JP2005073286A - System for validating section data correctness, and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a system for validating section data correctness, of which the section syntax directions are 0 in a system which verifies the correctness of a private section based on a section format of ISO/IEC Provision 13818-1, and which can perform a CRC check, without applying load to a CPU in a private section as which CRC was specified. <P>SOLUTION: A decision is made as to whether CRC is given to the private section concerned, by investigating a section syntax directions field or a table-identifying field of an inputted private section, outputs only what has checked correctness from result of CRC operation regarding what is given, and outputs as what has checked correctness regarding what is not given. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a section data validity checking apparatus and method for inputting a private section based on a section format defined in ISO / IEC 13818-1 and checking the validity of the section data.

  Conventionally, private data is transport streamed in ISO / IEC 13818-1 (MPEG2 system) by ISO / IEC (International Organization for Standadization / International Electrotechnical Commission). When transmitting by packet, it is stipulated that the private data be transmitted as a private section of section format data. Also, two types of private section syntax are defined for the private section, and these are distinguished depending on whether the section_syntax_indicator field is 0 or 1. That is, CRC_32 (CRC, Cyclic Redundancy Check) is assigned to the private section whose section syntax instruction field is 1, and the validity of the data in the private section can be confirmed. On the other hand, if the section syntax instruction field in the private section is 0, CRC is not defined in the private section.

  By the way, in the download transmission standard of the Association of Radio Industries and Businesses (ARIB) recently, in the section of the software body to be downloaded, which is described based on the section format of ISO / IEC 13818-1 It has been determined that CRC_32 is added to the end of the code_data_byte (downloaded software) field while the syntax instruction field is always set to 0 (Non-patent Document 2).

  In addition, due to the ease of data handling, etc., there is a high level of versatility in private sections with a section syntax instruction of 0, and it is natural that reliability is required in the private section. It is assumed that CRC is assigned to a private section whose section syntax instruction is 0.

In such a private section, even if the section syntax instruction field is 0, data reliability can be ensured.
“IS / 138138-1 (Syntax of the Private section)”, International Organization for Standardization / International Electro-Technical Commission (International Organization for Standadization / International Electrotechnical Commission), 1994 “CS Digital Broadcast Standard Shared Receiver (ARIB STD-B16)”, Version 1.0, The Japan Radio Industry Association, October 7, 1997, p12-15

  However, since the conventional apparatus does not assume the case where CRC_32 is assigned to a private section whose section syntax indication field is 0, the private section where the value of the section syntax indication field is 0 and CRC_32 is assigned is assumed. Even if is input, the CRC operation cannot be performed by the CRC operation unit as in the private section whose section syntax instruction field is 1, and has to be performed by software. In this case, there is a problem that a load is applied to the CPU.

  The present invention has been made in view of such conventional problems. In an apparatus for confirming the validity of a private section based on the section format defined in ISO / IEC 13818-1, the section syntax instruction is 0. An object of the present invention is to provide a section data validity confirmation device capable of performing a CRC check on a private section with a defined CRC without imposing a load on the CPU.

  In order to solve the above-described problems, a section data validity checking device according to the present invention is provided with CRC calculation means for performing CRC calculation of input section data, a buffer for storing the input section data, and input section data to which CRC is assigned. The first syntax discrimination means for discriminating whether or not it conforms to ISO / IEC 13818-1 and when the CRC is determined not to be assigned by the first syntax discrimination means other than ISO / IEC 13818-1 And a second syntax discrimination means for judging whether or not a CRC is assigned according to the standard.

  With this configuration, it is first determined whether CRC has been added to the input section data based on the determination results of the first and second syntax determination means. If the input section data has no CRC, or has a CRC, if the validity can be confirmed from the calculation result of the CRC calculation means, the input section data in the buffer is output, and in other cases By deleting the input section data, only the section data whose validity has been confirmed can be advanced to the next process.

  The section data validity checking method of the present invention includes a first syntax determination step for determining whether CRC is added to input section data according to the ISO / IEC 13818-1 standard, and the first syntax determination step. When it is determined that the CRC is not assigned in step 2, a second syntax determination step for determining whether the CRC is assigned according to a standard other than the ISO / IEC 13818-1 standard, and CRC calculation of the input section data are performed. CRC calculation step, and when the first syntax determination step and the second syntax determination step determine that there is no CRC, and when it is determined that CRC is included in the second syntax determination step, the CRC calculation step A determination step of determining that the input section data is correct.

