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Re: Format of RTSP URLs

From: Roy T. Fielding <fielding@kiwi.ics.uci.edu>
Date: Tue, 15 Jul 1997 11:03:09 -0700
To: Rob Lanphier <robla@prognet.com>
cc: www-talk@w3.org, uri@bunyip.com, confctrl@isi.edu
Message-ID: <9707151114.aa06322@paris.ics.uci.edu>
>I think this may be acceptable, but there's one other possible requirement
>I'd like to mention.  It would be nice to have the ability to have relative
>URLs, so that, for example, the following scenario can play out (using ":"
>as a server side fragment identifier for the time being)
>
>C->S  DESCRIBE rtsp://foo/db/moviebase?movie=twister RTSP/1.0 1
>
>S->C  RTSP/1.0 200 1 OK
>      Content-length: 178
>      Content-type: application/sdp
>
>      s= sample rtsp presentation
>      r = rtsp://foo/db/moviebase?movie=twister   /* aggregate URL*/
>      m= audio 0 RTP/AVP 0
>      r = :track=audio1                           /* URL to control audio*/
>      m=video 0 RTP?AVP 26
>      r = :track=video1                           /* URL to control video*/
>
>At this point, the client can easily discern that the audio track and the
>video track are indeed merely fragments of the same object on the server,
>and not separately controlled entities.  I'm not sure how this would work
>with ";" parameters, since the relative behavior defined in 1808 is
>different than what I'd expect above (which is more akin to "#").

Those relative URLs would resolve to

      rtsp://foo/db/:track=audio1
      rtsp://foo/db/:track=video1

which is obviously not what you would want.  Query info and relative
references do not mix in practice.  In any case, using query info to
select a resource, as opposed to redirecting to the real resource URL,
is poor namespace management.

....Roy
Received on Tuesday, 15 July 1997 14:21:04 GMT

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