Re: [Private Use Area] Audio Description, Subtitle, Signing

From: William Overington (
Date: Thu Jul 17 2003 - 12:01:18 EDT

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    Michael Everson raises some interesting points.

    >If CENELEC wishes to standardize a set of icons, they will do so. If
    >they have a need to interchange data using those icons, they will (if
    >they are wise) come to us an ask to encode them. If they want to use
    >the Private Use Area before they do that, they will.

    Perhaps I may explain the situation? The European Commission asked Cenelec
    to conduct a project about establishing a process to implement interactive
    television in the European Community.

    A consultancy was asked to produce a report. Cenelec organized a forum for
    the report to be discussed and also arranged an open meeting which was held
    in Brussels on 12 March 2003. The report was made available in the forum
    before the meeting.

    I did not attend the meeting, though I did post some comments into the forum
    before the meeting. A list of the people due to attend the meeting was
    published in the forum prior to the meeting. Most, though not all, are
    representing organizations.

    After the meeting a later version of the report was produced. The report
    suggests various aspects of the necessary work be done by various existing
    committees and standards bodies.

    The forum remains in use. One participant recently put forward the idea of
    agreeing on logos for Audio Description, Subtitle, Signing and provides a
    link to the page which I mentioned earlier in this thread.

    I added the suggestion of adding the symbols into the built-in font of
    DVB-MHP televisions. I suggested the desirability of regular Unicode code
    point allocations. I mentioned the time scale and I mentioned the Private
    Use Area code points for the symbols, that is one code point for each of
    Audio Description, Subtitle, Signing, not one code point for each of the
    logos being considered. I suggested some specific code points. I like to
    think that I quite clearly stated my interest in choosing those suggested
    code points so as not to clash with my suggestions for other uses of Private
    Use Area code points.

    For the avoidance of doubt, my suggestions for using Private Use Area code
    points for eutocode graphics do not need to be accepted by a standards body
    as they are only meaningful for use in text files which customize those Java
    programs which recognize them as they do not need to access the built-in
    font of the television set and they are only used in programs where the
    eutocode graphics system is used. There are glyphs for authoring-time, but
    no glyphs are needed for run-time use as the codes activate graphics
    features at run-time.

    So the specific suggestion for code points for Audio Description, Subtitle,
    Signing is within the forum.

    Now, I am unsure at present as to how the various committees and standards
    bodies are to proceed, yet I have sought to place my ideas in the forum in
    the hope that they will reach the agendas of the meetings.

    I also, some time later, posted the code point suggestions here. I did this
    with the intention of making the suggested code points more widely known.

    >Please don't tell us all about it over and over again, as you have

    Well, I made one post at the start of this thread. After that I have just
    responded to comments which have been made.

    >If you want to talk to CENELEC, do so. Please stop trying to
    >peddle your PUA schemes for CENELEC to us.

    Well, I had not thought of it as peddling!

    >I maintain the ConScript Unicode Registry, which contains PUA
    >assignments. I do not promulgate those on this list. (Apart from that
    >fun testing of the Phaistos implementation some time ago.)

    Well, that is a matter for you. Actually, I rather enjoy reading your
    postings and would indeed be pleased if you did post them in this forum.
    However, I do understand your point, though as this mailing list has rules
    which encourage discussions amongst users of the Unicode Standard, I feel
    that you are being somewhat harsh in your criticism.

    Anyway, you only joined in to a thread about the Phaistos Disc script, you
    did not start it as I seem to remember. So you were responding to an
    enquiry and, indeed, I feel, being very helpful in adding Phaistos Disc
    script into the ConScript Unicode Registry. It will be fascinating to
    observe what happens if an archaeological dig somewhere, maybe nowhere near
    where the Phaistos Disc was discovered, produces a lot of items with
    Phaistos Disc script upon them. Then instead of Unicode being ready, there
    will then be a long wait for a regular Unicode implementation, when it could
    have been done years ago!

    The taboo of discussing PUA code points which some people have causes lots
    of unnecessary problems. For example, the Unicode Consortium is so
    taboo-avoiding about mentioning PUA assignments that when I had some time
    ago heard that Microsoft used part of the PUA in a special way in symbol
    fonts I had enormous difficulty in finding out where it was located! Also,
    I seem to remember a long time ago trying to find out where it was that I
    had seen Tengwar encoded in the Private Use Area and not being able to find
    the link in the Unicode webspace.

    >Roozbeh and I assigned two unencoded characters for Afghanistan to
    >the PUA, and we encourage implementors to use them until such time as
    >the characters are encoded.

