Camera vibration mount.

Just tried to take a video today of my flight and used about 1" of
foam under the camera to hold it down. It does ok to absorb actual
frame vibrations but not the jiggles (potholes) on the taxiway and
other sudden shocks which send the camera rattling on the soft foam.
Any suggestions for material that will absorb the vibs but not too
rigid to send the camera shaking too much?