RE: [MMUSIC] video media control draft

["Even, Roni" <[e-mail]>]

Hi,
I understand the need for asking for frame rate and frame size since these
are absolute numbers and that is why we have the media control draft and I
will add the support for per payload type.
As for the quality how do you define that in absolute terms, isn't it
something that is an application or codec specific. Is someone using the
quality attribute in SDP and if yes what are the user expectations when he
ask for higher quality comparing to lower quality.How does the encoder use
this parameter, one way to get "high quality" is by reducing the frame rate
or resolution at the same line rate but this can be controlled by those
attributes. At least in this case the receiver can say what he is willing to
scarifies (frame rate or resolution) to get higher quality
Thanks
Roni Even

 
 
 -----Original Message-----
From: Andreas Kassler [mailto:[e-mail]]
Sent: Tuesday, August 13, 2002 10:49 AM
To: Sanjoy Sen; 'Even, Roni'; 'Nils Henrik Lorentzen'; [e-mail]
Subject: Re: [MMUSIC] video media control draft



Sanjoy et al,
we were also concerned about the expressability of quality attributes that
defines the quality of service at application level for a given video(audio)
stream. 
In draft-guenkova-mmusic-e2enp-sdpng-00.txt we basically have identified a
requirement
to ... introduce (per) codec parametrization attributes like frame-rate,
frame-size, color-
quality-range, overall-quality-range, etc. which should be  uniquely
interpreted by the end-systems.
 
When it comes to negotiation of such attributes with the peer for setting up
quality enhanced
media streams, we propose to specify such parameters on a per codec basis.
The reason is 
that not all codecs support all combinations of such parameters. For example
with a given
hardware, a sender may be able to compress at 25 fps at CIF a H.261 stream
but may
not be able to compress at 25 fps at CIF a MPEG-4 stream due to limited
resources.
 
We propose also to work on these issues within the SDPng context.
 
-Andreas

----- Original Message ----- 
From: Sanjoy Sen <mailto:[e-mail]>  
To: 'Even, Roni' <mailto:[e-mail]>  ; 'Nils Henrik
<mailto:[e-mail]> Lorentzen' ; [e-mail]
<mailto:[e-mail]>  
Sent: Tuesday, August 13, 2002 1:55 AM
Subject: RE: [MMUSIC] video media control draft



I saw this pretty old thread. I do support proposing frame-size on a per
codec (payload-type) basis. I would also like to throw in the requirement
that we need to be able to specify the preferred media qualities (e.g., in a
scale of 0-10) per payload-type (right now SDP defines a quality attribute
per m line). Thoughts?

Does it make sense to encode all these information as part of an "fmtp"
attribute for the payload-type? - e.g., a:fmtp:<PT> res=QCIF/quality=5

-Sanjoy 

> -----Original Message----- 
> From: Even, Roni [ mailto:[e-mail]
<mailto:[e-mail]> ] 
> Sent: Wednesday, August 07, 2002 1:21 AM 
> To: 'Nils Henrik Lorentzen'; [e-mail]; Even, Roni 
> Subject: RE: [MMUSIC] video media control draft 
> 
> 
> Nils, 
> I think your suggestion makes sense. I will update the draft Roni 
> 
> > -----Original Message----- 
> > From: Nils Henrik Lorentzen [ mailto:[e-mail]
<mailto:[e-mail]> ] 
> > Sent: Tuesday, August 06, 2002 10:35 AM 
> > To: [e-mail]; Even, Roni 
> > Subject: Re: [MMUSIC] video media control draft 
> > 
> > 
> > On Tuesday 06 August 2002 07:59, Even, Roni wrote: 
> > 
> > > Hi Petri, 
> > > In my draft draft-even-mmusic-video-media-control-00.txt, 
> I have a 
> > > video-resolution attribute that allow to specify the 
> > maximum frame rate 
> > > supported per resolution. 
> > 
> > A difference between your draft and 
> > draft-koskelainen-sdp263-02.txt is that 
> > in the latter you may specify resolutions and options per 
> > payload type, 
> > instead of per media line. I think this is more flexible, and 
> > would suit our 
> > needs better. Any particular reason for having it per media-line ? 
> > 
> > In your draft it would be a simple change to make it per payload: 
> > a=video-resolution:<size> to 
> > a=video-resolution: <payload no> <size> 
> > or possibly 
> > a=video-resolution: [ PT=<payload no>] <size> 
> > ie payload no is optional, so if not specified the 
> > resolutions would apply to 
> > all the payload types on the media line. 
> > 
> > > In the meeting this attribute was accepted for 
> > > SDP. I could not find the draft mentioned 
> > "draft-koskelainen-sdp263-02.txt" 
> > 
> > It expired quite some time ago, but can be found at: 
> > http://www.dmn.tzi.org/ietf/mmusic/sdp-ng/input/draft-koskelai
<http://www.dmn.tzi.org/ietf/mmusic/sdp-ng/input/draft-koskelai>  
> > nen-sdp263-02.txt 
> > 
> > Nils Henrik Lorentzen 
> > 
> 
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