How I learned to stop worrying and love the…
Colour Model Y′COCG


An in-depth discussion of the colour model Y′COCG. The advantage this colour model has over the widely used Y′CBCR is simpler – that means faster – computation, a stronger de-correlation of the colour planes, and dramatically reduced rounding errors. The very popular video codec H.264 is based on it, as well as the BBC’s own Dirac.

This is an advanced course: the attendees should be familiar with high-school maths, including functions, linear transformations and elementary 3 x 3 matrix operations.


Content includes:

  • A refresher on colour models and chroma subsampling;
  • Ladies and Gentlemen, His Majesty Y′COCG by Bill Shakespeare;
  • an ounce of codec programming;
  • in-depth H.264 – and Dirac at a glance.

Your Guidance

  • On Thursday 2nd of April 2015, from 14:00 to 17:00, at the Swiss Federal Institute of Technology in Écublens (a suburb of Lausanne, Switzerland).
  • The admission fee is CHF 50 for renting the equipped classroom, and an inscription is required, as the places are limited to 20 computer programmers, digital archivists and outlandish scholars.
  • All information gathered at this encounter could be used, without further notice, for our training courses, including A Course in Codec Programming.
  • In the morning an optional visit of our facility is organised.
  • And in the evening an optional dinner is organised in John Kerry’s favourite crêperie.


Having graduated in mathematics and computer science, Reto Kromer became involved in audio-visual conservation and restoration as early as 1986. From 1998 to 2003 he was head of preservation at the Swiss National Film Archive. Since 2004 he has been running his own preservation company, AV Preservation by He is currently a lecturer at the University of Lausanne, the Academy of Fine Arts Vienna and the Bern University of Applied Sciences, and on AMIA’s Board of Directors.