signal image of the bitmap type on the screen when the time of the time signal image is reached. . The method of claim 3, further comprising determining the time of the internal timer as the current time when there is no time information. In digital broadcasting, a delay element detection unit for detecting a delay element of a broadcast medium, a conversion unit for converting the detected delay element into a delay time in consideration of the delay element between a transmitter and a receiver, and the delay time obtained above. A time information generator for adding the time information to the receiver to receive the reference time information of the bitmap type; A demultiplexer for detecting TDT information on the receiving side, a timer for counting the current time, and decoding the TDT information when the demultiplexer detects the TDT information, and updating the current time. The MHEG engine unit which judges whether the time of the time signal image is displayed after judging by time, and when the time signal image information of the bitmap type is output by judging that the time signal image is displayed by the MHEG engine unit, the graphic is converted into the form to be displayed on the screen. And a processing unit provided in the receiver. The method of claim 5, wherein the delay element detector generates a system time clock (STC) to obtain a difference between the clock (STC) STC 'as a delay element compared to the system time clock (STC') through a broadcast medium. The hourly display device characterized by the above-mentioned. The time signal display of claim 5, wherein the conversion unit is configured to decode the time information TDT received through the broadcast medium and convert the delay element into a delay time by the broadcast medium in consideration of the time information TDT. Device.