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Extracting/Using LCN Data


IanSav

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Hi,

 

I have noted a few posts from people who want to renumber channels in DVBViewer. I haven't found any serious discussion on the issue or any developer input on the topic.

 

I would like to encourage the developers to please reconsider the use of channel numbers as more than a simple numeric index into a channel database. By all means keep the current simple numeric index into the channel database as a unique primary field index key but please consider adding a new field that contains the broadcaster or user assigned Logical Channel Number (LCN) that can be used throughout the UI and for direct channel selection via the keyboard or remote control.

 

In Australia, as well as many other places, the broadcasters transmit a commonly referenced LCN for each of the channels. This LCN is well known and often referenced in TV guides and the mass media. Unfortunately this LCN is not available in TransEdit or DVBViewer. This makes diagnostics and directly selecting a channel by its well known LCN impossible. Further, in Australia, some of our broadcasters have taken to transmitting multiple channels with subtle differences like the LCN but with the SAME name. The only easy way to tell these channels apart is with the broadcast LCN. However in TransEdit and DVBViewer the LCN is not available so these duplicates are difficult, if not impossible, to tell apart.

 

Once we get support for a LCN field then it would be an easy extension to grant the wish to have user assigned numbers to be used as the LCN. That is any user can renumber any LCN to suit their environment. Because the LCN is not the primary index of the channel data, just an attribute, then there should be no issue in managing the channel database more or less like it is done currently.

 

If any of the developers would like any information or samples of Australian broadcast TV I would be pleased to try and assist.

 

How do people feel about this proposal? Can we please have some discussion, input or comment from the developers?

 

Regards,

Ian.

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I agree with you, but you're a little wrong as Griga has already added LCN "decoding" to TransEdit's Analyzer; you can find the LCN root entry of a transponder searching for "x83" in the left of the Analyzer window; it work perfectly for italian DVB-T, please report here if it is working also for you...

 

Unfortunately LCN data is still unused in TE or DVBV, maybe as (AFAIK) to take advantage of that data, a deep/complete rework of entire channel list structure/managment is required... so good to ask for but better don't hold own breath to see this implemented :rolleyes:

 

:bye:

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The Logical Channel Descriptor is not part of the DVB specifications. It is a "private" EICTA extension. In many countries / DVB networks it is not used at all. Thus a general LCN based channel list handling is not possible. Implementing it in addition to the "normal" handling would require quite a lot of IF...THENs, and that's something developers don't like to do...

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Hi Gioxy,

I agree with you, but you're a little wrong as Griga has already added LCN "decoding" to TransEdit's Analyzer; you can find the LCN root entry of a transponder searching for "x83" in the left of the Analyzer window; it work perfectly for italian DVB-T, please report here if it is working also for you...

Yes, the data is buried within the Analyser function. I was hoping that this information could be extracted and displayed in a column of the TransEdit Scanner results window. For example if LCNs are available then the first column of the Scanner results list could be "LCN" followed by "Name", "Provider", etc.

 

By the way, if LCN data isn't broadcast in an area that doesn't mean that the user doesn't want to assign their own numbering scheme to the available channels. Also, even if the LCNs are broadcast the editing capability could be used for those users who want to reorganise the LCNs in their system.

Unfortunately LCN data is still unused in TE or DVBV, maybe as (AFAIK) to take advantage of that data, a deep/complete rework of entire channel list structure/managment is required... so good to ask for but better don't hold own breath to see this implemented

If it is added as another attribute and not a primary key then I would hope that it wouldn't be too hard to do. Anyway the wish is out there hopefully the developers will find a way to grant the wish.

 

Regards,

Ian.

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Hi Griga,

The Logical Channel Descriptor is not part of the DVB specifications. It is a "private" EICTA extension. In many countries / DVB networks it is not used at all. Thus a general LCN based channel list handling is not possible. Implementing it in addition to the "normal" handling would require quite a lot of IF...THENs, and that's something developers don't like to do...

As I suggested to Gioxy, this new LCN data field can be added as an additional field that complements the currently used channel number that is automatically assigned by DVBViewer as each channel is scanned. If the LCN data is broadcast then initialise the LCN field with the broadcast data. If the data is not available then leave the field blank or default the LCN to 0. This value can always be edited by the user later.

