Subtitle recording DVD

Discussion in 'Video Cameras' started by Neil, Oct 27, 2003.

  1. Neil

    Neil Guest


    Does anyone know if any of the currently available DVD recorders will
    record subtitles (teletext page 888), from standard analog terrestrial
    tranmissions, and play them back as and when required?

    Neil, Oct 27, 2003
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  2. Almost certainly not in their original form. AFAIK the lines they
    are on are outside the capture area of DV bridges/capture cards.

    (Mind you - I haven't tried it, but I've never seen VITS captured
    either, and these are in the same area in the frame.)

    If you let the subtitles appear in the video-stream then, of
    course, they will be captured.

    There used to be a problem that the sharp edges of the teletext
    pulses were severely damaged by older video tape recorders - and
    wouldn't appear on replay because of that. Don't know if this would
    be the case if you persuaded some capture device to capture outside
    the normal frame area.

    Harry Broomhall, Oct 27, 2003
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  3. Neil

    Jukka Aho Guest

    The DVD format only stores the "active" part of the video,
    i.e. the area on which there is picture in the signal.
    There are no provisions in the DVD format to digitize and
    store all of the analogue signal (including the blanked
    parts.) Blanking is recreated during playback, not stored
    on the disc.

    As teletext transmissions happen during vertical blanking,
    the only way to get them on DVD would be decoding the signal
    while digitizing and storing it in some other format on the

    As far as I know, the DVD format (unlike DVB transmissions)
    has no support for storing teletext data in any format.
    Technically, it is probably _possible_ to store the data in
    the MPEG-2 stream one way or the other (there are some
    standards for this, created for other MPEG-2 applications),
    but the DVD players - unlike DVB receivers - are not required
    (by the DVD specifications) to be able to encode any such
    data back to actual teletext signals (i.e. insert it in the
    vertical blanking during playback.)

    * * *

    The best way of solving the problem would be a system which
    automatically decoded the teletext subtitles (while recording)
    and converted that data to DVD subtitles on the fly. However,
    even if technically possible, it is somewhat unlikely that
    the current DVD recorders would have this kind of sophisticated
    Jukka Aho, Oct 28, 2003
  4. Neil

    Neil Guest

    Thanking you both.

    (a) I read in this week's Radio Times that most of the BBC's DVD's are
    now subtitled. Have you any idea how this might work if DVD does not
    support subtitles? (ref RT 25-31 Oct, page 8)

    (b) Would I be able to use DVD to capture and play back subtitles
    transmitted by digital TV signals (rather than analog)?

    (c) Could I get a suitable TV capture/playback card for my PC, and hence
    use the PC for subtitle recording/playback purposes (with a normal TV)?

    Neil, Oct 28, 2003
  5. DVD *does* support sub-titles. Just not the same way as done by
    Probably not. But 'Digital TV' is a whole other subject, which
    I'm not really qualified to talk about! (Mostly because it isn't
    available here!)

    Define what you are trying to do here. If the subtitles are
    rendered on top of the TV pic then it will record. Otherwise I think
    it unlikely.

    Basicaly - what you want to do (I believe) is to automaticaly
    record TV with teletext subtitles. The end result is to be a DVD with

    As Jukka said in his last paragraph, this is not easy, and I don't
    know an easy and simple way of doing this. Such a thing may exist,
    but I haven't seen it.

    Harry Broomhall, Oct 28, 2003
  6. Neil

    Jukka Aho Guest

    DVD has its own subtitling format which is not directly compatible
    with the teletext subtitling format. As I already hinted in my
    previous message (in the last paragraph), it is technically
    possible to receive and decode teletext subtitles and then
    convert them to DVB-style subtitles (if given suitable equipment
    and software), but at the same time it is quite unlikely that
    any of the stand-alone DVD recorders would do this automatically
    on behalf of the user.
    There is probably a greater chance of seeing this happening
    in the future, but I do not know if there are any stand-alone
    DVD recorders doing it automatically yet.

    Of course you can always record the subtitles on DVD if
    they have been "burned in" to the picture, instead of
    being superimposed on the fly by your telly. For example,
    if you have a VCR with Teletext capabilities, you
    could probbably have it output the subtitles in this
    "burned in" format to your DVD recorder.

    Also, a digital set-top box should be able to provide
    analogue signals with burned-in DVB subtitles - it is
    just that then you get an extraneous digital-to-analog
    and analog-to-digital conversion cycle.

    Unfortunately, resorting to burned-in subtitles means
    that there is no way to turn them off anymore; they
    have been permanently recorded on the picture as if
    they were part of it. If you record them this way,
    they will always be visible when you play back your

    The only way to get around this problem is decoding/
    storing subtitles separately while capturing the video
    and then converting them to the DVD subtitling format
    before burning a disc. It is quite likely (at least
    for the time being) that you need a PC and some
    exotic subtitling tools & utilities to get anything
    like that done.
    A PC with a teletext-capable TV card is at least _technically_
    able to receive and record teletext subtitling data. Once you
    have the subtitles stored in some reasonable format, it should
    be possible to convert them to DVD subtitles as well.

    However, the teletext-capable capture cards probably do not
    usually come with any other teletext software than just a
    basic teletext viewer, so you would probably need to check
    first if you can find some 3rd party teletext subtitles
    decoder/recorder utility from the net for the card you
    intend to purchase before actually buying it.
    Jukka Aho, Oct 28, 2003
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