Jitter correction really doesn't have anything to do with the length of the cable. Jitter can be caused by different things, but mostly it is cause by poor clocks or translating audio data back and forth between different digital transmission clock rates. A good example of this is transmitting S/PDIF over HDMI signal data. Jitter can also be caused by a "store-and-forward" mechanism of transferring digital data between data bus sections.
The minimum length of cable recommended is generally 1.5M (which is just over 4 1/2 feet). I always go 6 feet / 2 meter just to be safe. A short cable can cause reflections. This happens when the square wave pulse generated at the source hits the target receiver, but the pulse is actually reflected or echoed back down the wire to the source transmitter - which then can cause interference with the next generated pulses (sometimes cancelling out the pulses enough so that it comes across as a NULL pulse).
This doesn't just relate to digital SPDIF coax. The cable length / reflection issue occurs with all digital cables, including USB and HDMI as well.
There are times where you have a very strong transmitter (such as an HDMI transmitter chip). I have seen cases where equipment manufacturers actually recommend long HDMI cables. Sometimes short cables just won't work because of the reflection problems. Lumagen Radiance video processors is a good example here.
