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MPE and DSMCC section_length



Hallo,

 

I plan to write DVB/IP gateway and I have question related to meaning of the section_length field within DSMCC section.

 

Based on specs, it is defined as follows:

 

dsmcc_section_length -- This 12 bit field specifies the number of remaining bytes in the DSMCC_section immediately following this field up to the end of the dsmcc_section. The value in this field shall not exceed 4093 (indicating a section maximum data length of 4084 bytes, following the last_section_number field and up to the CRC_32/checksum field).

 

There is also one “example” saying

 

else if (table_id == 0x3E) {

 

                        for (i=0;i<dsmcc_section_length-9;i++) {

 

                                    private_data_byte

 

                        }

.

 

I have grabbed some TS packets, please see attached word document. Based on this data, third packet within data, section_length = 0x463 = 1134. Data are included in the 6x188 TS packets. This makes 6x188 = 1128 bytes.  I am not able to find relation between those numbers and specs.

 

Could you, please, someone explain?

 

How is it with CRC, where is it within those packets?

 

Thank you in advance.

 

Regards, Daniel

 

Attachment: PID0xA28.doc
Description: PID0xA28.doc