Subject: [MMUSIC] Re: [AVT] What should be the implementation for PAUSE for realtime RTSP/RTP server

From: Magnus Westerlund <[email-masked]>
Date: Tue, 16 Sep 2003 09:04:07 +0200

Hi Deepak,

If you have a RTSP server for a media that is "live", i.e. not stored 
the PAUSE still has an important purpose. That is to halt media delivery 
from the server. In this scenario one uses PLAY to start delivering 
media packets from the current position in the live feed, when a PAUSE 
request is received one halts the delivery.

Technically from a client side on can do the same by using TEARDOWN, 
however if the intent was to temporally halt deliver that method will 
cost one extra RTT when restarting as it will require SETUP and PLAY.

Please note that a RTSP server MUST implement the PAUSE method when 
supporting basic playback services.

Cheers

Magnus

Deepak Kotian wrote:

> Hi.
>  
> 
> What should be the implementation for PAUSE for realtime RTSP/RTP server.
> 
> We stream like TV shows or DVDs or Camera, in this case , what
> 
> PAUSE implementation should be there on RTSP server. Is it really needed ?
> 
> Can anyone give any view on this please.
> 
>  
> 
> Thanks and Regards
> 
> Deepak
> 

-- 

Magnus Westerlund

Multimedia Technologies, Ericsson Research EAB/TVA/A
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From: Deepak Kotian <[email-masked]>
Date: Tue, 16 Sep 2003 23:20:09 +0530

Thanks Magnus, we had the same in mind.
But, somehow it did work fine with RealOne.
Will check it again.
What are kind of queries we can post in this forum, could
you please let us know.
Thanks again.

Thanks and Regards
Deepak

----- Original Message -----
From: "Magnus Westerlund" <[email-masked]>
To: "Deepak Kotian" <[email-masked]>
Cc: "IETF MMUSIC WG" <[email-masked]>
Sent: Tuesday, September 16, 2003 12:34 PM
Subject: Re: [AVT] What should be the implementation for PAUSE for realtime
RTSP/RTP server

---

From: Magnus Westerlund <[email-masked]>
Date: Wed, 17 Sep 2003 10:29:52 +0200

Hi,

The MMUSIC working group, and as being part of IETF, has a charter that 
can be found here:
http://www.ietf.org/html.charters/mmusic-charter.html

Discussion on work items that are part of the WG charters and possible 
future work are what the list is intended to discuss. When it comes to 
RTSP, for which the specification is progress of being updated, the 
discussion should primarily be on issues regarding the updated 
specification. This can be things that are unclear in RFC 2326 which has 
not yet be addressed. Any contribution with comments and opinions are 
desired, however I would recommend that you try to catch up on the work 
already done.

The latest updated specification is:
http://www.ietf.org/internet-drafts/draft-ietf-mmusic-rfc2326bis-04.txt
However this specification is still behind a lot of the resolved items. 
The known RTSP bugs are kept track on in a SourceForge project that can 
be found here:
http://rtspspec.sourceforge.net/

We have had a rather many teleconferences during the almost two years 
since this work started. The agenda and minutes for these can be found at :
http://rtsp.org

The discussions on mail in this work has taken place on this mailing 
list and can be found in the mailing lists archive accessible from here:
https://www1.ietf.org/mailman/listinfo/mmusic

So you may ask about interpretations off how to implement things, 
however I expect you to make the homework before and look if it is 
already explained, discussed, resolved. If you don't agree with the 
result you may reopen the discussion, but I hope that this is not so 
necessary.

Best Regards

Magnus

-- 

Magnus Westerlund

---

From: Deepak Kotian <[email-masked]>
Date: Wed, 17 Sep 2003 23:53:18 +0530

Hi,

Can one please let us know
What should be the implementation for the parameter like SMPTE Relative
Timestamps/Normal Play Time/Absolute Time in the our RTSP server.

Our requirement is to implement the minimal RTSP server for a RealTime
Video data and play it on RealOne player.
We stream like TV shows or DVDs or Camera, in this case , it is basically
RealTime video

Can anyone please give any view on this please.

Thanks and Regards
Deepak

---

From: Deepak Kotian <[email-masked]>
Date: Wed, 17 Sep 2003 23:39:59 +0530

Hi Magnus,

Thanks very much for the good information.

Thanks and Regards
Deepak

----- Original Message -----
From: "Magnus Westerlund" <[email-masked]>
To: "Deepak Kotian" <[email-masked]>
Cc: "IETF MMUSIC WG" <[email-masked]>
Sent: Wednesday, September 17, 2003 1:59 PM
Subject: Re: [MMUSIC] Re: [AVT] What should be the implementation for PAUSE
for realtime RTSP/RTP server

---

From: Magnus Westerlund <[email-masked]>
Date: Thu, 18 Sep 2003 10:43:59 +0200

Hi,

What Range format to use depends on what time format things are 
interesting to give, but also on the clients capabilities. Not knowing 
what your intentions are I can't give any answers.

NPT is required to be implemented in clients. If no frame exact times 
since media start is of interest I would use this format.

SMPTE is good if one needs to have frame exact access, however how many 
clients that support this is a big question.

Absolute time is good if you are relying things that has interesting 
real time clocks. For example a surveillance tape which is stamped with 
the time of capture should be using absolute time.

Best Regards

Magnus

-- 

Magnus Westerlund

---

From: Deepak Kotian <[email-masked]>
Date: Fri, 19 Sep 2003 00:59:10 +0530

Hi ,

When we check this with RealOne.
When we say PAUSE at realone, we get a PAUSE request on
the server and we stop the RTP packets delivery and then when we give
a PLAY request from RealOne, the server gets the Request and
we start the delivery of RTP packets as well, but we could
play only the 3/4 seconds video which is in the buffer at the RealOne
client, but later the movie freezes on the Client side.
We are sourcing the PTS from the MPEG1 Elementary headers and
we get the MPEG1 stream realtime from our Encoder cards which
stream via RTP/RTCP.

Could you please some more details if possible.

Thanks and Regards
Deepak

----- Original Message -----
From: "Magnus Westerlund" <[email-masked]>
To: "Deepak Kotian" <[email-masked]>
Cc: "IETF MMUSIC WG" <[email-masked]>
Sent: Tuesday, September 16, 2003 12:34 PM
Subject: Re: [AVT] What should be the implementation for PAUSE for realtime
RTSP/RTP server