- From: Davy Van Deursen <davy.vandeursen@ugent.be>
- Date: Tue, 03 May 2011 13:12:39 +0200
- To: Media Fragment <public-media-fragment@w3.org>
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. 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 11:13:11 UTC