KR100250941B1 - The flow control device and method for teletext service of dvb satellite broadcasting receiver - Google Patents

Abstract

PURPOSE: A flow control apparatus and method for teletext service in a DVB(Digital Video Broadcasting) satellite broadcasting receiver is provided to achieve teletext services as well as existing A/V services with minimal supplemental logic using a microprocessor to decode DVBPSI information and SI information. CONSTITUTION: The signal input/output ports of a demultiplexer(10) are connected to the signal input/output ports of a CPU(20) and the signal input/output ports of a teletext queue(31) in a memory part(30). The signal input/output ports of the CPU(20) are connected to the signal input/output ports of a teletext buffer(32) in the memory part(30). The signal output ports of the CPU(20) and the teletext GLUE(40) are connected to the signal input port of a FIFO(50). The signal output port of the FIFO(50) and the signal input/output ports of the teletext GLUE(40) are connected to the signal input/output ports of a video encoder(60).

Description

Flow control apparatus and method for teletext service in DTV satellite receiver

The present invention transcodes teletext data on a DVB stream into an analog television (Pelevision) signal according to a PTS (Presentation Time Stamp) in a satellite broadcasting receiver for digital video broadcasting (hereinafter referred to as DVB). The present invention relates to data flow control in a transcoding system. In particular, when the teletext of an existing TV broadcast is serviced by digital satellite broadcasting, the receiving side transcodes the teletext stream into an analog TV signal in synchronization with video. It is for.

In case of a text broadcasting service in a conventional digital satellite broadcasting receiver, there is a problem of using a MPEG (Moving Pictures Experts Group) demultiplexer having a dedicated text broadcasting decoding hardware or directly manufacturing hardware related thereto.

An object of the present invention is to solve the above-mentioned conventional problems. In particular, a digital satellite receiver basically controls a NIM, an MPEG demultiplexer, an MPEG A / V (Audio / Video) decoder, an analog video decoder, and various chips. And a satellite receiver for DVB to enable text broadcasting services as well as conventional A / V with minimal additional logic using a microprocessor, including a general purpose microprocessor for decoding DVBPSI or SI information. The present invention provides a flow control apparatus and method for text services.

In order to achieve the above object, a flow control apparatus for teletext service in a satellite broadcasting receiver for DVB according to the present invention includes a demultiplexer for demultiplexing a DVB signal; A central processing unit responsible for preparing and transmitting data to be transcoded into a next field within one field signal time, and for informing a video encoder of a vertical blanking interval (hereinafter referred to as VBI) line to use; A portion of a buffer for demultiplexing, and a memory portion capable of reading and writing used to store program codes, variables, and the like; It can be implemented as a general EPLD (Electrically Programmable Logic Device), and receives the field signal from the video encoder, passes the delay as much as VBI, generates an interrupt, and then processes the interrupt acknowledgment from the central processing unit. And a teletext GLUE divided into a portion generating a 6.9375MHz TTX _- CLK using a 27MHz clock, and a DMA portion for reducing the processor overhead when transferring data from the CPU buffer to the FIFO; A FIFO which temporarily stores data in order to transmit the data stored in the buffer of the central processing unit to the video encoder; The technical configuration is characterized by including a video encoder for outputting an analog video signal by formatting the data input as a digital signal into an analog signal.

Meanwhile, in the flow control method for the teletext service in the DVB satellite broadcasting receiver, the data processing is repeated at a cycle of 46 bytes at a PES (Packetized Elementary Stream) level until the processing of one field of data is completed. Repeated, the first step of looking at the first 3 bytes of the 46 bytes; A second step of comparing and judging whether the three-byte data block in the first step is a header or a Teletext ES (Elementary Stream); A third step of comparing and determining whether the data block is a header in the second step if the data block conforms to a specification; A fourth step of returning if it does not meet the rule in the third step, and determining whether it is a stuffing block if the text is conforming to the rule; In the fourth step, if the stuffing block is omitted, go to the seventh step of skipping 46 bytes immediately, and if the stuffing block is not the stuffing block in the fourth step, determine whether to convert the content of one field. Steps; A sixth step of transmitting data of the demultiplexer queue to a buffer of the central processing unit when the contents of the field are not changed in the fifth step; A seventh step of jumping over 46 bytes of data; An eighth step of transmitting data of the CPU buffer to the FIFO and the video encoder when the content of the field is changed in the fifth step; A ninth step of determining whether a PTS exists when the first 3 byte data is a header in the first step; A tenth step of returning to the seventh step if the PTS does not exist in the ninth step, and determining whether the PTS is on time if the PTS exists; In the tenth step, if the PTS is not on time, the method returns. If the PTS is on time, the method returns to the seventh step to process data.

The flow control apparatus and method for the teletext service in the DVB satellite broadcasting receiver of the present invention is operated to enable the text broadcasting service as well as the existing A / V with the minimum additional logic, and thus, the digital satellite as in the conventional analog TV broadcasting. In the case of teletext broadcasting in a broadcast, the receiver has an effect of implementing a text broadcasting service conforming to the standard by transcoding into a teletext decoding and an analog TV signal conforming to the broadcast standard.

1 is a block diagram of a system-wide input and output of the present invention;

2 is a control flowchart of the present invention.

3 is a diagram showing the structure of data;

4 is an interrupt timing diagram and a transcoding timing diagram.

<Description of the symbols for the main parts of the drawings>

10: demultiplexer 20: central control unit

30: memory unit 31: teletext queue

32: teletext buffer 40: teletext GLUE

50: FIFO 60: Video Encoder

Hereinafter, the configuration and operation of the flow control apparatus and method for teletext service in the DVB satellite broadcasting receiver according to the present invention will be described in detail with reference to the accompanying drawings.

