- From: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
- Date: Tue, 3 May 2011 21:28:54 +1000
- To: Davy Van Deursen <davy.vandeursen@ugent.be>
- Cc: Media Fragment <public-media-fragment@w3.org>
On Tue, May 3, 2011 at 9:12 PM, Davy Van Deursen <davy.vandeursen@ugent.be> wrote: > Dear all, > > another topic related to the test case discussions ... > > The issue is about the case where we have an invalid media fragment URI, but > that invalidity is only detectable by the UA if it has information regarding > the source media (see [1] in the spec). For example: media.webm#t=15 and the > duration of media.webm is only 10s. > > Suppose we have a smart UA (i.e., scenario described in [2], only byte range > requests are used). The smart UA is able to determine the duration of the > media, interprets the media fragment URI, and seeks to the end of the media > (as discussed in [3]). > > So far so good, but what happens when we have a UA using a media > fragments-enabled server (i.e., scenario described in [4], where time ranges > are used)? The UA does not know the duration of the source media. Therefore, > it just sends an HTTP Range request to the server: > > GET media.webm HTTP/1.1 > Range: t:npt=15- > > Since the requested time range is invalid, the server answers with a 416 > (Requested Range Not Satisfiable), and the UA still doesn't have a clue > about the duration of the media. An intelligent server should inform the UA with every request about the content duration, even if it is an error, shouldn't it? Silvia. > So the question is, what is the behaviour of a UA getting a 416 from a Media > Fragments-enabled server (especially in the case when the decoding pipeline > is not setup)? > > I think this situation must be clarified in the spec. > > Best regards, > > Davy > > [1] > http://www.w3.org/2008/WebVideo/Fragments/WD-media-fragments-spec/#error-media > [2] > http://www.w3.org/2008/WebVideo/Fragments/WD-media-fragments-spec/#processing-protocol-UA-mapped > [3] > http://lists.w3.org/Archives/Public/public-media-fragment/2011Apr/0054.html > [4] > http://www.w3.org/2008/WebVideo/Fragments/WD-media-fragments-spec/#processing-protocol-Server-mapped > > -- > Davy Van Deursen > > Ghent University - IBBT > Department of Electronics and Information Systems - Multimedia Lab > URL: http://multimedialab.elis.ugent.be/dvdeurse > >
Received on Tuesday, 3 May 2011 11:29:41 UTC