#!/bin/bash



for /R .\test %%F in (*.avi) do 

    mencoder "%%~fF" -o "%%~dpF%%~nF_conv.mp4" -oac copy -ovc lavc -lavcopts vcodec=mpeg1video -of mpeg

    if exist "%%~dpF%%~nF_conv.mp4" (

        del "%%~fF"

        ren "%%~dpF%%~nF_conv.mp4" "%%~nxF"

    )

done