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Re: Range syntax

From: Jack Jansen <Jack.Jansen@cwi.nl>
Date: Thu, 10 Sep 2009 16:05:10 +0200
Cc: Davy Van Deursen <davy.vandeursen@ugent.be>, public-media-fragment@w3.org
Message-Id: <0CBEBEA5-7910-49D9-AE33-1D1F657E8BF1@cwi.nl>
To: Yves Lafon <ylafon@w3.org>

On 9 sep 2009, at 14:36, Yves Lafon wrote:

> On Wed, 9 Sep 2009, Yves Lafon wrote:
>
>> All,
>> I has two ideas for solving this one.
>> The first one is very straighforward and reuse the units we already  
>> defined:
>> Range: npt=12:23.2s-13
>> Range: smpte-30-drop=1:22:33-2:33:44
>>
>> ie: Range: <timeformat> '=' <start time> - <end time>
>>
>> And the same logic for Content-Range:
>>
>> Content-Range: npt 12:22.5-13.01/25.1
>> Content-Range: smpte-30-drop 1:22:33-2:33:44.1/4:00:00
>>
>> ie: Content-Range: <timeformat> ' ' <real start time> '-' <real end  
>> time>
>>                  '/' <total duration>
>>
>> Note that the use of '=' and ' ' is aligned with the Byte range  
>> definition.
>>
>> The other option would be to say that it's a time unit, and precise  
>> the unit later:
>>
>> Range: time=npt:12:22.7-npt:13
>> =>
>> Content-Range: time=npt:12:22.5-npt:13.01/npt:25.1
>>
>> This one has the advantage of being more flexible, but less robust  
>> to the introduction of new units (as they can't be advertised using  
>> Accept-Ranges).
>
> One of the issue for the first case is when smpte is used, as the  
> beginning of the resource might not be zero. In that case, it would  
> be hard to define the duration in the Content-Range: case.
> Jack, Davy, what's your opinion on this?


I'm in favor of the simple solution, i.e.

	Content-Range: smpte-30-drop 1:22:33-2:33:44.1/4:00:00

There seems to be little added value in allowing mixing of time  
formats (everyone: please speak up if you think there is), and aside  
from the Accept-Ranges advertisement it would break there's also the  
burden of more difficult parsing.
--
Jack Jansen, <Jack.Jansen@cwi.nl>, http://www.cwi.nl/~jack
If I can't dance I don't want to be part of your revolution -- Emma  
Goldman





Received on Thursday, 10 September 2009 14:05:52 GMT

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