  Thereby, it is first determined from the determination results of the first and second syntax determination steps whether CRC has been assigned to the input section data. If the input section data does not have a CRC or has a CRC, the input section data can be determined to be correct if the calculation result in the CRC calculation step is correct.

  According to the section data validity checking device according to the present invention, a private section is input based on section formation defined in ISO / IEC 13818-1, and when the value of the section syntax indication field is 0 in the private section, the table Checks whether the private section has a CRC according to the value of the identification field. If the CRC is added, the CRC calculation result is output. If the CRC is not added, the calculation indicates that the calculation is valid without considering the calculation result. The result is output, and the private section is selected and output only when the input private section is valid according to these operation results. Therefore, the value of the section syntax instruction field is 0, A private section with a CRC is entered. Even if there is an effect that it is possible to perform a CRC check without burdening the CPU. In addition, the external storage area that is stored until the private section is used requires a CRC check by the CPU, and private sections that have not been validated are not output. Since only the private section that cannot be confirmed is output, there is an effect of reducing unnecessary data transfer. Further, since a program for CRC check is not required in software, there is an effect that software creation becomes easy.

(Embodiment 1)
FIG. 1 is a block diagram showing a configuration of a section data validity checking device according to the first embodiment.

  In the figure, reference numeral 1 denotes a private section input pin, which inputs private section data based on a section format stipulated by ISO / IEC 13818-1 before validity confirmation and outputs it to each processing means. Reference numeral 2 denotes a syntax determination circuit, which extracts the value of the section_syntax_indicator (section syntax instruction) field of the private section from the private section data input from the private section input pin 1 and outputs it together with the private section. A CRC calculator 3 performs a CRC calculation on the private section data input from the private section input pin 1 and outputs the calculation result. 4 is a table identification filter, which receives the output of the syntax discrimination circuit 2 and extracts table_id (table identification) from the input private section data if the value is 0 according to the value of the input section syntax instruction field. If the value is 1, the table identification is not extracted and is not output. Reference numeral 5 denotes a CRC selector which inputs the operation result from the CRC calculator 3 and the value of the section syntax instruction field from the syntax discriminating circuit 2 and switches the output depending on the case where the value is 0 or 1, Output the calculation result. 6 is a table identification checker, which stores a plurality of table identifications in advance, and calculates when the table identification extracted by the table identification filter 4 and the value of the section syntax instruction field output from the CRC selector 5 are zero. When the result is input and the input table identification matches one of the pre-stored table identifications, the calculation result is output as it is, and when the result does not match, the CRC calculation ends correctly without considering the calculation result. A signal to that effect is output. Reference numeral 7 denotes a buffer management circuit, which is an operation result output from the CRC selector 5 when the value of the section syntax instruction field is 1, or a signal output from the table identification checker 6 when the value of the section syntax instruction field is 0 To confirm the validity of the private section from these inputs, and if it can be confirmed, the retained private section will be output, while if it cannot be confirmed, the private section will be deleted. To instruct. A buffer 8 temporarily holds private section data input from the private section input pin 1 and erases or outputs the private section data according to an instruction from the buffer management circuit 7. A private section output pin 9 outputs private section data from the buffer 8.

  Here, the private section whose section syntax indication field value is 0 or 1 is hereinafter referred to as a short section or a long section, respectively.

  FIG. 2 is a diagram showing an example of the data structure of the private section input to the private section input pin of FIG.

  In the figure, 11 is table_id (table identification), which defines a private table to which the private section belongs. Note that some of the table identifications are defined by ISO, and some are defined by the ARIB standard.

  Reference numeral 12 denotes a section_syntax_indicator (section syntax instruction), which is a 1-bit field that defines two types of private section syntax by 0 or 1. Reference numeral 13 denotes CRC_32 (CRC), which is a 32-bit field and represents the CRC value for the entire private section. In this data structure, if the value of the section syntax instruction field is 0, the private section is a short section with CRC, and if the value is 1, it is a long section. As described in the related art, there is a short section in the private section where the value of the section syntax instruction field is 0 and CRC_32 is not added in the data structure. The short section is hereinafter referred to as a CRC-less short section.

  Therefore, the private section input pin 1 (FIG. 1) receives three types of private sections: a long section, a short section with CRC, and a short section without CRC.

