convert.cmd

@echo off

ECHO =========================

setlocal enabledelayedexpansion

set argCount=0
for %%x in (%*) do (
   set /A argCount+=1
   set "argVec[!argCount!]=%%~x"
   set "argFex[!argCount!]=%%~nxx"
)

echo Number of files to process: %argCount%

for /L %%i in (1,1,%argCount%) do (
  echo Processfile !argVec[%%i]!
  cmd /k C:\ffmpeg.exe -i "!argVec[%%i]!"  -c:v copy -c:a libmp3lame "C:\convert\!argFex[%%i]!"
  echo File saved at C:\convert\!argFex[%%i]! 
)

explorer.exe C:\convert

ECHO =========================

PAUSE