Subject: [MMUSIC] RTSP: RTP-Info syntax (2326bis09)

From: "Jae-Hwan Kim" <[email-masked]>
Date: Wed, 2 Mar 2005 00:19:56 +0900

Dear experts,

Recently, I found some weird RTP-Info strings in a commercial RTSP
server.

RTP-Info:url=rtsp://example.com/foo/audio

RTP-Info:

According to 2326bis09 RTP-Info syntax(I am very happy with the new ABNF
syntax, 

which is much clear than before ;-> ), the above seem to be wrong and I
am fine, anyway.

But I could know the following cases are possible:

Case1) RTP-Info:url=rtsp://example.com/foo/audio;seq=45102

Case2) RTP-Info:url=rtsp://example.com/foo/audio;rtptime=12345678

What does this mean? Are they meaningful?

Best Regards,

Jae-Hwan

------------------------------------

Software Architect/Streaming Platform

Nextreaming Corporation

[email-masked]

5th Fl. Gangnam Metro Bldg., 1339-9, 

Seocho-Dong, Seocho-Gu, Seoul 137-070, Korea

tel: +82.2.2194.5361

mobile: +82.17.225.0619

------------------------------------

_______________________________________________
mmusic mailing list
[email-masked]
https://www1.ietf.org/mailman/listinfo/mmusic

---

From: Magnus Westerlund <[email-masked]>
Date: Tue, 01 Mar 2005 16:57:22 +0100

Hi,

I think you have stumbled on an issue in the ABNF syntax. The current 
syntax:

    RTP-Info        =  "RTP-Info" HCOLON rtsp-info-spec
                       *(COMMA rtsp-info-spec) CRLF
    rtsp-info-spec  =  stream-url 1*ri-parameter

Requires that in addition to the URI, that also at least one parameter 
is present. However the new RTP-Info text does not require either of the 
parameters to be present. However due to this there is the question what 
to do:

A) Do not provide any RTP-Info for that media stream that one do not 
have at least one parameter to provide.

B) Allow that only the URL is present but no parameters with sync 
information.

Any opinions on which to use?

> RTP-Info:url=rtsp://example.com/foo/audio

This is against the current syntax. It is also the most likely against 
the old erroneous syntax.

> RTP-Info:
This is definitely not allowed in either the new or old syntax. In this 
case the header shall not be present at all.

Cheers

Magnus Westerlund

Multimedia Technologies, Ericsson Research EAB/TVA/A
----------------------------------------------------------------------
Ericsson AB                | Phone +46 8 4048287
Torshamsgatan 23           | Fax   +46 8 7575550
S-164 80 Stockholm, Sweden | mailto: [email-masked]