Abstract: For synchronising the operation of first and second video devices referenced by respective timecodes and operable at different video rates in response to first and second timing references where the first video rate is a m/n times the second video rate, a predetermined phase relationship is established between the first timecodes from the first video device and second reference signals for the second video device and then target timecodes for synchronising the second video device are derived from the first timecodes and the second reference signals. In a first embodiment second timing reference signals are generated with a fixed, repeatable phase relationship with respect to the first timecodes by resetting the timing of the second timing reference signals in response to a first timecode which, when divided by m, gives a predetermined remainder.