- From: Davy Van Deursen <davy.vandeursen@ugent.be>
- Date: Tue, 03 May 2011 13:43:22 +0200
- To: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
- CC: Media Fragment <public-media-fragment@w3.org>
Silvia, On 3/05/2011 13:28, Silvia Pfeiffer wrote: > 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? Ok, for this example, sending the content duration would work. But consider an example for the track dimension: media.webm#track=foo where foo does not exist in the source media. The behaviour in this case is to ignore the non-existing track fragment and thus playing the entire media resource. This means that after receiving a 416, the UA must request the entire resource ... Best regards, Davy -- 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 11:43:56 UTC