A small script that uses ffmpeg to convert mp4 video to mp3

ConvertMP4-MP3

$files = Get-ChildItem -Path . -Filter *.mp4

foreach($file in $files)
{
  $filename = $file.name
  $basename = $file.BaseName

  $command = "ffmpeg -i `"$filename`" -codec:a libmp3lame -q:a 0 `"$basename.mp3`""

  Write-Host $command

  Invoke-Expression $command
}