 

I accept that it would be a significant and difficult task to rework the entire channel management system to cope with non sequential and possibly non present LCN data during a channel scan. I propose that there is no need to replace this unique and sequential index number in the database just add the LCN as a new field.

 

Regards,

Ian.

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I was hoping that this information could be extracted and displayed in a column of the TransEdit Scanner results window...
By the way, if LCN data isn't broadcast in an area that doesn't mean that the user doesn't want to assign their own numbering scheme to the available channels.

IanSav proposals suggest me a possible "half" solution (hoping Griga will consider/agree with it): add the LCN value only in Transedit results window to (eventually) reorder channels accordingly, so that the exported channel list is already LCN ordered...

 

Later, to complete the first half solution, another idea could be to rework only the DVBViewer favourites managment (so leaving the "delicate" real channellist untouched...) to accept empty jumps in the channel numbering, and fill those favourites with a special (channel)favoutite list created with a "LCN enabled" Transedit...

 

:bye:

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Hi Gioxy,

 

While I agree that this LCN data can be used for default channel sorting this is not the reason I have asked for LCN information to be added. For me the important aspects of adding LCNs are:

  1. To be able to tell the difference between the different channels called "ONE" on LCNs 1 and 12, "ABC 1" on LCNs 2 and 21 and "7 Digital" on LCNs 7,and 70.
  2. To be able to use the keyboard or a remote control to directly select a channel by using the well known LCN rather than a an effectively number assigned during the channel scan.

I accept that many people will want to sort the channel list based on the LCN. In my case I *don't* want to sort the channels by LCN. I cluster the channels by broadcasters and this list the SD channels first, then the HD channel.

 

Regards,

Ian.

Edited by IanSav
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To be able to use the keyboard or a remote control to directly select a channel by using the well known LCN rather than a an effectively number assigned during the channel scan.

That's exacly what bring the "second half" of my solution, probably the most important: rework the "Favourites" list to accept "custom" channel numbers; IMO that's all what we need to do what we want.

Long (informatical) time ago another italian user made a little app that modify the "favourites.xml" file adding "dummy" empty channels to move (and so renumber) channels in the desired positions, also with "jumps" of hundreds between channels, and that do the job very well from the keyboard and the remote, but - as you can imagine - the tricked Favourite list was almost unwatchable...

 

:bye:

Edited by Gioxy
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Hi,

 

I hope people understood point number 2 in my previous post even though the word "random" went missing. What I meant to post was:

To be able to use the keyboard or a remote control to directly select a channel by using the well known LCN rather than a an effectively *random* number assigned during the channel scan.

That is, every time the available channels are scanned it is possible, and has happened here a few times, that the available list of channels changes causing the scan order to change. With the scan order changed so to do the assigned channel numbers.

 

Sorry for any confusion the mistake in my post may have caused.

 

Regards,

Ian.

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Hi Griga,

 

If you update TransEdit in response to my bug report post regarding the German shortcut names in the English version of TransEdit would you please consider adding the LCN information in the Scanner list results of the channel scans. At this stage I am not asking for a complete rewrite to support LCN based decisions etc but simply a column in the Scanner results window that lists the LCN data if it is defined/used in the broadcast data stream. If the data is not present than leave the column blank.

 

Regards,

Ian.

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but simply a column in the Scanner results window that lists the LCN data

It isn't simple.

 

The LCN Descriptor ist part of the NIT. Usually the scanner doesn't examine the NIT, only optionally parts of it for a special purpose (transponder list update). Reading the NIT slows down scanning considerably (the repetitiveness is quite low) and may cause unwanted side effects if a transponder list update is not desired / not appropriate. Furthermore descriptor parsing must be added, plus a search for the Service ID referencing the channel in the internal service list representing the PAT content.

 

So what you want would require several structural changes in the UI and code - much more than "simply adding a column".

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Hi Griga,

 

Thank you for responding.

 

I was having a look around the TS Analyser in TransEdit and it appears that the Logical Channel Numbers *are* part of the NIT structure here. Please excuse me if I am not looking at the data correctly. Would some XML dumps from the TS Analyser of the various channels available in Melbourne Australia help?

 

Regards,

Ian.

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  • 2 years later...

To be able to use the keyboard or a remote control to directly select a channel by using the well known LCN rather than a an effectively number assigned during the channel scan.

I accept that many people will want to sort the channel list based on the LCN.

I would like to do both these things.

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