I'm a member of an accident reconstruction organization here in the southwest USA. If you know how many frames per second are on the video and have a video player which can go frame by frame, I can use landmarks to get your distance travelled per second (say 30 frames). I can go to the scene and measure the distance from the camera video.
I've done it in person. My calculation was within 1 mph of another GPS speed and it agreed with a Conservation of Linear Momentum reconstruction analysis, not to mention any data stored in an airbag ECU that can be downloaded.
My advice is, don't bother. You really aren't going to hide anything except from the casual observer. What I'm saying is, if you are involved in a fender-bender type crash, you can strip the data and probably no one at the insurance company or patrol cop will know the difference. However, if you are unfortunate enough to get involved in a fatal or serious injury crash that is analyzed by a competent reconstructionist, then there's very little that can be hidden.
Not to mention, a search warrant could be obtained to seize the raw data.
Just my opinion. Now go drive safely and don't worry about it.