I remembered questions about waving flags from before because I was involved in an answer at that time.
If not actually recording a waving flag or spending lots of money on software, animating a gif I would say will do the job for you, - that is if you are making something that is not supposed to be broadcasted somewhere.
These days, it seems to be no end to what you can do online.
(sorry about the editing......)
Post from 2014
This message was edited 2 times. Last update was at Aug 05. 2017 05:36
Just something.
https://www.petitpoisvideo.com