<Example>

As shown in FIG. 1, the signal input / output terminal of the demultiplexer 10 is connected to the signal input / output terminal of the central processing unit 20 and the teletext queue 31 of the memory unit 30, and the central processing unit 20 is connected. Is connected to the signal input / output terminal of the teletext buffer 32 of the memory unit 30, and the signal input / output terminal of the central processing unit 30 is connected to the signal input / output terminal of the teletext GLUE 40. The signal output terminal of the central processing unit 20 and the signal output terminal of the teletext GLUE 40 are connected to the signal input terminal of the FIFO 50, and the signal output terminal and the teletext GLUE 40 of the FIFO 50 are connected. This embodiment is constructed by connecting a signal input / output terminal to the signal input / output terminal of the video encoder 60.

Hereinafter, an embodiment of the present invention configured as described above will be described.

First, an interrupt based method corresponding to one field from the video encoder 60 is generated after the VBI of the field signal.

When the teletext request, the field signal, and the H sync signal are applied to the teletext GLUE 50 by the video encoder 60, the teletext GLUE 50 requests the field signal and the teletext interrupt to the central processing unit 20. Done.

Then, the data input through the demultiplexer 10 and stored in the memory unit 30 outputs the data to the FIFO 50 when an interrupt is applied to the central processing unit 20, and the central processing unit 20 A signal for confirming that the teletext interrupt has been received by the teletext GLUE 40 is output, and a reset signal is applied to the FIFO 50.

In the teletext GLUE 40, a reset signal and a teletext clock are applied to the FIFO 50. In the FIFO 50, data stored according to the signal of the teletext GLUE 40 is stored in the video encoder 60. Will output

The structure of the data is shown in FIG. 3, and the movement of the data is transmitted from the demultiplexer queue 10 to the memory unit 30 of the central processing unit 20 and back to the FIFO 50.

In order to extract teletext data, PES to ES level must be checked and stuffing bytes must be filtered. Therefore, the data to be transcoded remains in the central processing unit 20 buffer until one field is reached, and one field data exists. When the data is filled, it is transmitted to the FIFO 50 through DMA transfer. The data existing in the FIFO 50 is exactly one line according to the clock generated by the teletext GLUE 40 when the video encoder 60 makes a data request. Each portion is supplied to the video encoder 60 in a serial bit stream.

4 shows an interrupt timing diagram, which is a timing diagram during interrupt generation and processing, and a transcoding timing diagram, which is a transmission timing diagram of a serial bitstream when there is a data request from a video encoder. The serial data of the prepared FIFO 50 is transmitted to the video encoder 60 during VBI, ② section is interrupt initialization time, ③ section is time to prepare data of the next field, and ④ section is at section ③. When all data corresponding to one field is extracted, it is the time to DMA transfer the data to FIFO 50. ⑤ section is the time to set the VBI line and the number of data to be transcoded into the next field in the video encoder 60. .

The intervals 3 to 5 are the execution time of the interrupt service routine.

As described above, the flow control apparatus and method for the teletext service in the DVB satellite broadcasting receiver of the present invention, in particular, when the teletext broadcasting is performed in digital satellite broadcasting as in the conventional analog TV broadcasting, It is effective to implement the character broadcasting service that conforms to the standard by transcoding into the corresponding teletext decoding and analog TV signal.

Claims (2)

A demultiplexer for demultiplexing the DVB signal; A central processing unit responsible for preparing and transmitting data to be transcoded into the next field within one field signal time and informing the video encoder of the VBI line to be used; A part of a buffer for demultiplexing, and a read and write memory unit for storing program codes, variables, and the like; It can be implemented as a general EPLD. After receiving the field signal from the video encoder, it passes the delay as much as VBI, generates interrupts, and processes the IACK from the central processing unit again. 6.9375MHz TTX using 27MHz clock. _A teletext GLUE divided into a CLK generation portion and a DMA portion to reduce the CPU overhead when transferring data from the CPU buffer to the FIFO; A FIFO which temporarily stores data in order to transmit the data stored in the buffer of the central processing unit to the video encoder; And a video encoder for outputting an analog video signal by formatting the data inputted as a digital signal into an analog signal. The flow control apparatus for the teletext service in a DVB satellite broadcasting receiver. The data processing is repeated at the PES level with a period of 46 bytes, and is repeated until processing of one field amount of data is finished, the first step of looking up the first 3 bytes of the 46 bytes; A second step of judging whether the three-byte data block in the first step is a header or a teletext ES; A third step of comparing and determining whether the data block is a header in the second step if the data block conforms to a specification; A fourth step of returning if it does not meet the rule in the third step, and determining whether it is a stuffing block if the text is conforming to the rule; In the fourth step, if the stuffing block is omitted, go to the seventh step of skipping 46 bytes immediately, and if the stuffing block is not the stuffing block in the fourth step, determine whether to convert the content of one field. Steps; A sixth step of transmitting data of the demultiplexer queue to a buffer of the central processing unit when the contents of the field are not changed in the fifth step; A seventh step of jumping over 46 bytes of data; An eighth step of transmitting data of the CPU buffer to the FIFO and the video encoder when the content of the field is changed in the fifth step; A ninth step of determining whether a PTS exists when the first 3 byte data is a header in the first step; A tenth step of returning to the seventh step if the PTS does not exist in the ninth step, and determining whether the PTS is on time if the PTS exists; In the tenth step, if the PTS is not on time, the PTS returns. If the PTS is on time, the control returns to the seventh step to process the data. Way.

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