Re: SetData & ContentRef

Emmanuel BEUQUE (ebeuque@pratique.fr)
Thu, 22 Jan 1998 15:29:06 +0100

À (At) 10:32 +0100 22/01/98, Guillaume AUDEON écrivait (wrote) :
>This looks simple but unfortunately cannot work. Because
>GetLastAnchorFired returns its result in an OctetStringVariable and
>SetData takes the new content reference from a ContentRefVariable. And I
>have not been able to find a workaround in MHEG-5.

Guillaume certainly pointed out an MHEG inconsistancy here. IMHO,
GetLastAnchorFired would have better used a ContentRef variable rather than
an OctetString one.

>In addition, I found a solution provided by the DAVIC specifications:
> the use of a ResidentProgram, named "CastToContentRef".
>Would not it be simplier to extend the SetVariable action to take into
>account OctetString <-> ContentRef conversions?
>Should not this be addressed by the MHEG-5 Maintainance Task Force?

It's true that this kind of problem could be easily solved if there were
more variable type conversions allowed. Currently, there is only Integer
<-> OctetString conversions in MHEG-5 through the SetVariable action. It
would be interesting to have more such as OctetString <-> ContentRef but
why not others like Integer -> Boolean or Integer <-> ObjectRef and so on
for any conversion that could be useful.
However, it seems very hard to introduce this kind of new features in the
now published MHEG-5 IS. Suggestions like that were usually diverted to an
application domain specification like a set of ResidentPrograms.
That's why I think the ResidentProgram solution could be sufficient here,
but, of course, I would be glad also if MHEG-5 could evolve a little bit in
this area.

BR,
Emmanuel

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