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Re: ACTION-158: Exhaustive list of Test Cases for the temporal dimension in the Media Fragment URI

From: Yves Lafon <ylafon@w3.org>
Date: Thu, 15 Apr 2010 08:36:16 -0400 (EDT)
To: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
cc: raphael.troncy@eurecom.fr, Media Fragment <public-media-fragment@w3.org>
Message-ID: <alpine.DEB.1.10.1004150829170.14945@wnl.j3.bet>
On Thu, 15 Apr 2010, Silvia Pfeiffer wrote:

> All, in particular Yves,
>
> I just came across an interesting problem in our spec.
>
> In section 4.3.1 we have an example:
> t=10,     # => results in the time interval [10,end)
>
> But our production rule states:
> npttimedef    = [ deftimeformat ":"] ( npttime  [ "," npttime ] ) / (
> "," npttime )
>
> Making this a invalid specification.
>
> I don't think we want this, since there is not really a difference
> between t=10 and t=10,

I remember that we discussed that, and there was a decision to forbid 
"t=10," explicitely, hence the modification in the grammar.

> Thus I suggest to adapt the production rule to:
> npttimedef    = [ deftimeformat ":"] ( npttime  [ "," npttime ] ) / (
> "," npttime ) / ( npttime ",")
>
> Cheers,
> Silvia.
>
>
> On Wed, Apr 7, 2010 at 12:02 PM, Silvia Pfeiffer
> <silviapfeiffer1@gmail.com> wrote:
>> 2010/4/7 RaphaŽl Troncy <raphael.troncy@cwi.nl>:
>>>
>>>> 10, 11 and 12 have to be diversified based on whether a lies before or
>>>> after the beginning of the media resource. In fact, we need to
>>>> introduce something like s=start time and e=end time everywhere. Thus
>>>> we need to adapt/introduce the following:
>>>>
>>>> no5: t=a,b with s<=a, a<b, b<=e †=> †play a to b
>>>> introduce no5a: t=a,b with a<s, a<b, s<b, b<=e => †play s to b
>>>> introduce no5b: t=a,b with a<s, a<b, b<s, b<=e => †empty fragment
>>>> (these include no6 now)
>>>>
>>>> no7: t=a,b with s<=a, a<b, a<e, b>e => †play a to e
>>>> no7a: t=a,b with a<s, a<b, a<e, b>e => †play s to e
>>>> no7b: t=a,b with a<b, a=>e, b>e => †empty fragment
>>>> (this last one includes no8 and no9)
>>>>
>>>> no10: t=a, with a>=s, a<e => †play a to e
>>>> no10a: t=a, with a<s, a<e => †play s to e
>>>>
>>>> no14: t=,a with a>s, a< †d => †play s to a
>>>> no14a: t=,a with a<=s, a<d => †empty fragment
>>>
>>> OK, so for all these test cases, you assume fairly that the start time of a
>>> media resource is not necessarily 0. Is this a frequent case? How many media
>>> files out there have this property?
>>
>> It doesn't matter how many exist, but that this case can occur. Thus
>> we have to cover it in the test case.
>>
>>
>>>> Yup, listed above as a/b numbers and additional conditions to the ones
>>>> in the existing list. Mostly related to missing out on defining the
>>>> "start" time of the resource.
>>>
>>> I would add all these ones if the group feels it is necessary, i.e. there
>>> _are_ videos that will fall in these cases.
>>
>>
>> Yes, there definitely will be. The first media fragment server that
>> provides media fragment queries will create such resources. As we
>> encourage people to implement such services, we should also provide
>> for the possibility that such files will exist. Even if only 0.1% of
>> all files that now exist have that property.
>>
>> Cheers,
>> Silvia.
>>
>

-- 
Baroula que barouleras, au tiťu toujou t'entourneras.

         ~~Yves
Received on Thursday, 15 April 2010 12:36:19 GMT

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