    Yes. I thought that that was an effective thing to do. You solved a
    problem at the time. Now that at least one of them has been approved for
    encoding by the Unicode Technical Committee there is now a long period of
    waiting during which Private Use Area encoded data can be produced. This
    does seem unfortunate and for individual symbols such as these I would hope
    that the people who are in charge of Standards might like to consider asking
    if the United Nations and the World Trade Organization could perhaps arrange
    for some faster way of achieving agreement. It does seem so very slow for
    the twenty-first century with so many electronics communications facilities!
    Why does legacy data have to build up and resolving the problem take so long
    for just a few symbols? I would have thought that with a reasonable
    infrastructure that those two code points could have been formally added
    into regular Unicode and ISO within a couple of weeks. The long process may
    well be necessary for whole new scripts and so on, yet for two characters to
    complete a high-profile project it seems to me to need justification of
    reasonableness in the present century.

    >We do not spend oceans of digital ink evangelizing our brilliant
    >schemes to the Unicode list.

    An ocean of digital ink! I like that phrase. And yes, it was brilliant of
    you both to go out there and do such a thorough job. It was good that you
    made the documents available on the web so quickly. I enjoyed looking at

    >>It is essentially a matter for end users of the system, just as the
    >>two Private Use Area characters being suggested in another thread of
    >>this forum in relation to Afghanistan are a matter for end users of
    >>the Unicode Standard and does not affect the content of the Unicode
    >>Standard itself.
    >Then go talk about it with the users of the system.

    Indeed. Yet I do feel that much is learned by reading posts in this mailing
    list on the various topics which arise and that it is on balance better to
    have the opportunity to have the information about the various uses of
    Unicode, including the Private Use Area, which are taking place than to be
    totally unaware of such things.

    The thing is, although you and a few others are critical of me for posting
    those three suggested Private Use Area code points into this mailing list,
    there may be people who were interested to read of them. Certainly no one
    has said so, so maybe nobody was interested. Yet people may not have even
    thought of writing to say that they found the post of interest, that is not
    how mailing lists work usually. Now that you and a few others are being
    critical, people may not wish to make a public statement even if they did
    find the post of interest.

    >>Code points for the symbols are needed now or in the near future.
    >Are they? By whom? And if they need to use the PUA, they can do so.

    Well, it was me who put forward the idea for code points so that the symbols
    could be included in the built-in font of an interactive television and
    signalled in Unicode text files in broadcasts. No one has actually stated
    public support for that idea. So, I suppose it might be that it is only me
    that thinks it would be a good idea. However, wherever ideas are put
    forward, often people do not comment if they agree and only comment if they
    disagree. Yet I will not disguise the fact that as yet no one has commented
    to me that code points for these symbols would be a good idea.

    It may perhaps be the case that no one is at all interested in code points
    for these symbols at this time.

    An interesting email arrived from one person on this list which commented on
    my posted comment in this thread.

    That person referred to this comment.

    > Well, I am here suggesting Private Use Area code points for interchange,
    > both in interactive broadcasting and in typesetting of magazines.

    That person politely asked me not to do that. That person added that people
    have been telling me for a long time that PUA codes are not suitable for

    That puzzles me, because I thought that it was alright to interchange
    Private Use Area codes if there is an agreement as to their meaning in a
    particular situation. Also, Unicode 3.0 mentions the possibility of
    publication of Private Use Area assignments in the section on the Private
    Use Area.

    So what is the official position please? This is important to me because I
    have been proceeding in the belief that suggesting three Private Use Area
    code points for use in interactive television systems is entirely proper and
    compliant with Unicode and the ISO standard.

    Returning to Michael's comments.

    >It's Private.

    Well, Unicode 3.0 specifically mentions the possibility of publishing
    Private Use Area code point assignments. There was talk of the section
    about the Private Use Area being rewritten for Unicode 4.0. Is there any
    chance of someone posting the Unicode 4.0 text into this discussion please?

    >>It remains to be seen what will be decided as the built-in font for the
    >>European Union implementation of the DVB-MHP specification. It might be
    >>the minimum font of the DVB-MHP specification or it might be more

    >>For example, should Greek characters be included? Should weather symbols
    >>be included? These and many other issues remain to be decided.
    >The minimum font for any specification for Europe should be the
    >MES-2. If you are talking to these people, tell them.

    Now, I have never heard of the MES-2 whatever that is. However, I do not
    have deep knowledge of the various standards which exist. Could you
    possibly say some more about MES-2 please.

    The minimum character set for DVB-MHP is in Annex E of the DVB-MHP
    specification, available from the webspace. It is all in
    one huge pdf file. I am hoping that the European Union will specify a
    rather more comprehensive font. It may be that a lot will depend on how
    much unused space, if any, there is in the read-only memories which are used
    for the built-in font.

    The Cenelec group to which I refer is the DigitalTV_WG and readers who might
    like to join could ask at as new members have joined at
    various times. Names of members are listed in the internal email facility
    of the forum. Membership is free and there appear to be people from outside
    the European Union as well as within it, as what is decided for Europe may
    be adopted by countries in other parts of the world.

    Readers might also be interested in the related TVforALL_WG forum which
    discusses issues of access to broadcasts for people with disabilities. The
    Audio Description, Subtitle, Signing logos issue has been posted in both of
    these forums. Please enquire at by email if you are
    interested. Membership is also free for that forum.

    William Overington

    17 July 2003

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