G'day Daniel, I just came up with a couple more ideas that could be worth mentioning, that you can keep in mind for the future... On Fri, 23 Jan 2009, BOUWSMA Barry wrote: > The other output format is `pids', and here's that from > back in 2006, before the use of the second audio channel > on the german broadcasters became widespread (last year): > > ZDF (0x6d66) 01: PCR == V V 0x006e A 0x0078 \ > (deu) 0x0079 (2ch) TT 0x0082 AC3 0x007d > > Here PID 0x79 is tagged as `2ch' (it's NAR for the Beeb), > and covers both audiodescription and occasional original- > language (mostly english language) broadcasts without > overdubbing. This was before DVB subtitles were introduced. > > Oh, here's an old BBC `pids' output, also including subtitles: > > BBC 1 London (0x189d) 01: PCR == V V 0x1388 A 0x1389 \ > (eng) 0x138a (NAR) TT 0x138b SUB 0x138c Now, I want to mention in detail the TT (teletext) and SUB (subtitle) services, at least, how they are implemented in this part of europe -- other parts of the world will likely be different, but my purpose is to throw around ideas in the hope that something will stick to the ceiling and be interesting and possibly useful. I mentioned that I find the nearly 100% penetration of subtitles to be quite useful to me personally, although it and in-field signing are intended for people whose hearing is not so good as mine, but whose vision is intact. The subtitles are sent in both a selected teletext page, as well as a separate DVB-subtitle stream. Unfortunately, the support that `mplayer' has for DVB subtitles last I knew, is, well, bad to none, and basically requires completely rewriting that bit. `xine' worked better some months ago, but at that time had some timing problems. Anyway, as I understand it, DVB subtitles are sent as bitmaps, which unfortunately makes it difficult for you to use them. This also explains the difference in appearance between the BBC subtitles and those of ITV. However, I haven't seen mangled fonts due to transmission errors, while I have seen incorrect yet properly-formed characters at times. So my understanding of DVB subtitles is far from complete or correct. Standard teletext, as was introduced with analogue transmissions as part of the vertical blanking interval, has been carried over to DVB broadcasts. In the case of the BBC, this is mostly limited to subtitles on page 888, while the german services I've mentioned offer full text services, occasionally including subtitles, but on a limited set of programmes. Only the ZDF has both teletext and DVB subtitles at present, of the german public broadcasters. These DVB subtitle fonts again differ in appearance from any of the british public broadcasters. In the UK, the move has been away from conventional teletext with the introduction of digital services, replacing it with an MHEG-based service. In germany, there has been a push to supplement regular teletext with an MHP-based service, but for lack of interest and readily-available hardware, this has pretty much died out or stagnated. I seem to recall that in Australia, use is made of an MHEG service. I don't know if a regular teletext service is available -- you will see this in the results, when you have a tuner capable of scanning. Now, ideally, a teletext service, being text-based, can be trivially converted to braille or spoken. I'm not sure about the MHEG services, as they seem to place more importance on the on-screen appearance, yet they do use a TrueType font. Anyway, while conventional teletext is not simple ASCII-like, it is based on a hamming of a limited character set which can be converted back to a standard 128- or 256-character set font, and of course the normal characters can be displayed as braille. Now, here is an example of some of the useful information to be found on a full teletext service, to show that, if it were available to you, you might find it interesting. This is a page giving inter-bank exchange rates from the Euro to your own currency, and is meant as an example (it's in german, but should be trivial to understand) /GIP IG*** PHOENIX Mi 21.01.09 18:01:45 PHOENIX.text 2/2 Devisenkurse Letzte Datenabfrage Diff. Kurs- 21.01.09, 18:00 Uhr Vortag zeit USA....... (USD) 1,2857 -0,20% 17:59 GB........ (GBP) 0,9369 +0,94% 17:59 Schweiz... (CHF) 1,4767 -0,13% 17:59 Japan..... (JPY) 112,9800 -2,35% 17:59 Kanada.... (CAD) 1,6365 +0,37% 17:59 Südafrika. (ZAR) 13,0970 -1,05% 17:50 Hongkong.. (HKD) 9,9990 +0,07% 17:49 Singapur.. (SGD) 1,9401 -0,13% 17:50 Australien (AUD) 1,9804 -0,23% 17:59 Neuseeland (NZD) 2,4637 -0,78% 17:49 Indien.... (INR) 63,3633 +0,36% 17:49 China..... (CNY) 8,8013 +0,03% 17:15 Mexiko.... (MXN) 17,9189 -0,85% 17:49 Argentin.. (ARS) 4,4618 +0,33% 17:16 Brasilien. (BRL) 3,0380 -0,73% 17:54 Sortenkurse -> (reproduced without permission, sorry) Unfortunately, relatively few programmes are sent with any subtitles, and I'm having to dig deeply in my snapshots of teletext pages to find an example I can show, instead of // X G*** PHOENIX Mi 21.01.09 18:01:38 KEINE UNTERTITEL (no subtitles) More unfortunately, I've just verified that my utility is not recognizing and writing to disk the subtitles that are currently being broadcast on page 150 by one particular broadcaster, so it's back to the coding for me... Meaning, I can't paste an example here. However, my point is that if this type of service is broadcast in your area, you may find it interesting and useful, as you would be able to make use of the text content within. Just an idea which I had... By the way, I don't know how foreign non-english-language films would be handled by your broadcasters. In general, the text- based subtitles are not sent when there are on-screen subtitles, for example, when the BBC screens a film in its native language and subtitles. That means that, for example, the film ``Lola Rennt'' was sent out with the primary audio channel containing the original german, and no teletext subtitles, with the translation into english appearing as part of the video signal, meaning that you can't make use of it, nor could you make use of the audio (if you understand german, then substitute french, portuguese, japanese, or some other language which has been broadcast as original-with-subtitles). Other broadcasters tend to dub everything of serious commercial value into the native language with the same limited number of voice talent, so the issue of original audio versus subtitles doesn't come up. The cultural channel `arte' is somewhat an exception, where via the different satellite positions you might find dubbed german, dubbed french, and original english, subtitles in french or german, or original language broadcasts in the `trash' series of cinematic gems with on-screen subtitles in either french or german, keeping out those audience members unable to understand the original and unable to see the on-screen subtitles... barry bouwsma -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html