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entrecour

Improved teletext subtitles handling

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entrecour

Many of the Thor Canal Digital channels carry teletext subtitles. The languages for these are not correctly identified - instead a teletext numerical code is displayed in the subtitle selection list e.g. Teletext 885, etc.

 

On a commercial hardware STB the language code is displayed and subtitles can be correctly preselected. This is not currently possible with DVBV and it would be very nice if this could be supported.

 

If you need a sample .ts or any more info let me know.

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Griga
If you need a sample .ts or any more info let me know.

A sample would be helpful. I guess the language information is provided by teletext descriptors in the PMT (Program Map Table), as shown in the screenshot below, not by the teletext stream.

 

DVBViewer doesn't use this information yet. Maybe we can find a way to assign it to the according pages...

Zwischenablage01.png

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entrecour

Hi Griga,

 

Thanks for offering to look at this. Here is a 29 second sample....

 

teletext subtitle sample

 

Teletext and DVB subtitles format options were enabled for this recording. There are 4 teletext subtitle streams (Swedish, Norwegian, Danish, Finnish) and a "censored" stream which covers the whole screen - I have no idea what that is used for.

 

Wishing you and all the DVBViewer team a Merry Christmas.

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Griga

Thanks for the sample. It's quite interesting: The broadcaster makes extensive use of the teletext descriptor in the PMT, signalling several teletext subtitle pages in different languages. I'll meditate on it :) However, taking this into account may require structural changes in DVBViewer that will need some time...

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entrecour

OK - point taken. Thanks.

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boborg

The censored stream is for covering up X-rated movies in Norway I believe.

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jakeh

Many of the Thor Canal Digital channels carry teletext subtitles.

 

On a commercial hardware STB the language code is displayed and subtitles can be correctly preselected. This is not currently possible with DVBV and it would be very nice if this could be supported.

 

Great suggestion entrecour!

 

Also many of the Sirius Viasat channels carry same teletext subtitles. Both Canal and Viasat channels also provided by cable providers.

 

I am used to this missing automatic functionality as "feature" but definitely should be working in DVBViewer like with STB. Actually I asked long time ago from a STB user do he get automatically subtitles with these channels and he said of course.

It is quite ackward to select manually subtitles with trial and error method.

 

This usablibity improvement would greatly serve Nordic language natively speaking users.

 

P.S. It would be fun to inform to this particular STB user that actually there where no automatic selection issue with the teletext subtitles in DVBViewer ;)

Edited by jakeh

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majstang

This usablibity improvement would greatly serve Nordic language natively speaking users.

I second that! This thingy also applies to a few ComHem cabel channels as well.

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boborg

Hoping for this feature too, will improve DVBViewer usabilty for sure.

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Griga

Finally made it... I think this looks better now. It's a DVBViewer GE screenshot (not yet released) and the code will most likely be adopted for DVBViewer Pro.

 

As you can see the language of the censored page is "(eng)", because no language is assigned to it in the PMT (see my screenshot above). So DVBViewer displays the language of the first teletext descriptor entry, which is the general initial page in most cases. Dunno if we rather should leave the language empty in such a case...

 

I second that! This thingy also applies to a few ComHem cabel channels as well.

@majstang: Please check with the TransEdit Analyzer if there is a teletext descriptor in the PMT that assigns languages to different subtitle pages, or provide a sample.

Zwischenablage01.png

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majstang

@majstang: Please check with the TransEdit Analyzer if there is a teletext descriptor in the PMT that assigns languages to different subtitle pages, or provide a sample.

Yes, there is a descriptor in the PMT, but my broadcaster does not make extensive use of the teletext descriptor, they only signalling swedish teletext subtitle page. The other teletext subs in the ts file (Czech, Portugues or Spanish, Norweigian, Danish and Dutch) does not show in TransEdit Analyzer. Here is the sample:

http://www.megaupload.com/?d=55FGIIDZ

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Griga
they only signalling swedish teletext subtitle page

That's bad, because it lets DVBViewer display "SWE" for all subtitle pages. Seems we better only display a language if it is really assigned to the subtitle page in the PMT, and leave the rest empty.

 

There are additional language codes embedded in the teletext stream (no ISO three-letter codes, but binary numbers). The debugger reveales the following assignments in your sample:

 

Page 350: Czech

Page 451: Spanish (looks like Portuguese)

Page 691: Swedish

Page 692: Swedish

Page 693: Swedish

Page 888: French (looks like Dutch)

 

However, these language codes are intended for character set selection, not for display. We can't use them, because they are not designed for distinguishing Spanish and Portuguese, Swedish and Norwegian, Dutch and French... e.g. the last code only indicates that the French character set shall be used for page 888. I have no idea how the correct language information can be obtained.

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majstang

Seems we better only display a language if it is really assigned to the subtitle page in the PMT, and leave the rest empty.

Dont know what threadstarter entrecour thinks of this, but for me it is a satisfying solution indeed. Much better than earlier when being forced to toggle through each teletext sub in order to find the right language (at least the first time).

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entrecour

That seems fair enough to me.

 

Griga, Will it be possible to preselect the default language for all channels, and override for individual channels as needed?

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jakeh

That seems fair enough to me.

 

Griga, Will it be possible to preselect the default language for all channels, and override for individual channels as needed?

 

Griga, could subtitle language be automatically selected according ISO three-letter code selected in subtitle language settings and showed like in your screenshot. This is exactly how Canal and Viasat channels work and STB can automatically select subtitle language.

 

Maybe pages without ISO three-letter code can be left without language description.

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wikings1

text worked perfekt before 4.5 version on swedish providers

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majstang

text worked perfekt before 4.5 version on swedish providers

Not entirely sure what you mean? Of course teletext subtitles worked perfect before and now as well. This thread is about the difficulties of identifying what language the teletext subtitle contains only by reading the teletext numerical code and finding a way to give meaning to the numerical code and get that solution to work with all broadcasters/providers.

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boborg

So now the language is shown in version 4.8 but for me there is no way to auto enable them (set to danish in my case) or what?

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Griga
Griga, could subtitle language be automatically selected according ISO three-letter code

Sorry, that's not within my scope. I'm only providing basic code for DVBViewer Pro. Dunno if the DVB subtitle language selection can be extended for teletext.

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