A method of transmitting VBI teletext data

Abstract

The application discloses a transmission method of VBI Teletext data. In the prior art, the demultiplexer directly transmits the extracted data to the Teletex module of the set top box, and the data is easy to be lost. In the method, the VBI Teletext data is transmitted to the set top box through a transport stream data packet, and then the VBI Teletext data is extracted after being demultiplexed by the set top box, is cached to a page cache area, and is transmitted to the Teletex module of the set top box. The Teletex module transmits the graphic text data to a television with graphic text decoding through an analog signal, and the content is displayed after being decoded by the television. The method caches the data, the hardware reads the data from the cache, and the data caching and the hardware reading are operated in parallel, so that the data loss is reduced, and the data integrity is ensured.

Description

Technical Field

[0001] This invention belongs to the field of digital set-top box technology, especially the field of digital set-top box graphic display, and specifically relates to a method for transmitting VBI Teletext data to ensure the integrity of the transmitted VBI Teletext data. Background Technology

[0002] Teletext functionality, also known as image and text functionality, was used in the analog television era to transmit information (such as weather forecasts, lottery numbers, football matches, and team information) by inserting it into the field blanking line of the VBI (Video Interface Block). The television then decoded the information and displayed it on the screen, thus providing users with additional information.

[0003] The vertical blanking interval (VBI), also known as the vertical retrace, is the period used in television programs to insert data into the forward signal. In a 625 / 25 television signal, the usable television lines are lines 6 to 22 and lines 318 to 335, with a maximum of 17 data lines inserted per field.

[0004] In the digital television era, the text and image functionality is retained. Digital text and image information is transmitted to the set-top box via TS Packet (Transport Stream Packet). The set-top box demultiplexes the data to obtain VBI Teletext data, which is then used to generate an analog signal that is transmitted to the television with text and image decoding capabilities. The television decodes the signal and displays the content. The set-top box and the television are connected by a cable, thus ensuring compatibility with the original functionality.

[0005] However, due to differences in set-top box configurations and performance, using a set-top box as a receiving platform to receive digital text and image information also presents the following problems:

[0006] 1. Hardware limitations of the set-top box cause data to be sent to the TV relatively slowly;

[0007] 2. The VBI Teletext data volume of the front-end TS Packet is large and has no upper limit;

[0008] 3. The lack of cached data causes the demultiplexer to directly push the extracted data onto the hardware. These factors lead to data loss when the set-top box transmits data to the TV, resulting in incomplete Teletext content being decoded and displayed by the TV. Summary of the Invention

[0009] The purpose of this invention is to provide a method for transmitting VBI Teletext data under hardware limitations.

[0010] In this invention, VBI Teletext data is transmitted to the set-top box via transport stream data packets. The set-top box then demultiplexes the data to extract the VBI Teletext data, caches it in a page buffer, and transmits the page buffer data to the set-top box's Teletex module. The Teletex module then transmits the text and image data to a television with text and image decoding capabilities via analog signals. The television decodes the data and displays the content. Specifically:

[0011] Step (1) Create two parallel tasks, namely a write task and a read task.

[0012] Step (2) Dynamically create a page cache based on the amount of data. The page cache has real-time storage space that can store the received VBI Teletext data. The writing and reading of the page cache are asynchronous.

[0013] The storage data structure of the page buffer corresponds to the protocol standard of VBI Teletex data. The page buffer stores data in units of pages, and the data stored in a page consists of rows of data. Each page has a maximum of 32 rows of data. When sending data to the Teletext module of the set-top box, it is sent in units of rows.

[0014] Step (3) The write task is as follows: VBI Teletex data is transmitted into the set-top box through the front-end transmission stream, and then the set-top box's demultiplexer filters and extracts the VBI Teletex data; after the write task receives a line of VBI Teletex data from the demultiplexer, it updates or adds the line of data to the page buffer. When a page of data in the buffer is updated, it sends a message to the read task. The message contains the page number, telling the read task that a certain page of data in the page buffer has been updated and that it can read the page of data from the buffer.

[0015] Step (4) The read task is as follows: After receiving the message from the write task, the read task parses out the page number in the message, then reads the data corresponding to the page number from the page cache, and then sends the page data to the Teletex module of the set-top box in fixed rows each time. Finally, the set-top box converts the data into an analog signal and transmits it to the TV.

[0016] Step (5) Repeat steps (3) and (4) until all updated data in the page buffer has been sent to the Teletex module.

[0017] This invention stores the digital image and text data (i.e., VBI Teletext data) extracted by the demultiplexer into the page buffer of DDR (DDR memory), storing it in units of pages. The hardware reads data from this page buffer one page at a time. Furthermore, the writing and reading of the page buffer are asynchronous, ensuring data integrity even if the hardware data transmission is slow while the demultiplexing and filtering extraction is fast. After reading a page of data from the page buffer, a fixed number of rows of data (this fixed value is determined by hardware performance; better performance allows for more rows to be sent each time, thus determining the hardware transmission speed) are sent to the hardware Teletext module. The hardware receives the data, converts it into an analog signal, and transmits it. After sending one page of data, the hardware continues to read the next page from the page buffer, repeating this cycle until all updated pages in the page buffer have been sent.

