CAIRN Conferencing


Last update: Wed 15th Apr 1998

Multicast conferencing can be performed on many different architectures; this page lists software available for the most common conferencing platforms on CAIRN: FreeBSD, Solaris and SunOS. If you need information about other architectures, let me know.


Basic Conferencing Software

For conferencing, you'll need an audio tool, a video tool and a whiteboard. Audio tools include vat from LBNL and rat from UCL, for video we use vic, and for a whiteboard we use wb from LBL. You might also want to obtain the NTE shared editor, but we don't currently use it much. You'll also need the sdr session directory to join sessions. These preferences may change over time as new software (particularly MASH from UCB) becomes available.

Software below is listed as "stable" or "experimental". You should be running versions of the software at least as recent as the stable versions. Running experimental software is optional, but as experimental software becomes more stable, you may not be able to participate in all activities with the stable versions.

To participate in CAIRN conferences, sdr must be configured with the CAIRN admin scope information. Add the following to your ~/.sdr/sdr.tcl file (create the file if it doesn't exist):

add_admin CAIRN 239.140.173.255 9874 239.140.173.0 24 63
This tells sdr to listen on 239.140.173.255/9874 for CAIRN scoped announcements, that the CAIRN scope is 239.140.173.0/24, and that the default TTL is 63.

Stable Software

The list below represents the latest versions of the software that I'm aware of and that are stable. Where older versions are mostly OK, I say so.

Solaris: stable recommendations

For video capture, the SunVideo card is recommended on Sbus-based machines. No-one I know has tried conferencing on PCI-based machines, but Sun are selling a PCI SunVideo card, and some other cards also seem to be available.

If you have a Vigrapix card, there is a driver for solaris, but it can cause your machine to hang. Use it at your own risk! Vigra won't give it to you anymore...

To display video, you'll want to increase the size and number of shared memory segments. Add the following lines to /etc/system and reboot:

* for vic
        set shmsys:shminfo_shmseg=20
        set shmsys:shminfo_shmmax=2097152

Applications


SunOS4: stable recommendations:

For video capture, no really great card exists. The Vigrapix is probably the best of the options that do work if you can still get one. There are probably still Sun Videopix cards out there, although they're really slow. Parallax cards are quite quick, but are expensive, need a capture window to be displayed continuously, and the Parallax X server is rumoured to cause the machine to crash occasionally.

Applications


FreeBSD: Current recommentations:

If you want to use FreeBSD for conferencing, I strongly recommend FreeBSD 2.2.6-RELEASE (or later). Luigi Rizzo's audio driver is in 2.2.6-RELEASE. If you wish to run earlier versions, you'll need to get the audio driver patches from Luigi and include it yourself.

Everything else is somewhat dependent on the hardware you end up with. I recommend the Haupauge Wincast/TV (BT-848 based) video capture card, and the A/Open AW35Pro audio card. My audio card produces unacceptable noise on the mic input, but the line input works well and a cheap Radio Shack mixer makes a fine pre-amp - Brad Karp's card doesn't have this problem. The Matrox Meteor has also seen quite a bit of use on CAIRN, but doesn't seem to be available anymore. Unlike the BT-848 based cards, this has an S-Video input, so should produce slightly higher quality at slightly greater cost. However, in practice it seems that the camera quality and lighting levels are much more important than the capture card.

Next, build yourself a multicast and audio enabled kernel. It's advisable to include the following in addition to the normal stuff you want:

#allow configuration of PnP cards
options         USERCONFIG              #boot -c editor
controller pnp0
#allow multicast routing (only if you need to run mrouted)
options         MROUTING
#enable the sound driver
device pcm0 at isa ? port? tty irq 5 drq 1 flags 0x13 vector pcmintr
#enable the Brooktree BT848 video capture card driver
device bktr0
#shared memory
options SYSVSHM
options "SHMMAXPGS=16384" # allow lots of memory for vic
options "SHMMNI=128" # allow lots of segments for vic
options "SHMSEG=32" # allow lots per process for vic
Actual configuration will depend on your machine. If you're using a different audio card, check out the instructions that come with Luigi's audio driver patches. You do not want to include "device snd0" or the kernel won't build. You also want to make sure that /dev/audio gets created (it's a link to /dev/audio1 on my machine), and if you're using at BT848 capture card, that /dev/meteor0 gets created (it's a link to /dev/bktr0 on my machine).

Applications


Experimental Software

Experimental software we plan to use on CAIRN: I'll include more information on these in due course...
Page maintained by Mark Handley