There is a new restricted house (100 m2) that has fallen down 5 cm in 2 years.
I have drone videos of it in 2023.
I am doing to take new videos now.

How can you set the specific fly height?
How can you see from old videos what altitude the drone is flying.

You need to record the video captions (aka sub titles) to get that information from the flight.  

Hi,

Baro Height is set to zero at take-off.
So if you start at exactly at the same location and the same drone position you can compare heights.
Having said that ; 5 cm is within the height variations of the mini2, so no way you can valid the heights to draw a good conclusion

cheers
JJB