Daniel Lemire's blog

, 1 min read

Giving Efficient Distance Lectures on a Budget

As part of CS6905, I lecture from my basement near Montreal, to New Brunswick in Easter Canada. Sounds crazy? Well, according to my collaborators, this works well for everyone involved. We use webhuddle to broadcast the lectures. We are short of a video stream, but it seems that it is not a critical flaw.

If, like me, you prepare your slides using LaTeX, then you have a small problem because webhuddle expects either PowerPointish files or a zip file containing JPG or GIF images. Don’t go for JPG images as they are too big when your slides are mostly text and a flat background. Here’s a script to convert a PDF file into a bunch of GIF files (it can be improved upon):


pdftoppm $1 $1ppm
listoffiles=""
for i in $1ppm*.ppm
do
echo "converting file " $i
convert -resize 800x600 $i $i.gif
listoffiles=$i".gif "$listoffiles
echo "you can now delete "$i
done
echo "now zipping "$listoffiles
zip -9 $1.zip $listoffiles
echo "zip file is "$1.zip