This video on pet stain removal seems to be an internet go to that I have seen time and time again. In the video the host spreads baking powder on a cat vomit spot in the carpet and suggest to let it sit for some time. The spray the area with a 1:1 mixture of water and vinegar. The ensuing reaction will remove the vomit spot.
I call this solution for pet stain removal as the volcano approach to stain removal. Your using the same recipe for for carpet cleaning that you would for a science project volcano.
So the real question here is does this baking soda and vinegar reaction really help remove pet stains in carpet. The answer is yes the chemical reaction being produced is a rapid release of carbon dioxide gas. This is basically a fancy way of making carbonated water. The bubbles lift the soil solids to the surface where they can be removed with a towel.
As a professional carpet cleaner in Tampa FL I use this same reaction when cleaning carpets. I use a carbonated cleaning solution for pet stain removal and carpet cleaning.
You should know that pet stains can be difficult to remove and may require more than on application to remove the stain. If your still having difficulty removing this type of stain it might be time to call a professional.