Setlocal enabledelayedexpansion

mkdir Stripped
for %%f in ("*.mp4") do (ffmpeg -i "%%f" -map_metadata -1 -c:v copy -c:a copy -map 0:a -map 0:v "%%~nf-out.mp4")
move *out.mp4 Stripped

Set "Pattern=-out"
Set "Replace="
cd stripped
for %%f in ("*.mp4") do (

Set "File=%%f"
Ren "%%f" "!File:%Pattern%=%Replace%!"
)