A Sony Hi-8 camcorder overlooking the site is connected to a VideoPix board in a Sun SPARCstation (which can select between 2 composite inputs and one S-video input). At regular intervals (currently 1 hour) a program "vfc2ppm" is run to grab a frame and generate a PPM image, which is converted to JPEG using ImageMagick "convert", and stored in the archive. Images are captured at closer intervals (currently 5 minutes) and saved as the "current view". The hardware and conversion software is not sufficiently fast to permit regular use of a live shot, especially by many users. The conversion logs for the 5-minute images and the hourly images are available.
The MPEG animation is created using "mpeg2encode" from PPM images saved every 5 minutes. Since there is little action during the night, not all the frames are used. The animation starts at about 07:24 in the morning.
The current image is available at two URLs; on the main TRIUMF server and on the Electronics Shop server (which is the machine with the frame grabber).
On the second server (running Apache), the image is served with an Expires header, ensuring that hierarchical cache servers can cache the image for the correct amount of time, and also that users will see a recent image automatically without reloading the page. (There is no refresh tag, but leaving the page and returning or confirming the Location box are sufficient to obtain an update.)
TRIUMF users with an account on Alph04 may execute the script /web1/advax/photo-loop.sh, which uses xv to load the X-terminal background with the current image every 5 minutes. Archive Index
A.Daviel
