The Wonderful World of VBI

Posted on 2006/08/12 05:07:57 (August 2006).

[Friday 11th August]
I'm a TV nerd you know. By this I don't mean I watch a lot of television - in fact here in Japan I hardly watch any at all - but I am really fascinated by the technology that makes it all work.

I found out this week that Japan use VBI on analogue TV in much the same way we do back in Europe. So there are subtitles/captions, and also a system of pages with textual information (and charmingly nostalgic block graphics) called Mojinet, a lot like our Teletext. It's interesting (to me at least) to compare the two standards. Mojinet is arguably more sophisticated - Japanese text is of course a bit more of an undertaking than the Latin alphabet, and the block graphics are more advanced. However it seems it was not widely used, and many people in Japan appear completely oblivious that such a thing ever existed. Perhaps the very fact that the Japanese standard was significantly more expensive to implement was the limiting factor there - a Teletext decoder chip was a relatively cheap addition to a TV, and so most sets in England would have one by default. Mojinet and Japanese captions, however, seem to be generally supported with the addition of a set top box which presumably most people couldn't be bothered with.

I was reading recently that a survey of closed caption usage in the USA identified that, actually, the bulk of users were not in fact the hearing impaired, but were instead people for whom English was not their first language. I'd experienced a similar thing with Chie back in England - she always wanted to have the subtitles displayed on screen wherever possible as it is often easier to read English than to hear it.

Whilst the situation with Japanese may not be exactly the same - most people find it more difficult to read/write than to speak/listen - still the addition of captions could well help to make Japanese TV a lot more accessible to people like me living in Japan.

This gave me a great idea for a piece of software. First off it seemed no PCTV solutions displayed these captions at all - which seemed a terrible waste. Secondly though, as these captions on analogue TV are just plain unencrypted text, it opened the door for a number of features that could be of great assistance to someone learning Japanese. For example, converting the kanji (symbolic characters) into hiragana (phonetic characters), or even a step further to romaji (the phonetic syllabary which uses the Latin alphabet). In the extreme you could even look into automatic machine translation - obviouly the sort of quality these systems product at present is still not perfect, but it might be good enough to give you an idea of what is going on.

So anyway the upshot of all this is that I spent a while in Akihabara today - Tokyo's district famous for selling electrical goods - looking for a TV tuner card which would give me access to the data I'd need to build this software on top of it. Of course, this wasn't a technical question that shop assistants would be able to answer, so in the end I just had to take a guess.

The initial results were not all that encouraging - frustratingly TV tuners are not all that standard, and once I got it home it seems the device I bought would only really work with the manufacturer's own software. Still, maybe there is a workaround for this, and there's still a possibility this project could work out.

Hmmm, this is an area I know little about, but given the way of things these days I wouldn't be surprised if the actual "chip" in most TV cards is just a generic type? To be honest though I've only ever had Hauppauge stuff and it's always been a pig to get set up and running well! I do fancy one of those USB DTT jobbies though, just to play with :)

Posted by Nigel at 2006/08/13 08:38:02.

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