A Sky, cable and digital tv forum. Digital TV Banter

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Home » Digital TV Banter forum » Digital TV Newsgroups » uk.tech.digital-tv (Digital TV - General)
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

uk.tech.digital-tv (Digital TV - General) (uk.tech.digital-tv) Discussion of all matters technical in origin related to the reception of digital television transmissions, be they via satellite, terrestrial or cable. Advertising is forbidden, with no exceptions.

Inconsistent implementation of DVB T1 standard?



 
 
Thread Tools Display Modes
  #1  
Old August 19th 13, 06:33 PM posted to uk.tech.digital-tv
Bill Wright[_2_]
external usenet poster
 
Posts: 9,381
Default Inconsistent implementation of DVB T1 standard?

I've been building a head end that has three DVB muxes, each carrying
four services. I tested it on a variety of TV sets and set top boxes.
The more interesting results:

New Sony TV set:
Listed all services in 'found' order, put them in 800 to 811.

Old Humax DTT box:
Put the services I had labelled BBC1, BBC2, ITV1, C4 into LCN 1-4, put
the other services into 800 to 807.

New Logic small screen combi set for UK:
Tuned 12 but displayed only ten, in random order. ****e.

New Logic small screen combi set for Belgium:
Tuned all twelve, put them in LCN 1 to 12. Magic!

Comments?

Bill
  #2  
Old August 19th 13, 07:28 PM posted to uk.tech.digital-tv
Steve[_27_]
external usenet poster
 
Posts: 4
Default Inconsistent implementation of DVB T1 standard?

On 19/08/2013 19:33, Bill Wright wrote:
I've been building a head end that has three DVB muxes, each carrying
four services. I tested it on a variety of TV sets and set top boxes.
The more interesting results:

New Sony TV set:
Listed all services in 'found' order, put them in 800 to 811.

Old Humax DTT box:
Put the services I had labelled BBC1, BBC2, ITV1, C4 into LCN 1-4, put
the other services into 800 to 807.

New Logic small screen combi set for UK:
Tuned 12 but displayed only ten, in random order. ****e.

New Logic small screen combi set for Belgium:
Tuned all twelve, put them in LCN 1 to 12. Magic!

Comments?

Bill


This is down to the country setting or country of origin or intended
market of the TV set concerned.

E.g. if the TV set is intended for the UK market, it will match up
channel IDs to LCNs well and shove everything else in the 800's

E.g. if the TV set is "universal for all markets worldwide", then it
will list all the channels in the order it finds them.

I discovered this by accident when a friends new BF moved from Spain to
the UK and brought their DTT TV set... The TV set was clearly intended
for Spanish DTT and the owner of said TV set (who is british
incidentally) moaned that the channel list order was not as expected,
i.e. BBC1, then BBC2, ITV, Ch 4 etc.

That particular TV listed everything in the order it was found in during
the scan. I expect in Spain they didn't have this 800 channels option.

You can vary this behaviour as many TV's have a sub menu that allows you
to tell it which country it is in.

The best analogy I can offer for this behaviour is a freesat reciever vs
a "proper sat receiver attached to the same twin output LNB pointed to
28.2 East. The two channel lists will not be in the same order....

HTH

Regards

Stephen.
  #3  
Old August 19th 13, 09:47 PM posted to uk.tech.digital-tv
madge
external usenet poster
 
Posts: 303
Default Inconsistent implementation of DVB T1 standard?

On Mon, 19 Aug 2013 19:33:20 +0100, Bill Wright wrote:

New Logic small screen combi set for Belgium:
Tuned all twelve, put them in LCN 1 to 12. Magic!
Comments?


Move to Belgium?

--
My Kindle/Mobile links page | All Kindles | http://goo.gl/ySe0d
Use these for low bandwidth | All Mobiles | http://KindLink.tk/
A really crap coded website | All Devices |
https://sites.google.com/site/themadge/
  #4  
Old August 20th 13, 02:28 AM posted to uk.tech.digital-tv
Bill Wright[_2_]
external usenet poster
 
Posts: 9,381
Default Inconsistent implementation of DVB T1 standard?

Steve wrote:

This is down to the country setting or country of origin or intended
market of the TV set concerned.

More to it than that. TV sets and set top boxes behave differently even
when all are told that they are in the UK.

Bill
  #5  
Old August 20th 13, 08:28 AM posted to uk.tech.digital-tv
Brian Gaff
external usenet poster
 
Posts: 6,811
Default Inconsistent implementation of DVB T1 standard?

Not enough testing of the software by the vendors!

Brian

--
From the Sofa of Brian Gaff Reply address is active
"Bill Wright" wrote in message
...
I've been building a head end that has three DVB muxes, each carrying four
services. I tested it on a variety of TV sets and set top boxes. The more
interesting results:

New Sony TV set:
Listed all services in 'found' order, put them in 800 to 811.

Old Humax DTT box:
Put the services I had labelled BBC1, BBC2, ITV1, C4 into LCN 1-4, put the
other services into 800 to 807.

New Logic small screen combi set for UK:
Tuned 12 but displayed only ten, in random order. ****e.

New Logic small screen combi set for Belgium:
Tuned all twelve, put them in LCN 1 to 12. Magic!

Comments?

Bill



  #6  
Old August 20th 13, 08:36 AM posted to uk.tech.digital-tv
Paul D Smith[_2_]
external usenet poster
 
Posts: 720
Default Inconsistent implementation of DVB T1 standard?

"Bill Wright" wrote in message ...

I've been building a head end that has three DVB muxes, each carrying
four services. I tested it on a variety of TV sets and set top boxes.
The more interesting results:

New Sony TV set:
Listed all services in 'found' order, put them in 800 to 811.

