[AG-TECH] Question about Codec
Osland, CD (Chris)
C.D.Osland at rl.ac.uk
Wed Aug 6 10:46:15 CDT 2003
Can I pick up on the idea of
"> i think allowing for varying levels of bandwidth capability
> of different sites
> to allow more people to participate is a different challenge
> that should be
> addressed independently."
As far as I am aware, this would be an enormous challenge [but
I'd love to find out it's already been tackled!]
Let me demonstrate through a scenario currently playing out in
the UK. A high percentage of the academic community have connection
at serious bandwidth to SuperJanet 4 - say 650 Mbaud or more. Quite
a lot of the smaller research institutes may only have 2 or 8 Mbit
and are currently looking for the money to upgrade to 34 Mbit or
more. Bandwidth costs in the UK!
At a completely parochial level, I do 40% of my work located at
RAL (Gbit or more connection) and 60% at my father's house
(128 Kbit/sec ISDN 2B+D). Even there I would love to join in
on AG events, at least contributing my video stream, and maybe
seeing a chairman, if there is one. At present I could only do
this either by killing off video completely, or by going via dial-up
audio only into the AP10 at (say) RAL.
AFAIK, there is no way to select which video streams should go
to any site if they are multicast, thereby saving inbound bandwidth.
The requirement as I see it is for a given site to say that it is
not interested in receiving particular streams (rather than the
opposite which would be for a site to be able to restrict the
sites it is sending to).
I don't know whether anyone has had thoughts on this; I do realise
that the main point of the AG is that everyone sees everyone else
and this is a facility that is in the opposite direction!
Cheers
Chris
____________________________________________________________________
Chris Osland Office tel: +44 (0) 1235 446565
Digital Media and Access Grid Medialab tel: +44 (0) 1235 446459
BIT Department Access Grid room tel: +44 (0) 1235 445666
e-mail: C.D.Osland at rl.ac.uk Fax: +44 (0) 1235 445597
CLRC Rutherford Appleton Laboratory (Bldg. R18)
Chilton, DIDCOT, Oxon OX11 0QX, UK
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> -----Original Message-----
> From: Gurcharan.S.Khanna at Dartmouth.EDU
> [mailto:Gurcharan.S.Khanna at Dartmouth.EDU]
> Sent: 06 August 2003 16:16
> To: bdr at internet2.edu; judson at mcs.anl.gov
> Cc: dwkim at cosmos.kaist.ac.kr; ag-tech at mcs.anl.gov
> Subject: Re: [AG-TECH] Question about Codec
>
>
> hi,
>
> i'd like to second what bob would like to do with DVTS. using
> DV is really
> great because there is no codec involved, no compression needs to take
> place. the DV stream is simply packetized and sent out and
> the receiving
> system just has to render the DV stream which doesn't seem to take
> much cpu power at all. literally, all one needs is a firewire
> DV cam and a
> pc with firewire in and free software. it can't get much
> easier and cheaper
> than that. [i've been running a multicast DV stream reliably
> for the past 6
> months or so. and now hardware cards are available as well]
>
> now all we need is the multicast user interface and we have DV quality
> video and audio in an AG setting. of course, some will say
> that 30Mbps is
> too big a penalty to pay for this simplicity. but big
> bandwidth should be a
> non-issue for us; at least it should be a challenge and not a
> thing to avoid.
> i think allowing for varying levels of bandwidth capability
> of different sites
> to allow more people to participate is a different challenge
> that should be
> addressed independently.
>
> just my opinion,
>
> -gurcharan
> ===========================
> Gurcharan S. Khanna, Associate Director
> Research Computing, Dartmouth College
> gkhanna at dartmouth.edu
> office: 603-646-1644
> http://research.dartmouth.edu/
> http://www.dartmouth.edu/~gkhanna
>
> --- Bob Riddle wrote:
> I guess I might as well confess I'm hoping to do some DVTS
> work before
> the end of the year ...
>
> Ivan R. Judson wrote:
>
> >Additionally, we are looking into higher quality codecs, both Larry's
> >OpenMASH and some other more informal work hopefully
> involving Colin and Co
> >at ISI. OM has a new H.263 codec that works very nicely, but
> the current
> >agvic has a bug that causes it to crash when it sees an OM
> H.263 stream, OM
> >also has as bob pointed out MJPEG support.
> >
> >The other work involves potentially taking recently
> available prosumer
> >cameras that produces a MPEG2-TS stream via firewire at HD
> resolutions (so
> >the specs say :-), grabbing the data and streaming via vic
> shouldn't be
> >insurmountable; decoding might take a bit of horsepower, but
> at least it's
> >MPEG2 (decoders for which are seemingly embedded in most
> graphics chips
> >now).
> >
> >Another place to consider looking it Linux Media Labs MPEG-4
> boards, with
> >drivers for mplayer. We don't have this working, but would
> be happy to help
> >you make it work.
> >
> >Cheers,
> >
> >--Ivan
> >
> >
> >
> >>-----Original Message-----
> >>From: owner-ag-tech at mcs.anl.gov
> >>[mailto:owner-ag-tech at mcs.anl.gov] On Behalf Of Bob Riddle
> >>Sent: Wednesday, August 06, 2003 8:11 AM
> >>To: dwkim
> >>Cc: ag-tech at mcs.anl.gov
> >>Subject: Re: [AG-TECH] Question about Codec
> >>
> >>
> >>If you use the openmash vic, you can use RtpTV to generate
> >>mjpeg streams that the openmash vic will interpret. You'll
> >>need very capable cpus on the AG display machine.
> >>
> >>dwkim wrote:
> >>
> >>
> >>
> >>>Hi all:
> >>>
> >>>We are wondering that there is any other codec not h.261
> >>>for example, Can We use DVTS(digital video transport system)
> >>>
> >>>
> >>or HDTV in
> >>
> >>
> >>>AccessGrid ?
> >>>
> >>>Thanks for any information
> >>>
> >>>Daewon kim
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >>--
> >>Bob Riddle (bdr at internet2.edu) Technologist,Internet2
> >>3025 Boardwalk, Suite 100 Ann Arbor, Michigan 48108
> >>Business Phone: 734.913.4257 Fax Number: 734.913.4255
> >>
> >>"Opportunity is missed by most people because it is dressed
> >>in overalls and looks like work" Thomas Edison
> >>
> >>
> >>
> >>
> >>
> >
> >
> >
> >
>
> --
> Bob Riddle (bdr at internet2.edu) Technologist,Internet2
> 3025 Boardwalk, Suite 100 Ann Arbor, Michigan 48108
> Business Phone: 734.913.4257 Fax Number: 734.913.4255
>
> "Opportunity is missed by most people because it is dressed
> in overalls and
> looks like work" Thomas Edison
>
>
>
> --- end of quote ---
>
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