The HX-WA20 has a Digital image stabiliser which is better than most video cameras of this age and spec. Most big sensor size video cameras that were released more than two years ago have an Optical image stabiliser. Some compact cameras have digital Image stabilisation only, which simply boosts camera sensitivity (ISO) to obtain a faster shutter speeds to help prevent blur. No hardware is involved.
A Digital image stabiliser is actually the worst image stabiliser type amongst all big sensor size video cameras that have been on the market for a similar time to the HX-WA20.
An Optical image stabiliser is the best image stabiliser type amongst similar types of camcorder.