Old Humax DTT box:
Put the services I had labelled BBC1, BBC2, ITV1, C4 into LCN 1-4, put
the other services into 800 to 807.

New Logic small screen combi set for UK:
Tuned 12 but displayed only ten, in random order. ****e.

New Logic small screen combi set for Belgium:
Tuned all twelve, put them in LCN 1 to 12. Magic!

Comments?

Bill
++++++++++++
For our education, how should the TV know where to put various channels?
Someone must presumably provide a "mapping" but how is your system providing
this mapping? I might suspect that you are seeing....

Sony - resets everything, doesn't have a mapping so into 800+ with them
Humax - Guess the (5) main channels and shoves the rest into 800+
Logic (UK) - Crap, shoves them into a list as it goes and never tries to
reorder to 1+ or 800+
Logic (Belgium) - Any chance you've used if before and it's got an old
mapping that it has used to sort things out?

Paul DS.

  #7  
Old August 20th 13, 09:30 AM posted to uk.tech.digital-tv
Paul Ratcliffe
external usenet poster
 
Posts: 2,458
Default Inconsistent implementation of DVB T1 standard?

On Mon, 19 Aug 2013 19:33:20 +0100, Bill Wright wrote:

I've been building a head end that has three DVB muxes, each carrying
four services. I tested it on a variety of TV sets and set top boxes.


How are you generating these and what sets the LCNs, service info. etc.?

A Humax HDR Fox T2 with customised firmware is useful for investigating
transmission settings as you can query the tuning database and see what
is going on.

We generate our own mux. at work, but I've never had need/time to find
out what/how.

(Bloody hell, an on-topic thread... whatever next?)
  #8  
Old August 20th 13, 10:40 AM posted to uk.tech.digital-tv
Bill Wright[_2_]
external usenet poster
 
Posts: 9,381
Default Inconsistent implementation of DVB T1 standard?

Paul D Smith wrote:


Sony - resets everything, doesn't have a mapping so into 800+ with them

Yes

Humax - Guess the (5) main channels

This surprised me. The only way it know what they were was the fact that
I had inserted the text 'BBC 1' (etc) into the programme ident of the
modulators. The actual signals were satellite receiver outputs on
(mostly) foreign channels.

and shoves the rest into 800+
Yes

Logic (UK) - Crap, shoves them into a list as it goes and never tries to
reorder to 1+ or 800+

But the point is it found 12 but would only display 10! (and that in
random order)

Logic (Belgium) - Any chance you've used if before and it's got an old
mapping that it has used to sort things out?

New set. Two actually. Factory default used, set to Belgium.

Also did a factory default with the Sony; this then acted the same as
the Logic.

Bill
  #9  
Old August 20th 13, 04:38 PM posted to uk.tech.digital-tv
Bill Wright[_2_]
external usenet poster
 
Posts: 9,381
Default Inconsistent implementation of DVB T1 standard?

Paul Ratcliffe wrote:
On Mon, 19 Aug 2013 19:33:20 +0100, Bill Wright wrote:

I've been building a head end that has three DVB muxes, each carrying
four services. I tested it on a variety of TV sets and set top boxes.


How are you generating these and what sets the LCNs, service info. etc.?

Taylor MPX1 AV4 DBV T AVT units.

Bill
  #10  
Old August 21st 13, 09:05 AM posted to uk.tech.digital-tv
Glyn Morgan
external usenet poster
 
Posts: 46
Default Inconsistent implementation of DVB T1 standard?

On 19/08/2013 19:33, Bill Wright wrote:
I've been building a head end that has three DVB muxes, each carrying
four services. I tested it on a variety of TV sets and set top boxes.
The more interesting results:

New Sony TV set:
Listed all services in 'found' order, put them in 800 to 811.

Old Humax DTT box:
Put the services I had labelled BBC1, BBC2, ITV1, C4 into LCN 1-4, put
the other services into 800 to 807.

New Logic small screen combi set for UK:
Tuned 12 but displayed only ten, in random order. ****e.

New Logic small screen combi set for Belgium:
Tuned all twelve, put them in LCN 1 to 12. Magic!

Comments?



I haven't done any transport stream analysis for over 5 years, I am getting
older & rusty, things may have changed, so this is possibly a long shot.

My interpretation of your observations suggests that the Taylor multiplex is
not fully UK DTT compliant. Specifically that it does not comply with the
DTG D-Book particularly on how LCNs need to be defined. Particularly that it
seems to work ok with the New Logic small screen combi set for Belgium but
not UK.

The Sony putting the services in the 800s seems to confirm this however the
old Humax sounds a bit weird but might have its roots in a satellite or
other country DTT implementation that perhaps gives it a knowledge of
different methods of LCN transmission.

UK DTT uses a subset of the the DVB specifications and also includes some
service information (SI) that is a carried in different way. This is all
defined in a document distributed by the DTG and commonly know as the
"D-Book". This includes the way the LCNs are defined. For the UK these
are defined as being carried in a private descriptor in the NIT. Other
counties will carry these differently and may well use the original method
defined in the DVB specs.

Unfortunately the D-Book is only available to DTG members and membership is
probably expensive for small companies.

I think it would take a competent person with access to the specifications
and a transport stream analyser to really diagnose your problem.

I have had a look at the Taylor web site and I could not find any indication
that the multiplex complies with the D-Book. So I think the first thing to
do is ask them if it should be working ok with modern UK DTT receivers.

As I am sure you know details about the D-Book can be found on the DTG web
site he

http://www.dtg.org.uk/industry/dbook.html

I hope this helps,

Glyn




 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT. The time now is 03:18 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.SEO by vBSEO 2.4.0
Copyright 2004-2017 Digital TV Banter.
The comments are property of their posters.