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> Define events in EIT
Jimmy Tran
post Apr 30 2012, 08:13 PM
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Hi all,

I am trying to write an EPG server but I have some questions with the definitions of events for our system:

1. Can I put more than 8 events in a segment (which includes 8 sections)? Because I'm understanding that each event only can be defined with only 1 section.

2. I'm confused with last_section_number and segment_last_section_number when I try to define events.
Example: I have 3 events in EIT actual schedule table.

1st: Run from 02:00 to 02:30 (it will have to be in segment #0 with sections 0-7)
2nd: Run from 02:30 to 03:00 (it will have to be in segment #0 with sections 0-7)
3rd: Run from 06:30 to 07:00 (it will have to be in segment #2 with sections 16-23)

I had defined them as below:
* 1st
- section_number = 0
- last_section_number = 16
- segment_last_section_number = 1

* 2nd
- section_number = 1
- last_section_number = 16
- segment_last_section_number = 1

* 3rd
- section_number = 16
- last_section_number = 16
- segment_last_section_number = 16


I think these definitions is OK, but the EIT actual schedule table cannot be recorgnised when I use Stream Expert to analyze.

But when I try to re-define them as below, it works. Of course this definition is not correct what I've read from DVB documents.
* 1st
- section_number = 0
- last_section_number = 1
- segment_last_section_number = 1

* 2nd
- section_number = 1
- last_section_number = 1
- segment_last_section_number = 1

* 3rd
- section_number = 16
- last_section_number = 16
- segment_last_section_number = 16


Can anyone tell me why?

Thanks and regards,
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Jomu
post Sep 19 2012, 06:03 PM
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QUOTE (Jimmy Tran @ Apr 30 2012, 12:13 PM) *
1. Can I put more than 8 events in a segment (which includes 8 sections)? Because I'm understanding that each event only can be defined with only 1 section.

2. I'm confused with last_section_number and segment_last_section_number when I try to define events.
Example: I have 3 events in EIT actual schedule table.


I am not too competent a source, but as per my reading of it, I think you need to fill "holes" in your second situation. Sections from segment can be empty, but they must be sent, IMHO.

As per first question, I saw nothing in spec limiting number of events per segment (ie 3-hour interval). Only important prohibition there is not to split one event_item over two sections.

The best way is to check with ts_101211 again. Page 15:
QUOTE
if only n < 8 sections of a segment are used, the information shall be placed in the first n sections of the segment. To signal that the last sections of the segment are not used, the value s0 + n - 1, where s0 is the first section number of the segment, shall be encoded in the field segment_last_section_number of the EIT header. As an example, if segment 2 contains only 2 sections, the field segment_last_section_number shall contain the value 8 + 2 - 1 = 9 in those two sections;
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