FIG. 3 is a block diagram showing in detail a configuration example of the table identification checker of FIG.
In the figure, reference numeral 21 denotes a table identification memory, which stores the table identification of the short section with CRC. As described above, the table identification defines the private table to which the private section belongs, and the three types of private sections do not belong to the same private table. Therefore, the three types of private sections have different table identifications. Have. That is, the table identification stored in the table identification memory 21 is unique to the short section with CRC. Reference numeral 22 denotes a comparator which inputs a table identification output from the table identification filter 4 and compares the input table identification with a plurality of table identifications stored in the table identification memory 21 to find a matching table identification. If there is no matching table identification, a signal indicating that there is a mismatch is output. Reference numeral 23 denotes a comparison result storage circuit which inputs a signal from the comparator 22 and stores and outputs “match (1)” or “mismatch (0)”. Reference numeral 24 denotes a determination circuit, which is an operation result from the CRC selector 5 (“error (1)” or “no error (0)”), and “match (1)” or “mismatch (0) from the comparison result storage circuit 23. ) ", And when" Match (1) "and" Error (1) "are input," No validity (1) "is output, and" Match (1) "and" No error (0) "are output. When it is input, or when “mismatch (0)” is input regardless of the calculation result, “with validity (0)” is output.

  FIG. 4 is a flowchart showing the operation of the section data validity checking apparatus according to the first embodiment of the present invention.

Next, the operation of the section data validity checking apparatus configured as described above will be described with reference to FIGS.
Here, as described above, since the private section input pin 1 is input with three types of private sections, a long section, a short section with CRC, and a short section without CRC, the operation will be described separately for these types. To do.

First, a case where a long section is input will be described.
The data of the long section before the validity check is input to the private section input pin 1 (S1), and is output to the buffer 8, the CRC calculator 3, and the syntax determination circuit 2. The buffer 8 temporarily holds long section data input from the private section input pin 1. The CRC calculator 3 performs CRC calculation on the long section data input from the private section input pin 1 and outputs the calculation result (S2). The syntax determination circuit 2 extracts and outputs the value of the section syntax instruction field of the long section from the long section input from the private section input pin 1 (S3).

  Next, the CRC selector 5 inputs the value (S4) of the section syntax instruction field from the syntax discriminating circuit 2 and the calculation result from the CRC calculator 3, and the output selected when section_syntax_indicator is 1 based on the value. And the calculation result is output. At this time, the table identification filter 4 receives the value (S4) of the section syntax instruction field from the syntax determination circuit 2, and extracts table_id (table identification) from the long section based on the value (1). No output.

  Next, the buffer management circuit 7 inputs the calculation result output from the CRC selector 5, confirms the validity of the long section from the calculation result (S7), and the calculation result is “no error”. If it can be confirmed that “it is valid”, the long section held in the buffer 8 is output. On the other hand, if it is determined that the calculation result is “error” and “no validity”, the long section is deleted. In this way, each buffer 8 is instructed. In accordance with an instruction from the buffer management circuit 7, the buffer 8 erases the temporarily stored data of the long section or outputs it from the private section output pin 9.

Next, a case where a short section with CRC is input will be described.
The data of the CRC-added short section before the validity check is input to the private section input pin 1 (S1), and is output to the buffer 8, the CRC calculator 3, and the syntax determination circuit 2. The buffer 8 temporarily holds the data of the CRC-added short section input from the private section input pin 1.

  The CRC calculator 3 performs a CRC calculation on the CRC-added short section data input from the private section input pin 1 and outputs the calculation result (S2). Further, the syntax determination circuit 2 extracts and outputs the value of the section syntax instruction field of the short section with CRC input from the short section with CRC input from the private section input pin 1 (S3).

  Next, the CRC selector 5 inputs the calculation result from the CRC calculator 3 and the value (S4) of the section syntax instruction field from the syntax determination circuit 2, and when section_syntax_indicator is 0 based on the value (0). Switch to the selected output and output the calculation result. At this time, the table identification filter 4 inputs the value (S4) of the section syntax instruction field from the syntax discrimination circuit 2, and based on the value (0), the table_id (table identification) of the CRC-added short session 9 is obtained. Extract and output (S5).

  Next, in the table identification checker 6, table identifications of a plurality of short sections with CRC are stored in the table identification memory 21 in advance, and the comparator 22 extracts the table identification extracted and input by the table identification filter 4 into the table identification memory. In this case, since there is a matching table identification, a signal to the effect of matching is output (S6). The comparison result storage circuit 23 receives the signal from the comparator 22, stores “match (1)”, and outputs it. Then, the determination circuit 24 inputs “match (1)” from the comparison result storage circuit 23 and the operation result (“error (1)” or “no error (0)”) from the CRC selector 5, and If the calculation result is “error (1)”, “no validity (1)” is obtained from “match (1)” and “error (1)”, and the calculation result is “no error (0)”. For example, “with validity (0)” is output from “match (1)” and “no error (0)” (S7).

