Subject: Re: ISDN, Mbone gateway

From: Soghra Zamani <[email-masked]>
Date: Mon, 10 Feb 1997 10:36:49 +0000 (GMT)

Hi,

Thanks to all of you who replied to my original query. I think perhaps I
wasn't very clear in my e-mail. What we want to do is to get the output
from our codec that is sent to the ISDN to be sent to a machine that is
multicast capable(i.e. running mrouted) and can send this output to the 
mbone.

I think dauphin's reply was probably the most accurate one, but I am
still not sure how we can translate the input to the isdn card in a sun 
box to mbone application output on the ethernet card or even if such a 
thing is possible. 

Please reply if you have any idea how this can be done.

Thanks in advance,

Soghra
 
---------------------------
Soghra Zamani
e-mail: [email-masked]
Tel: +44 (0)171 753 3214
---------------------------

---

From: Craig Tenney <[email-masked]>
Date: Mon, 10 Feb 97 11:10:44 -0800

Soghra,

> box to mbone application output on the ethernet card or even if such a 

If I understand correctly, then you are attempting to do the same thing
we are.  You want to build a gatway from your ISDN based videoconferencing 
system to the mbone.

It is easy if you are just trying to build a one-way feed from the ISDN 
Codec to the mbone.   You just need to connect the video out on your codec 
with the video in on any video capture card supported by the mbone tools and 
the audio out to the line in on the workstation, and then run the mbone 
tools on that workstation.

It is more difficult to get the mbone video feed back to the ISDN codec.
This is what we want to do for our ISDN Video conferencing to mbone gateway.

We had such a gateway working in test mode using a DEC 3000/300LX with
two J300 cards.  The vic utility is capable of sending the mbone feed
to the video out on the J300, so we connected the video out on the J300
with the video in on our codec.  This provided the path from the mbone 
back to the ISDN videoconferencing system.

This gateway would work quite well for 5-10 minutes before the jv2driver 
would leak enough memory to crash the system.  I asked Lance Berc from DEC, 
who wrote the jv2driver, about this and he said that he is no longer making 
improvements to the jv2driver since the recomended path was to use the 
mmeserver instead of the jv2driver on DEC workstations.

So we scraped the old gateway and are now attempting to build a new one
using a DEC AlphaStation 255/233, with AV321 cards, and DEC's mmeserver.  

The problem is that vic does not support the video out port on the
AV321 card so instead we decided just to display the vic window on
the screen and convert the screen to NTSC using a VGA to NTSC converter.
This resulted in an image that we could feed back to the Codec, but
we are not very happy with the quality of that image.

If anyone on the list has any other ideas on how to get a better video 
stream from the mbone I would welcome them.  Apparently, vic supports the 
video out on one of the SGI frame capture cards, but from what I've heard, 
the performance on the card is not very good.

Craig Tenney
[email-masked]