Roku Black Screen and sound popping

[Spackler]

I just downloaded that one because the first time I ran the command in powershell I get the following error.

ffmpeg.exe : The term 'ffmpeg.exe' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the name, or if a path was included, verify that the path is correct and try again.