  Next, the buffer management circuit 7 inputs the output from the determination circuit 24 of the table identification checker 6, confirms the validity of the short section with CRC from the input, and can confirm that the input is “valid”. Each of the buffers 8 is instructed to output the short section with CRC held in the buffer 8 and to delete the short section if the input is “invalid”. In accordance with an instruction from the buffer management circuit 7, the buffer 8 erases the data of the short section with CRC temporarily stored (S8) or outputs it from the private section output pin 9 (S9).

Finally, the case where a short section without CRC is input will be described.
The data of the short section without CRC before the validity check is input to the private section input pin 1 (S1), and is output to the buffer 8, the CRC calculator 3, and the syntax determination circuit 2. The buffer 8 temporarily holds data of the short section without CRC input from the private section input pin 1.

  The CRC calculator 3 performs CRC calculation on the short section data without CRC input from the private section input pin 1 and outputs the calculation result (random calculation result) (S2). The syntax determination circuit 2 extracts and outputs the value of the section syntax instruction field of the short section without CRC from the short section without CRC input from the private section input pin 1 (S3).

  Next, the CRC selector 5 inputs the calculation result from the CRC calculator 3 and the value (S4) of the section syntax instruction field from the syntax determination circuit 2, and when section_syntax_indicator is 0 based on the value (0). Switch to the selected output and output the calculation result. At this time, the table identification filter 4 inputs the value (S4) of the section syntax instruction field from the syntax determination circuit 2, extracts the table identification of the CRC-added short section based on the value (0), and outputs it. (S5).

  Next, in the table identification checker 6, table identifications of a plurality of short sections with CRC are stored in the table identification memory 21 in advance, and the comparator 22 extracts the table identification extracted and input by the table identification filter 4 into the table identification memory. In this case, since there is no matching table identification, a signal indicating that they do not match is output (S6). The comparison result storage circuit 23 receives the signal from the comparator 22 and stores and outputs “mismatch (0)”. Then, the determination circuit 24 inputs “mismatch (0)” from the comparison result storage circuit 23 and the calculation result (random calculation result) from the CRC selector 5, and “mismatch (0)” is input. “With legitimacy (0)” is output on the assumption that the CRC calculation is correctly completed without considering the calculation result.

  Next, the buffer management circuit 7 inputs the output from the determination circuit 24 of the table identification checker 6, confirms the validity of the short section without CRC from the input (S7), and actually confirms the validity. However, it is instructed to output the CRC-free short section held in the buffer 8 in response to the “valid” input. The buffer 8 outputs the CRC-free short section data temporarily held from the private section output pin 9 in accordance with the instruction from the buffer management circuit 7 (S9).

  As described above, in the section data validity checking device according to Embodiment 1 of the present invention, when a short section is input, it is checked whether or not the short section has a CRC according to the value of the table identification field. If so, the CRC calculation result is output, and if the CRC is not included, the calculation result indicating that the calculation result is valid without considering the calculation result is output, and the input short section is valid according to these calculation results. Only when the short section is selected and output, the CRC check can be performed without imposing a load on the CPU even when the short section with CRC is input. Also, the external storage area that is stored until the private section is used requires a CRC check by the CPU, and a private section whose validity has not been confirmed is not output and the validity has been confirmed, or Since only the private section that cannot be confirmed by the CPU is output, unnecessary data transfer is reduced. Further, since the CRC check program is not required in software, software creation is facilitated.

  The present invention is useful as an apparatus or method for confirming the validity of a private section based on the section format defined in ISO / IEC 13818-1.