[0018] The method of this invention prevents the Teletext data extracted by the demultiplexer from being sent directly to the hardware. Instead, the data is cached, and the hardware reads the data from the cache. The data caching and hardware reading are parallel operations, thereby reducing data loss and ensuring data integrity. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the data transmission process in this invention;

[0020] Figure 2 A schematic diagram of the page cache storage structure;

[0021] Figure 3 This is a simplified flowchart of the writing task in this invention;

[0022] Figure 4 This is a simplified flowchart of the reading task in this invention. Detailed Implementation

[0023] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments. It should be noted that the accompanying drawings are for illustrative purposes only and should not be construed as limiting this patent. Furthermore, the present invention can be implemented in various forms and should not be limited to the embodiments described herein. The following embodiments are provided to make the present invention easier to understand and to demonstrate more completely to those skilled in the art.

[0024] like Figure 1As shown, a method for transmitting VBI Teletext data involves transmitting VBI Teletext data (text and image data) to a set-top box via a TS Packet (Transport Stream Packet). The set-top box then demultiplexes the data to extract the text and image data, buffers it in a page buffer, and transmits the page buffer data to the set-top box's Teletex module. The Teletex module then transmits the text and image data to a television with text and image decoding capabilities via analog signals, where the television decodes and displays the content.

[0025] Step (1) Create two parallel tasks, namely a write task and a read task.

[0026] Step (2) dynamically creates a page cache based on the amount of data. The page cache has real-time storage space that can store the received VBI Teletext data. The writing and reading of the page cache are asynchronous, so even if the hardware sends data slowly, the data integrity is ensured.

[0027] like Figure 2 As shown, the storage data structure of the page buffer corresponds to the VBI Teletex data protocol standard. According to the VBI Teletex data protocol standard, a set of VBI Teletex data can contain a maximum of 8 magazines, each magazine can contain a maximum of 100 main pages, some main pages have subpages, that is, a maximum of 800 main pages and an indefinite number of subpages. The page number of the main page ranges from 100 to 899. The page buffer stores data in units of pages, and the data stored in a page consists of rows of data. Each page can contain a maximum of 32 rows of data. When sending data to the Teletext module of the set-top box, it is sent in units of rows. Depending on the hardware performance, a number of rows of data are sent to the Teletext module each time. The better the hardware's data processing performance, the more rows of data are sent each time.

[0028] Step (3) as follows Figure 3 As shown, the write task is as follows: VBI Teletext data is transmitted to the set-top box via the front-end transmission stream, and then the set-top box's demultiplexer filters and extracts the VBI Teletext data. After receiving a line of VBI Teletext data from the demultiplexer, the write task updates or adds the line of data to the page cache. When a page of data in the cache is updated, a message is sent to the read task, which contains the page number, informing the read task that a certain page of data in the page cache has been updated and that it can read the page of data from the cache.

[0029] Step (4) as follows Figure 4As shown, the read task is as follows: after receiving a message from the write task, the read task parses out the page number in the message, then reads the data corresponding to the page with that page number from the page cache, and then sends the page data to the set-top box's Teletex module in fixed rows each time. Finally, the set-top box converts the data into an analog signal and transmits it to the television.

[0030] Step (5) Repeat steps (3) and (4) until all updated data in the page buffer has been sent to the Teletex module.

[0031] The data caching prevents the Teletext data extracted by the demultiplexer from being sent directly to the hardware. Instead, it compensates for hardware limitations by caching, thus ensuring data integrity even if the VBI Teletext data volume is large and the hardware transmission speed is slow.

Claims

1. A method for transmitting VBI Teletext data, characterized in that: VBI Teletext data is transmitted to the set-top box via transport stream data packets. The set-top box then demultiplexes the data and extracts the VBI Teletext data, which is cached in a page buffer and stored in units of pages. The hardware reads data from this page buffer as needed, one page at a time. The writing and reading of the page buffer are asynchronous. The page buffer data is then transmitted to the set-top box's Teletext module. The Teletext module transmits the text and image data to the television with a text and image decoder via analog signals. The television then decodes and displays the content. Specifically: Step (1) Create two parallel tasks, a write task and a read task; Step (2) Dynamically create a page cache based on the amount of data. The page cache has real-time storage space that can store the received VBITeletext data. The writing and reading of the page cache are asynchronous. The storage data structure of the page buffer corresponds to the protocol standard of VBI Teletext data. The page buffer stores data in units of pages, and the data stored in a page consists of rows of data. Each page has a maximum of 32 rows of data. When sending data to the Teletext module of the set-top box, it is sent in units of rows. Depending on the hardware performance, several lines of data are sent to the Teletext module each time. The better the hardware's data processing performance, the more lines of data are sent each time. Step (3) The write task is as follows: VBI Teletext data is transmitted into the set-top box through the front-end transmission stream, and then the set-top box demultiplexer filters and extracts the VBI Teletext data; after the write task receives a line of VBI Teletext data from the demultiplexer, it updates or adds the line of data to the page cache. When a page of data in the cache is updated, it sends a message to the read task. The message contains the page number of the page, telling the read task that a certain page of data in the page cache has been updated and that it can read the page of data from the cache. Step (4) The read task is as follows: After receiving the message from the write task, the read task parses out the page number in the message, then reads the data corresponding to the page number from the page cache, and then sends the page data to the set-top box's Teletext module in fixed rows each time. Finally, the set-top box converts the data into an analog signal and transmits it to the TV. Step (5) Repeat steps (3) and (4) until all updated data in the page buffer has been sent to the Teletext module.

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