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Re: Aligning NPT syntax with RTSP

From: Philip Jägenstedt <philipj@opera.com>
Date: Fri, 29 Jan 2010 00:05:37 +0100
To: "Silvia Pfeiffer" <silviapfeiffer1@gmail.com>
Cc: public-media-fragment@w3.org
Message-ID: <op.u69mfnmksr6mfa@worf>
On Wed, 27 Jan 2010 23:28:05 +0100, Silvia Pfeiffer  
<silviapfeiffer1@gmail.com> wrote:

> On Wed, Jan 27, 2010 at 11:45 PM, Philip Jägenstedt <philipj@opera.com>  
> wrote:
>> On Wed, 27 Jan 2010 13:32:11 +0100, Silvia Pfeiffer
>> <silviapfeiffer1@gmail.com> wrote:
>>
>>> On Wed, Jan 27, 2010 at 10:33 PM, Philip Jägenstedt <philipj@opera.com>
>>> wrote:
>>>>
>>>> On Wed, 27 Jan 2010 12:23:25 +0100, Silvia Pfeiffer
>>>> <silviapfeiffer1@gmail.com> wrote:
>>>>
>>>>> On Wed, Jan 27, 2010 at 10:09 PM, Philip Jägenstedt  
>>>>> <philipj@opera.com>
>>>>> wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>> http://www.w3.org/2008/WebVideo/Fragments/WD-media-fragments-spec/#npttime
>>>>>>
>>>>>> This is what I mentioned in the teleconf. As it is, '0.' would not  
>>>>>> be a
>>>>>> valid production of npttime but it is a valid production of npt-sec
>>>>>> from
>>>>>> RTSP [1]. The same is true of '00:00:00.'. The difference is in  
>>>>>> digits
>>>>>> after
>>>>>> the decimal point.
>>>>>
>>>>> We currently have:
>>>>>
>>>>> npttime    ::=          ( 1*DIGIT [ "." 1*DIGIT ] [ timeunit ] ) |
>>>>>                       ( 1*DIGIT ":" 2DIGIT ":" 2DIGIT [ "." 1*DIGIT]  
>>>>> )
>>>>>
>>>>> which I think you are proposing to change to
>>>>>
>>>>> npttime    ::=          ( 1*DIGIT [ "." *DIGIT ] [ timeunit ] ) |
>>>>>                       ( 1*DIGIT ":" 2DIGIT ":" 2DIGIT [ "." *DIGIT] )
>>>>>
>>>>> Correct?
>>>>
>>>> To be precise, I'm suggesting referring to the definition in RFC2326,  
>>>> noy
>>>> copying it. The effect is the same of course.
>>>
>>> Could do ...  otoh if the RTP spec changes this, we are not
>>> dependent... and it's really short.
>>
>> RFCs can never change, but I have no objections to copying as long as  
>> there
>> is a (normative?) reference to RFC2326 for readers to follow.
>
> Yeah, that's right. I guess the only reason then is not to have to go
> and read another document.
> I'm happy to add a normative reference to RFC2326 and still leaven the
> two-liner in there.

I tried making the edit and it turns out RFC2326 is a bit quirky on the  
HHMMSS format:

    npt-hhmmss   =   npt-hh ":" npt-mm ":" npt-ss [ "." *DIGIT ]
    npt-hh       =   1*DIGIT     ; any positive number
    npt-mm       =   1*2DIGIT    ; 0-59
    npt-ss       =   1*2DIGIT    ; 0-59

It allows 1-digit minute or second, which we currently do not. Do we  
really want this?

-- 
Philip Jägenstedt
Core Developer
Opera Software
Received on Thursday, 28 January 2010 23:06:31 GMT

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