TechnicalDifficulties is the sample code for the blog post Getting To Grips With The Core Media IO Camera Extension, a 3 part series, part 2 of 3: Creating an useful software Core Media Camera Extension, interprocess communication, and painless debugging, from The Offcuts.
You can also check out the sample code for part 1, and the sample code for part 3. They are all iterations of the same CMIO Camera Extension, with an increasing featureset.