# 888 analogue subtitles and playback via Panasonic TVs



## dvdfever (Jun 2, 2002)

I was wondering if anyone knew of the technical reason why I have a particular problem.

If I watch a programme with 888 analogue subtitles straight from my Sky box on my Panasonic 37" plasma TV (and previously on my 32" WS CRT TV) they're fine.

However, if I watch a recording on my TiVo, or even if it's live but it's passing through the TiVo's encoders (so, almost live) then the subtitles playback only occasionally and there's no rhyme or reason to why they appear.

I know it's not the TiVo because I tried it on a Thomson 28" WS CRT TV and they playback fine on that.

Obviously there's some conflict with the Pansonics so I was wondering if there's a solution for this, please (other than - get a non-Panasonic TV, or use the Sky box's built-in subtitles since those get burned into the print that's being recorded and they're uglier than 888 subs anyway). Ta.


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## Automan (Oct 29, 2000)

If you had the 'a' variant of tivo software on your box it strips off the teletext data as it upset some tv set teletext chipsets.

The quality of the teletext data must be degraded a bit by tivo at the best of times and perhaps the older crt tv is more forgiving.

How are the subtitles when AUX is pressed on the Tivo remote?


Automan.


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## dvdfever (Jun 2, 2002)

Automan said:


> If you had the 'a' variant of tivo software on your box it strips off the teletext data as it upset some tv set teletext chipsets.


I do have 2.5.5a on my main TiVo but it hasn't stopped the subtitles, or made them any different from it was before on 2.5.5



> The quality of the teletext data must be degraded a bit by tivo at the best of times and perhaps the older crt tv is more forgiving.


The odd thing is that the Panny CRT (on 2.5.5 and 2.5.5a) was just as bad as 2.5.5a on the Panny plasma. The 2.5.5 TiVo is fine on the Toshiba CRT, for what little I had recorded on there with 888 subs, as its source these days is a Freeview box.

I haven't tried the 2.5.5a TiVo on the Toshiba but I wouldn't use it in there normally anyway and it'd take too long to pull the AV rack apart to do it.



> How are the subtitles when AUX is pressed on the Tivo remote


Perfect. Inbetween speaking, I get the "*** TXT ***" line at the bottom of the screen. In fact, it's there when normal subs are too but it's a small price to pay for having 888 subs.

I was reminded of this last night while watching Doctor Who as I meant to watch it live, but by the time I got home it had already started (thanks to the dumb 6pm start like last year, rather than around 7pm like the previous years) and it was dropping out regularly.


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## Automan (Oct 29, 2000)

If the are are perfect in AUX Tivo bypass mode it is Tivo that is doing the damage.

Automan.


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## Sneals2000 (Aug 25, 2002)

ISTR that Tivo only records the page 888 data and doesn't record any other pages, and this causes problems with some TVs that look for other pages before they are happy. 

The Tivo doesn't record the 888 data as 'video' AIUI - it decodes the entire teletext stream, strips out the 888 pages and records them as data, and then re-inserts them on replay. Thus the output of the Tivo is just a teletext stream with 888 pages, which some TVs that try and store the entire stream don't like at all.

However the Tivo gets kudos for doing anything at all with teletext!

(The Tivo also inserts Line 23 WSS data as well on replay)


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## dvdfever (Jun 2, 2002)

Sneals, that sounds like you've hit the nail on the head. So the Pannys are trying to look for, or do too much with, any teletext info it's getting from the TiVo whereas the Toshiba is only concerned with 888 subs, or is just less fussy overall.

I guess any future Panny TV that includes 888 subs as an option is going to have this issue. 

Thanks very much for clearing it up, though.


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## mikerr (Jun 2, 2005)

Sneals2000 said:


> The Tivo doesn't record the 888 data as 'video' AIUI - it decodes the entire teletext stream, strips out the 888 pages and records them as data


 that's interesting - so Aiui there'll be basically a plain text script of all recorded programmes in mfs somewhere?

Would be handy to search by keyword/phrase...


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## Sneals2000 (Aug 25, 2002)

mikerr said:


> that's interesting - so Aiui there'll be basically a plain text script of all recorded programmes in mfs somewhere?
> 
> Would be handy to search by keyword/phrase...


I guess so.

Those of us who used to use BBC Micros in MODE 7 will be familiar with the 40x25 + attribute codes used by teletext. (Each colour change or double-height command took a character space)

BBC subtitles are double height - and required a CHR$141 (decimal) to select double-height and the line of text duplicated to create the top and bottom half of the characters ISTR. I think CEEFAX 888 subtitles will use the same format - though there may be a 128 bit difference - so it may be decimal 13 that indicates double-height rather than 141.

A character is also used to indicate the start and end of a superimpose box (i.e. the subtitle) - the start of a subtitle box is decimal 11 (or 139) and the end of a subtitle box is decimal 10 (or 138).

Foreground/text colour change codes (for different speakers) will probably be 1/129 to 7/135.

If you look for a decimal 11/139 followed by a decimal 13/141 (or vice versa) then you may find subtitles? (With every line of dialogue duplicated for the top and bottom halves of the double height text)

Something like

(11) (13) You're barred! Get out of my pub! (10)
(11) (13) You're barred! Get out of my pub! (10)

Where (XX) is a decimal character. Not sure if the top bit is set or not so it could be (139) (141) DIALOGUE (138)?

(Actually - is this a bit too close to extraction to be discussed?)


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## mrtickle (Aug 26, 2001)

mikerr said:


> that's interesting - so Aiui there'll be basically a plain text script of all recorded programmes in mfs somewhere?
> 
> Would be handy to search by keyword/phrase...


I'd be astonished if it was as nice and easy as "plain text". I think it's more likely to be packets of subtitle data all mashed in with the audio and video packets.

In theory you could use it to make a DVD-video with proper DVD subtitles (NOT closed captions), but alas it's years too late to do that development now. I couldn't persuade - at the other place - the author of a particular Tool which is often wrongly pluralised, to handle/allow our 16:9 broadcasts and set the widescreen flags where appropriate. (I manually add a stage to the process and fix using DVDPatcher instead). Subtitles from teletext data would be much more work than that!


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## Sneals2000 (Aug 25, 2002)

Yep - I would expect it to be packetised - but the teletext standard is quite neat - each TV line of VBI data carries one display line of text (i.e. 25 characters) ISTR.

(ProjectX has a neat system - it will export WST Teletext in DVB packet form as srt file, and DVB Subtitles as bit images. I've used both to create DVDs or MKVs in the past)


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## mrtickle (Aug 26, 2001)

Interesting, thanks. I've a friend with a Toppy who has used ProjectX as part of his DVD making process, and wanted to include/create DVD subtitles for a deaf friend of ours. I didn't realise it was that sophisticated


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