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2004-11-19

Broadcasting using iSight and Quicktime Broadcaster

NB this still seems flakey (ie it works sometimes but not reliably). Use at your own risk...

Preliminaries

These instructions assume you have an iSight camera, and have downloaded and installed Apple's QuickTime Broadcaster. Register to get an account on the University Darwin Streaming Server. You will be given FTP access to pilton.ucs.ed.ac.uk—the reflector which will braodcast your video stream.

Setting up a live broadcast

Plug in the iSight; quit from iChat; launch QuickTime Broadcaster.

Check the IP address for pilton.ucs.ed.ac.uk
(type host pilton.ucs.ed.ac.uk on the unix command line).

In the quicktime broadcaster window, select multicast transmission, and enter the reflector (i.e. pilton) IP 129.215.16.20 for both audio and video address. Don't change the port entries.

Under Audio, enable the audio stream and select the source (probably iSight) and set parameters; under Video enable the video stream, select source (iSight) and parameters. (Note that the University reflector is throttled at 350kbits/sec total for both streams, so 300kbits/sec is about the most you can use for video.)

Now choose File>>Export>>SDP... from the file menu. This produces an sdp file. Save it somewhere convenient (eg. as test.sdp) and then transfer it to the reflector (pilton.ucs.ed.ac.uk) by ftp.

You can save the Broadcast Settings at this point, quit QuickTime Broadcaster, and come back later to give your performance.

Launch Quicktime Broadcaster; Click the broadcast button to go on air, and tell your audience to watch the stream with QuickTime Player (File>>Open URL in New Player...) using a URL like rtsp://pilton.ucs.ed.ac.uk:554/hcs/test.sdp (see your email from ucs which gives details of the URL to your space on pilton). Unfortunately, both Safari and Firefox try and open this URL using Real Player - which doesn't cope with the format.

2004-05-04

sshLogin ssh-agent ssh-add

ssh-agent and ssh-add don't do what you want if run from terminal or xterm.

The excellent application sshLogin carries a GPL licence. This provides ssh-agent ssh-add functionality integrated with Apple's X11. You can even, in effect, install your ssh identity in your Apple keychain.

To install sshLogin:

You have to set up a keychain pair using ssh-keygen before using sshLogin.

2004-04-21

Setting environment variables

There is a special environment file which loginwindow reads each time a user logs in. The environment file is: ~/.MacOSX/environment.plist

Dot files aren't, by default, visible in the finder, so type cd; open .MacOSX in a terminal. If the environment.plist file is there you can open it in the Property List editor with a doubleClick. Otherwise, you will have to create the .MacOSX directory yourself.

To create the directory and file
$ cd
$ mkdir .MacOSX
$ echo "" > .MacOSX/environment.plist
$ open .MacOSX/environment.plist

This should open your new, empty environment.plist file in the Property List Editor. Select Root and Add a Child: the Key should be the name of the variable you want to set; Type should be String; Value should be the value you want to set for this variable. Next time you log in the variables should be set.

Environment variables set in environment.plist also appear in the standard bash environment. You can see all your environment variables using the shell command env from a Terminal window.

REFERENCE: http://developer.apple.com/qa/qa2001/qa1067.html

WARNING: do not set the DISPLAY variable—see my post re. X11 on Leopard.

2004-04-12

No xauth data

The common
Warning: No xauth data; using fake authentication data for X11 forwarding.
appears to be harmless. However, it is annoying. It arises when you have no xauth data!

The command
xauth list
displays all your xauth data. If there is no entry for your local display — which looks something like
localhost/unix:0 MIT-MAGIC-COOKIE-1 026666083d4e480d3e77544949281b49
you can generate one using the command
xauth generate :0 .

This creates an authorization using the MIT-MAGIC-COOKIE-1 protocol. Clients that connect with this authorization will be untrusted.
The period "." is part of the command; "untrusted" is probably what you want.
However, for some operations you need to connect as a trusted client. In case of problems, try using the command
xauth generate :0 . trusted
see man xauth or the X11 Security Extension Specification.

2004-04-01

Printing to DICE printers

You have to be connected inside the DICE firewall (eg. by physical connection, informatics wireless, or ssh) to use the printers ...

On a DICE machine, use the Unix command printers -s to list the available printers, + information on models, printservers, and location. (See man printers for other options.)

Use the Printer Setup Utility (in /Applications/Utilities/ on the Mac) to add a new printer:

IP Printing
Printer type: LPD/LPR
Printer Address: printbp.inf.ed.ac.uk
Queue Name: lwa
Printer Model HP LaserJet 4050 Series

Printer Type
is LPD/LPR
Printer Address
is the address of the server
Queue Name
is the name of the printer
Printer Model
can be left as Generic. However, if you get it right you can access printer-specific options from the OSX print dialogs.

2004-02-02

EUCS VPN and wireless

To use the central 802.11 wireless network (available in,: Raeburn Room, Old College; Hodgson Room, Science & Engineering College Office; Concourse, Appleton Tower, inter alia) and the University VPN, register online with the University Computing Service (EUCS) .

You do not need to download the Cisco VPN client. Once registered, you can connect to the University VPN server, vpngate.net.ed.ac.uk using PPTP with the built-in VPN client (accessible via Internet Connect on MacOSX v10.3 (Panther)).

Once connected via the VPN you can use the staffmail SMTP server: staffmail.inf.ed.ac.uk