What kind of video camera do you use?

I record videos in the car using a Casio EXS770 Exilim digital camera. Yeah...really :)

It's a simple, mid-range, pocketable, point-and-shoot 7MP camera with digital image stabilization (very important as described below) that can be had for less than $200. The video recordings I get are VGA (640x480) at 30 frames per second. I use a suction mount in my car.

The standard battery and an 8GB card (available under $50) is plenty to record all the day's sessions. For track videos, the Casio EXS770 Exilim records pretty consistently at 29MB of data per minute. For reference, that's 580MB in 20 minutes or 726MB in 25 minutes.

The recordings are stored on the SD card as .avi files and they're encoded with Microsoft ISO MPEG-4 video V1.1 (aka M4S2) codec (although I often convert them to other formats). It's not standard MPEG-4, so it's necessary to download a codec to your PC to play the raw footage. I use ffdshow and libavcodec...you can grab that from http://www.free-codecs.com/download/FFDShow.htm and I use Winamp to play the clips simply because I like the 5-second forward/backward skip hotkeys (left or right arrows). I'm not sure about Macs. Try this link.

The link from the camera to the PC is USB, so it'll take a few minutes per video to copy over. However, if you jump off the track and quickly want to show someone a video on your computer, just hook up the camera and open the video clip directly from the SD card (i.e. without copying it to your PC's hard drive). The USB connection is fast enough to play it back almost normally. One note is that there is no USB connector on the camera body. The USB cable plugs into a small dock (included) and the camera plugs into that. It's sorta stupid, but at least you don't have to plug in the power cable to the dock to transfer the files (of course you do if you want the camera to charge).

Back to the camera choice...it was deliberate. I originally bought a Sony Hi-Def video camera with a hard drive. What happens to a hard drive when you shake it? It shuts off. Bad solution for an in-car camera. I returned that for a Canon HV20 Hi-Def video camera which uses miniDV tapes. I paid a fortune for those cameras and was expecting top-of-the-line results. Tapes are sub-optimal because you don't have a great way to transfer the files to your PC (fine if you just use the camera as a player), but the real kicker was vibration (independent of the camera mount setup).

Every digital camera you can buy these days comes with some kind of image stabilization and all the reviews tell you to go for optical (vs digital) stabilization. My experience has taught me otherwise. Optical stabilization (aka "steady shot") detects the movement of the camera and counteracts that by physically moving the sensor or optics inside the camera (a little bit). This works great for most real-world applications, but when the camera's mounted to your car, you're dealing with large, high frequency vibrations that are significantly different from the (relatively) gentle swaying of your hands when you're recording Jimmy's recital.

So digital stabilization use a technique where there are some extra recording pixels on the sensor around the normal area where the image hits. Using digital signal processing, when the camera notices that from one frame to the next, part of Jimmy's violin moved off one side of the normal sensing area a little bit, it will (try to) capture that frame by recording those "extra" pixels off to the side (where the whole violin is still visible). When it puts all the frames together, it appears as though dad wasn't junked up on caffeine.

The key thing here is that when you physically move something, it has inertia and it takes real time to be repositioned. Then, before it gets into position, it needs to be somewhere else. The digital technique also requires real milliseconds to process, but it's negligible when recording at 30 frames per second.

At least this was my experience. Feel free to share yours.

..Kev