These pages explain the theory and technical details of Digital Video:
Slightly simpler coverage with some useful tables comparing what ends up on different format media.
Includes some nice graphics to illustrate the sampling process, active areas and interlacing
This has some nice graphical examples of what interlacing is about and explains the issues of “3:2 pulldown” needed to convert 24fps film to NTSC. Pulldown is less of an issue in the PAL world because they just play the 24fps movie at 25fps, with the lovely side-effect that the audio becomes out of pitch.
A good overview of the different ways you can move video from one piece of equipment to another
A number of filters by the author of DeShaker