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> How to Differentiate EIT Actual Present/Follwoing, EIT Actual Present/Follwoing
dvbfreaky007
post Apr 29 2010, 10:15 PM
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Hi,
How to differentiate EIT Actual Present/Following, to be specific "Present" data and "following" data.

in DVB
0x4E is the table id for Actual TS Present or Followoing , which means EIT Section data with Table id of 0x4E is carrying Actual Present/Following Event Info.

Say take one service id of : 0x2044 , for this service id,
How to differentiate Present Event Information and Following Information of above mentioned Service ID.

Any Idea?
are there any flags to differentiate between "Present Event Info and Following Event Info"?
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pclare
post May 9 2010, 09:15 PM
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QUOTE (dvbfreaky007 @ Apr 29 2010, 12:15 PM) *
How to differentiate EIT Actual Present/Following, to be specific "Present" data and "following" data.


The obvious thing to do is compare timestamps. The following event will always have a start time greater than that of the present event.
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Edsam
post Jul 1 2010, 07:19 PM
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>>>How to differentiate EIT Actual Present/Following, to be specific "Present" data and "following" data.

If "section_number= 0x00", means "Present" data .
If "section_number= 0x01", means "following" data .
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pclare
post Jul 2 2010, 05:46 AM
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QUOTE (Edsam @ Jul 1 2010, 09:19 AM) *
>>>How to differentiate EIT Actual Present/Following, to be specific "Present" data and "following" data.

If "section_number= 0x00", means "Present" data .
If "section_number= 0x01", means "following" data .


That may be the case in your data but there is nothing in the DVB specification that enforces this. In general (for any of the tables) you shouldn't attach any meaning to the section number. If you want a general solution that works for all broadcasters in all territories then I would strongly suggest that you do not use the section number to distinguish between present and following events.
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Edsam
post Jul 2 2010, 05:56 PM
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QUOTE (pclare @ Jul 2 2010, 06:46 AM) *
That may be the case in your data but there is nothing in the DVB specification that enforces this. In general (for any of the tables) you shouldn't attach any meaning to the section number. If you want a general solution that works for all broadcasters in all territories then I would strongly suggest that you do not use the section number to distinguish between present and following events.


I don't think so. In DVB specification, for EIT present\following table, the table_id 0x4e(actual)or 0x4f(other), and the first section is for present event, the second one is for fellowing event. You could look 300468 file . The eit event is list by time, sorted!
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pclare
post Jul 14 2010, 05:00 AM
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QUOTE (Edsam @ Jul 2 2010, 07:56 AM) *
I don't think so. In DVB specification, for EIT present\following table, the table_id 0x4e(actual)or 0x4f(other), and the first section is for present event, the second one is for fellowing event. You could look 300468 file .


Are you absolutely sure about that? Can you give me a reference in the EN 300 468 document where it says this? I have just re-checked the document and I can't see this mentioned.

Whether or not you can infer anything from the section number, I still maintain that the best method is to simply compare start times. By definition, the start time of the following event has to be greater than that of the present event.
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dvbfreaky007
post Jul 15 2010, 09:12 PM
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QUOTE (pclare @ Jul 14 2010, 06:00 AM) *
Are you absolutely sure about that? Can you give me a reference in the EN 300 468 document where it says this? I have just re-checked the document and I can't see this mentioned.

Whether or not you can infer anything from the section number, I still maintain that the best method is to simply compare start times. By definition, the start time of the following event has to be greater than that of the present event.


In DVB Standards it wont say Event Present or Following with Section Number.

But In ARIB Standards, It will say Present EIT info if Section number = 0 and Following EIT info if section number =1
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Naples79
post Jul 23 2010, 08:57 PM
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if (section_number != last_section_number)
--present_event
else
--following_event
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pclare
post Jul 24 2010, 03:57 AM
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QUOTE (Naples79 @ Jul 23 2010, 10:57 AM) *
if (section_number != last_section_number)
--present_event
else
--following_event


As I have pointed out, this is not guaranteed to work for DVB. The following will work in every case and is just as simple:

if (event1.start_time > event2.start_time)
//event1 is following, event 2 is present
else
//event2 is following, event 1 is present

Actually, I think in many cases the above will be more efficient because the section numbers can be discarded earlier (since the section mechanism is essentially a wrapper around the SI data that we're really interested in).
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Gobes
post Nov 3 2010, 11:19 AM
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The rules for presesnt/following events, as the ETSI say in ETSI TR 101 211 are :

The SI bit stream shall have two sections per service for an EIT Present/Following with the section_number 0x00 reserved for the description of the present event and section_number 0x01 for the following event.
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pclare
post Nov 4 2010, 04:10 AM
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QUOTE (Gobes @ Nov 3 2010, 02:19 AM) *
The rules for presesnt/following events, as the ETSI say in ETSI TR 101 211 are :

The SI bit stream shall have two sections per service for an EIT Present/Following with the section_number 0x00 reserved for the description of the present event and section_number 0x01 for the following event.


Thanks for the ETSI spec reference. I'd been looking (and not finding) in EN 300 468 which is usually the main source of reference for this sort of thing. That's the trouble with these DVB specifications: the information you need is spread around in more than one document (and more than one standards committee if you consider the ISO MPEG standards).

From a software implementation point of view, I think that I'd still stick with looking at timestamps to distinguish between now and next.
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Gobes
post Nov 4 2010, 09:15 AM
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QUOTE (pclare @ Nov 4 2010, 05:10 AM) *
Thanks for the ETSI spec reference. I'd been looking (and not finding) in EN 300 468 which is usually the main source of reference for this sort of thing. That's the trouble with these DVB specifications: the information you need is spread around in more than one document (and more than one standards committee if you consider the ISO MPEG standards).

From a software implementation point of view, I think that I'd still stick with looking at timestamps to distinguish between now and next.



When you work with ETSI spec, just take a look at "Scope" section of the main ETSI EN* ( ETSI EN 300 468 in our case). There you will find the rules and guideline of the implementation, named ETSI TR * ( ETSI TR 101 211 in our case ). That't it how the ETSI work.
To compare the timestamps lead to the same result, but it's more easy to compare the sections number.

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