Thanks for your confirmation and answer.
À (At) 15:34 +0100 22/01/98, Andreas Kraft écrivait (wrote) :
>first, I agree with Guido that a Link which triggers on an event but has no
>defined event data fires on every event of this type.
>
>On Tue, 20 Jan 1998, Emmanuel BEUQUE wrote:
>> BTW, if this is possible, I don't think any clarification needed but
>> perhaps a note could prevent any confusion when reading the standard. In
>> fact, when reading the standard, it seems not obvious to me whether the
>> EventData attribute is optional because some EventType cannot have an
>> EventData or the EventData is optional even for other EventTypes.
>
>I think the text in section 13.1.2, part 4 is ok. But we need a clarification
>in 5.6 ("Overview of the MHEG-5 Classes", Link) where this "feature" is not
>mentioned.
>What do you think?
I agree with you that the standard is clear enough in section 13.1.2, part
4. Nothing there could make one think that the eventData must be encoded
for eventTypes that generates one.
I like your idea of a clarification in 5.6 which generally describes the
behaviour of links. I think this part is too much uncompromising about the
3 parts of a LinkCondition. The following sentence
"a Link fires only if it is active and only if the right event is
generated by the right object and contains the right event parameter"
could perhaps be changed like this :
"a Link fires only if it is active and only if the right event is
generated by the right object. If the event data of the link is
encoded, the link also requires the right event parameter in order
to fire."
But I also think that some part of the famous chapter 53 are also a bit
confusing, especially the following ones :
In section 53.1, just above the table :
"That value is used in order to determine whether the associated Link
should fire"
could rather be :
"That value can be used in order to determine whether the associated Link
should fire"
And more importantly, the last sentences of 53.1 :
"Events which types have associated data must always be generated with that
data. E.g., when a TimerFired event is generated, it must be accompanied by
the TimerIdentifier."
Could perhaps be completed with this :
"It is then the responsability of the link to encode this data or not as an
additional condition to be fired."
Even if the section 53.3 is rather clear and explicit on this point...
BR,
Emmanuel
__________________________________________________________________
Emmanuel BEUQUE mailto:ebeuque@pratique.fr
MediaServ tel: +33 (0) 2 99 64 35 64
Multimedia consultant & developer fax: +33 (0) 2 99 64 36 65