ATSC OTA EPG Updates

[mvallevand]

In trying to duplicate the EPG problem on a VM I use an HDHR with no guide. I modified my guide to get the EPG data and while the problem didn't arise the EPG was wrong. I have attached the npvr.db3 a log and an xmltv file that TSReader created for the same period. The times are off for sure but NextPVR didn't get all the shows either.

Note the scan time in NextPVR is one minute, in TS Reader it is almost instantaneous. Is that extreme time required?

Martin

[whurlston]

Note the scan time in NextPVR is one minute, in TS Reader it is almost instantaneous. Is that extreme time required?

According to the ATSC specifications, EIT is delivered in 3 hour blocks with a minimum of 4 blocks (12 hrs) and a recommendation of 12 blocks (24 hrs) but most broadcasters only use the minimum 4 blocks. Those blocks are labeled using a zero based index of the total number of blocks (EIT-0 to EIT-3). The recommended frequency for those tables to be sent are:

EIT-0: Once every 0.5 seconds
EIT-1: Once every three seconds
EIT-2 and EIT-3 (and higher): Once every minute

So if you want at least a 12 hour EPG, then NextPVR needs to wait at least a minute to ensure that you are getting all 4 EIT blocks.

For channel information (TVCT/CVCT data), you need two minutes to ensure that you have all the data.

[mvallevand]

According to the ATSC specifications, EIT is delivered in 3 hour blocks with a minimum of 4 blocks (12 hrs) and a recommendation of 12 blocks (24 hrs) but most broadcasters only use the minimum 4 blocks. Those blocks are labeled using a zero based index of the total number of blocks (EIT-0 to EIT-3). The recommended frequency for those tables to be sent are:

EIT-0: Once every 0.5 seconds
EIT-1: Once every three seconds
EIT-2 and EIT-3 (and higher): Once every minute

So if you want at least a 12 hour EPG, then NextPVR needs to wait at least a minute to ensure that you are getting all 4 EIT blocks.

For channel information (TVCT/CVCT data), you need two minutes to ensure that you have all the data.

Thanks whurlston, that explains the length of time, now the problem is just NextPVR importing the data properly.

Martin

[whurlston]

sub will have to answer that part (but you knew that already).

[sub]

It's been a really long time since I looked at ATSC EPG, but if you can make a 1 minute recording available, I'm happy to take a look.

The main reason we wait up to a minute, is because DVB systems are required to have transmitted all their EIT information with a minute.

[mvallevand]

It's been a really long time since I looked at ATSC EPG, but if you can make a 1 minute recording available, I'm happy to take a look.

The main reason we wait up to a minute, is because DVB systems are required to have transmitted all their EIT information with a minute.

Here's a link to the full ts file.

http://www2.zippyshare.com/v/46702619/file.html

[sub]

Here's a link to the full ts file.

http://www2.zippyshare.com/v/46702619/file.html

Thanks.

I've not come across zippyshare before, but I'm not sure I agree with their name...the time remaining is jumping up and down between 5 hours and 7 hours. Neither of these would be "zippy" in my book.

[mvallevand]

Thanks.

I've not come across zippyshare before, but I'm not sure I agree with their name...the time remaining is jumping up and down between 5 hours and 7 hours. Neither of these would be "zippy" in my book.

Sorry about that, it took under 30 minutes to upload so I figured d/l would be even faster. I'll look for alternatives next time.

Martin

[sub]

zippy must have eventually speed up, and the download completed. Annoyingly TSReader isn't opening the file (I'm guessing the download might have stopped prematurely, so there may be garbage at the end of the file).

I've confirmed I get listings, but it's proving challenging to determine what times I should see for the listings, since I'm in a different timezone. How far out are looking for you?

[sub]

In my TV Guide, it shows "Battle of the blades" currently airing, and "little mosque on the prairie" about to start in 15 minutes, followed by "Mr D" 30 minutes after that. Looking at http://tvlistings.zap2it.com/tvlistings/...hannel=4.1, that seems to match reality in that of the world.

(ie, UTC should be the same regardless of where I am in the world, so it should show the same currently airing show)