Welcome and Hello.
First, please head on over to the New Mystery Shoppers area of the forum and read, read, read the 12 or so topics that are "pinned to the top of the list."
Second, realize that certification is really not needed for 99.9% of shops. What counts is your track record in "newbie" shops. Then in more advanced shops as you prove yourself to be objective and reliable.
Third, please consider walking before you run. Do some non-video apartment, new home and auto purchase shops to get comfortable with each type before you add video to the mix. After all, do you really want your rookie mistakes to be recorded ??? And, yes, you will make rookie mistakes, like we all did.
Fourth, the forum has a really great "search" feature. Input a topic and then a time period (last month, last year, etc). You will find that different shoppers hold very strong, and often opposing, opinions about which is the BEST of anything, including video MSCs
Fifth, most people need some hands-on video training. AND, you will see little or nothing on the job boards of video MSCs until you have sent them an acceptable test video. ACCEPTABLE usually, but not always, means using a PV-500 recorder with a button cam that produces acceptable resolution and sound quality. (Please search "video" for "past year" to find such discussions.)
My personal favorite video MSCs include Clear Evaluations and The Shadow Agency. The folks at either can suggest the best equipment to consider, tell you the standards for acceptable sound and picture, and recommend reliable suppliers of equipment and training. If you want an MSC that will loan you video equipment to try out on their shops, go to Ellis aka EPM.
Video is NOT for everyone, so I always suggest loaner equipment for a few tries before buying.
Based in MD, near DC
Shopping from the Carolinas to New York
Have video cam; will travel
Poor customer service? Don't get mad; get video.