[AG-TECH] AccessGrid 3: What information is available

Andrew Rowley Andrew.Rowley at manchester.ac.uk
Tue May 24 06:36:02 CDT 2005


The ScreenStreamer code (http://www.memetic-vre.net/software/ScreenStreamer)
at one point in the development cycle had some features that would allow it
to be a vic/rat replacement.  This is Java code using Java Media Framework,
so it is already platform independent.  If you have used this, you will
notice that the interface already looks a bit like vic.  This has been
slimmed down to only support screen sending, but it would not take much work
to add the video sending back in.  It also had some support for audio
transmission and reception so this would allow audio and video from one

>From what I remember, the main problems were that 
a) The H.261 encoder is a bit slow as I wrote this from scratch and have not
spent much time on it
b) JMF doesn't include the AG audio codec so this would need implementing.
This should not be very hard given that AG audio is uncompressed as far as I

JMF already has H.261 video decoding, and Java video encoding and decoding
for better quality than H.261.  The framework is quite nice in that JMF
handles most of the RTP things, and you can just plug in new codecs as they
are written.

Just a suggestion - if anyone wants the ScreenStreamer code to look at, let
me know and I will arrange access.

Andrew :)

Access Grid Support Centre,
RSS Group,
Manchester Computing,
Kilburn Building,
University of Manchester,
Oxford Road,
M13 9PL, 
Tel: +44(0)161-275 0685
Email: Andrew.Rowley at manchester.ac.uk 

> -----Original Message-----
> From: owner-ag-tech at mcs.anl.gov [mailto:owner-ag-tech at mcs.anl.gov] On
> Behalf Of Steve Smith
> Sent: 24 May 2005 09:15
> To: Rhys Hawkins
> Cc: barz at nchc.org.tw; ag-tech at mcs.anl.gov
> Subject: Re: [AG-TECH] AccessGrid 3: What information is available
> > Agreed! Parts of VIC/RAT are worth reusing (eg libcommon) but I think
> > its time to get rid of the TCL/TK reliance. I think there is enough
> > people working in the area of video tools for the AccessGrid to start
> > a community development aimed a replacing VIC in the AG.
> I agree with this in principle, but that will take some time and while
> that effort is taking place we need knock the worst of the issues out of
> current tools (redirecting your efforts to a new implementation while
> ignoring the existing is always disaster, Joel Spolsky has written about
> this extensively).
> In particular I think the following would be major leaps forward in
> usability:
>         * Being able to change the venue in Vic and Rat without
>         restarting them
>         * Multiple video inputs to Vic (which would remove the necessity
>         of multi-machine nodes)
> Cheers,
> Steve

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