KR20080092097A - Method for displaying closed caption of digital television - Google Patents

Abstract

A method of displaying a closed caption for a digital TV is provided to define processing of closed captions having the same priority to display a current caption with high priority. A method of displaying a closed caption for a digital TV includes a step of detecting closed caption information included in bitstreams(S10), a step of analyzing the detected closed caption information and aligning windows according to priorities thereof(S20), a step of increasing the priority of a current window and aligning the windows when there are windows having the same priority(S30,S40), and a step of displaying a closed caption according to the order of the aligned windows(S50).

Description

How to display captions on digital television {METHOD FOR DISPLAYING CLOSED CAPTION OF DIGITAL TELEVISION}

1 is a structural diagram of DTVCC caption data in a bit stream of a typical digital television.

2 is a flowchart illustrating a caption display method of a digital television according to an embodiment of the present invention.

The present invention relates to a caption display method of a digital television. More particularly, when a digital closed caption is displayed on a digital television, the window is processed by increasing the priority of the current window if the priorities are the same. It relates to a caption display method of a digital television that can be displayed.

Caption is a technology that converts and transmits an auditory message of a television program in the form of an electronic code for a hearing impaired person or language study, and appears as a commentary subtitle on a TV screen. As one of the TV multi-text broadcasting services, it often refers to a subtitle service for the hearing impaired.

A dedicated adapter should be attached to the receiver unless it receives a service of open caption which can be received as a general television receiver. It is called closed caption in that it is a service for a limited viewer as described above.

The terrestrial broadcasting standard for analog TV in the US transmits closed captions such as English and Spanish using the 21st line of the VBI (Vertical Blanking Interval) section of the National Television System Committee (NTSC) broadcasting signal. The relevant standard is EIA 608.

According to the EIA 608 standard, in the United States, eight types of services that can be transmitted for analog closed caption (analog CC) are shown in Table 1 below.

NTSC Field 1 Line 21 Caption NTSC Field 2 Line 21 Caption CC1 (Main Synchronous Subtitle Service) CC3 (synchronous subtitle service) CC2 (Special Asynchronous Subtitles) CC4 (Special Asynchronous Subtitles) Text1 (First Character Information Service) Text3 (third character information service) Text2 (Second Character Information Service) Text4 (fourth character information service)

For analog captions in the U.S., the user must decide the eight settings as shown in Table 1 above, but since the actual broadcast program does not have information about which of the above eight services is being performed, the caption desired by the user In order to see the service, it was inconvenient to find out what services are provided by constantly changing the settings.

In the case of analog TV broadcasting in Korea, due to the difference between the supported languages as Korean and English, there are some differences in the table and detailed rules regarding the values of actual letters and command sets. The transmission of caption information using the 21st line of the VBI is identical.

Meanwhile, as the broadcasting environment is switched from analog to digital broadcasting, ATSC (Advanced Television System Committee) standard has been established as the terrestrial broadcasting standard in the United States, and for this purpose, digital closed caption (DTVCC), which is reinforced than the conventional analog closed caption, has been established. ) (EIA 708) has been established and used.

1 is a structural diagram of DTVCC caption data in a bit stream of a typical digital television.

As shown here, a bit stream of a digital television is composed of an audio data area, a video data area, and a control data area.

In the case of DTVCC, the caption data itself is transmitted using the user data area included in the header of the picture constituting the video data area, and is in accordance with the MPEG-2 video standard and the ATSC standard. Up to 128 bytes can be transferred to the user data area, and the total data transfer rate cannot exceed 9600bps (bit per second).

In comparison, the analog-closed caption based on EIA 608 is 10 times the bandwidth increase compared to 960bps.

In the case of DTVCC based on EIA 708, a total of 63 caption services can be provided in consideration of the extended bandwidth. Therefore, when the DSCCC is provided in the ATSC standard, a broadcasting station must provide EIT (Event Information) in the Program and System Information Protocol (PSIP). The caption_service_descriptor information must be included in the table or PMT (Program Map Table) so that the digital television receiver knows what kind of DTVCC is included in the program.

As described above, digital captions may be generated in a plurality of digital televisions and displayed using a plurality of caption windows. Therefore, the priority is set in the window so that the window with the lower priority is covered by the window with the higher priority so that the window with the higher priority is actually visible on the screen.

However, when displaying a plurality of windows having the same priority when displaying several windows according to the priorities as described above, there is a problem in that unwanted window is displayed or the desired window is not displayed due to overlapping window areas. .

The present invention was created to solve the above problems, and an object of the present invention is to increase the priority of the current window if the priority is the same while displaying according to the priority when displaying the digital closed caption in a digital television. The present invention provides a caption display method of a digital television that can process and display a window.

In order to achieve the above object, the present invention provides a method for detecting closed caption information included in a bit stream, analyzing the detected closed caption information, and sorting windows according to priorities, and sorting windows according to priorities. When the same priority exists, the step of increasing the priority of the current window and sorting, and displaying the closed caption in accordance with the order of the sorted window.

In the present invention, the current window is a window in which the current caption is displayed.

In the present invention, when the priority is high, it is displayed on the other windows.

According to the present invention, closed captions of the current window currently displayed when there are closed captions having the same priority when sorting a plurality of closed captions in order to display closed captions included in a received bit stream By defining the priority to be sorted with respect to, we define the processing for closed captions with the same priority so that the currently displayed caption is displayed above.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings, and the same parts as in the prior art use the same reference numerals and names. In addition, the present embodiment is not intended to limit the scope of the present invention, but is presented by way of example only and those skilled in the art will be capable of many modifications within the technical spirit of the present invention.

2 is a flowchart illustrating a caption display method of a digital television according to an embodiment of the present invention.

As shown here, first, the closed caption information included in the bit stream is detected (S10).

The detected closed caption information is analyzed to sort windows according to the priority (S20).

At this time, if the same priority exists when sorting windows according to the priority, the priority of the current window is increased (S30) (S40).

In this way, by defining a method for closed captions having the same priority, the currently displayed caption is displayed above.

In this way, the windows are sorted according to the priority and closed captions having the same priority are displayed according to the priority so that the window in which the current caption is displayed is displayed above the captions having the same priority (S50). .

Therefore, the closed caption with the highest priority is displayed on the top screen.

As described above, when the digital closed caption is displayed on the digital television, the present invention has the same priority so that the window can be processed and displayed by increasing the priority of the current window when the priority is the same. It is advantageous to define processing for closed captions so that the currently displayed caption is displayed above and the desired caption is displayed.

Claims (3)

Detecting closed caption information included in the bit stream; Analyzing the detected closed caption information and sorting windows according to priorities; Sorting by raising the priority of the current window if the same priority exists when sorting the windows according to the priority; Displaying the closed captions according to the order of the sorted windows Caption display method of a digital television comprising a. The method of claim 1, wherein the current window is a window in which a current caption is displayed. The caption display method of claim 1, wherein when the priority is high, the display is covered and displayed above other windows.

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