Go this link and download a build package.
For the version, choose the newest release version number like 4.3.1.
For the Architecture, choose the Windows 64 bit.
For the Linking, choose the Static.
For the License, it’s doesn’t matter if you just use it on local.
After selected, just click Download Build. You will get a zip package.
Unzip the package to any location you want. I recommend to the C:\ffmpeg
After that, just add the bin folder to the System Environment PATH.
Open Windows PowerShell and input ffmpeg. If you get the right output, you can enjoy ffmpeg now.
refer link:
https://www.youtube.com/watch?v=qjtmgCb8NcE