It is a block diagram which shows the structure of the section data correctness confirmation apparatus by Embodiment 1 of this invention. It is a data structure figure which shows an example of the short section with CRC input into the private section input pin of FIG. It is a block diagram which shows the structural example of the table identification checker of FIG. 1 in detail. It is a flowchart figure which shows the operation | movement in the section data correctness confirmation apparatus by Embodiment 1 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Private section input pin 2 Syntax discriminating circuit 3 CRC calculator 4 Table identification filter 5 CRC selector 6 Table identification checker 7 Buffer management circuit 8 Buffer 9 Private section output pin 11 table_id
12 section_syntax_indicator
13 CRC_32
21 Table identification memory 22 Comparator 23 Comparison result storage circuit 24 Determination circuit

Claims (7)

CRC calculation means for performing CRC calculation of input section data;
A buffer for storing input section data;
First syntax discrimination means for discriminating whether or not CRC is given to the input section data according to the ISO / IEC 13818-1 standard;
A second syntax determination means for determining whether a CRC is provided according to a standard other than the ISO / IEC 13818-1 standard when the first syntax determination means determines that no CRC is provided;
If the input section data does not have a CRC, or if the input section data has a CRC, if the validity can be confirmed from the calculation result of the CRC calculation means according to the determination results of the first and second syntax determination means, the buffer A buffer management means for instructing to output the input section data within, and erasing the input section data in other cases,
A section data correctness confirmation device. In the section data validity checking device according to claim 1,
The second syntax discrimination means is:
Identifier filter means for extracting an identifier representing the data type of the input section data;
Identifier storage means for storing a plurality (including one) of identifiers of sections to which CRC is attached;
Identifier comparison means for comparing the identifier of the input section data extracted by the identifier filter means with all identifiers stored in the identifier storage means,
In the identifier comparing means, if the identifier output from the identifier filter means is detected to match at least one of the plurality of identifiers stored in the identifier storage means, it is determined that the identifier is attached. Section data validity check device. A first syntax determination step for determining whether or not CRC is added to the input section data according to the ISO / IEC 13818-1 standard;
A second syntax determination step for determining whether a CRC is provided according to a standard other than the ISO / IEC 13818-1 standard when it is determined that no CRC is assigned in the first syntax determination step;
CRC calculation step for performing CRC calculation of input section data;
If it is determined that there is no CRC in the first syntax determination step and the second syntax determination step, and if it is determined that CRC is included in the second syntax determination step, the calculation result of the CRC calculation step is correct. A determination step for determining that the input section data is correct;
A method for confirming the validity of section data. In the section data validity confirmation method according to claim 3,
A section data validity checking method, wherein at least one of the CRC calculation step and the first syntax determination step or the second syntax determination step operates in parallel. In the section data validity confirmation method according to claim 3,
The second syntax determination step includes
An identifier filter step for extracting an identifier representing the data type of the input section data;
An identifier comparison step for comparing the identifier of the input section data extracted in the identifier filter step with a plurality of (including one) identifiers with CRC stored in advance.
In the identifier comparison step, if the identifier output from the identifier filter step is detected to match at least one of a plurality of identifiers stored in advance, the section is determined to have a CRC. Data validity check method. A section data validity checking device that inputs a private section based on the section format defined in ISO / IEC 13818-1 and checks and outputs the validity of the private section.
CRC calculation means for inputting the private section and performing CRC calculation of the private section;
CRC selector means for switching the output in accordance with the value of the section syntax instruction field of the input private section and outputting the operation result from the CRC operation means;
When the value of the section syntax indication field is 0, the calculation result from the CRC selector is input, and based on the value of the input private section table identification field, it is checked whether or not the private section has a CRC. CRC calculation result masking means for outputting the calculation result if it is attached, and outputting a signal indicating that the calculation result is valid without considering the calculation result if CRC is not attached,
When the value of the section syntax instruction field is 1, a signal indicating that there is an operation result or validity from the CRC selector, and when the value of the section syntax instruction field is 0, from the CRC operation result masking means. And whether or not the input private section is valid according to the obtained result, and only when the validity is valid, a valid private section selection means for selecting and outputting the private section. A section data validity checking device characterized by comprising: In the section data validity confirmation device according to claim 6,
A syntax determination means for inputting the private section and extracting the value of the section syntax instruction field of the private section;
Table identification filter means for extracting a table identification field from the input private section when the value of the section syntax instruction field extracted by the syntax determination means is 0;
A data delay means for temporarily storing the private section until the private section is input and the operation for confirming the validity of the private section is completed,
The CRC selector means obtains the value of the section syntax instruction field extracted by the syntax judgment means from the syntax judgment means,
The CRC calculation result mask means checks whether the table identification field input from the table identification filter means matches at least one table identification entry of a private section with CRC that has been set in advance. Is to confirm that it has a CRC,
The valid private section selection means outputs the private section regarding the private section temporarily stored in the data delay means when the validity is confirmed, and erases the private section when the validity cannot be confirmed. Section data validity checking device characterized by being a thing.

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