[MMUSIC] Request URI with query and control URI

[Magnus Westerlund <magnus.westerlund at ericsson.com>]

Hi,

Christian logged the following ticket at source forge:
https://sourceforge.net/tracker2/?func=detail&aid=2038449&group_id=23194&atid=377747
> 
> Current client implementations append the (relative) control URI at the end of the request URI. If the request URI contains a query, the results are difficult to parse;
> 
> Example:
> Request URI:
> rtsp://server:554/greetings/?person=Bob
> Controls (in SDP) for audio and video streams:
> a=control:voice_audio
> a=control:front_image
> 
> Current result:
> rtsp://server:554/greetings/?person=Bob/voice_audio
> -> problems parsing URI (person := "Bob/voice_audio")

This is not following the relative reference rules specified in RFC
3986. What I understand the correct processing result would be:

rtsp://server:554/greetings/voice_audio

The query is not maintained from the Base URL if there is a path
component present in the relative one.

So in fact maintaining the URI query component requires one to copy it
into the relative reference, i.e.

rtsp://server:554/greetings/?person=Bob
Controls (in SDP) for audio and video streams:
a=control:voice_audio?person=Bob
a=control:front_image?person=Bob

Which when processed would result in:

rtsp://server:554/greetings/voice_audio?person=Bob

> 
> Possible alternative:
> rtsp://server:554/greetings/voice_audio/?person=Bob
> -> might have even more problems (/greetings/voice_audio/ results in 404
> or query not understood)
> 
> Proposal:
> rtsp://server:554/greetings/?person=Bob#voice_audio
> 
> Fragments are currently not defined (allowed) for messaging between client and server and one stream of several within a presentation could be seen as 'fragment' of the presentation.
> 

Yes, because they are client local instructions. For RTSP the most
logical fragment extension is format that specifies where to start to
play. So if you embedded a URI with a fragment of this type in a webpage
the RTSP client that deals with the URI would use the fragment to to
construct a range header to request the start time.

> If fragments are not going to be the solution, please provide examples
> and/or definitions on how to apply and parse the control URI.

No, I don't want to mess with the standard URI parsing rules. Although
they are problematic in this case.

Cheers

Magnus Westerlund

IETF Transport Area Director & TSVWG Chair
----------------------------------------------------------------------
Multimedia Technologies, Ericsson Research EAB/TVM
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