Personally i use FFmpeg that also comes with FFplay...
I use it in my own AutoIt script to covert music videos to mp3 with the help of the Lame encoder.
The AutoIt Script...
Code:
$ffmpeg = @TempDir & "\ffmpeg.exe"
$lame = @TempDir & "\lame.exe"
FileInstall(".\ffmpeg.exe", $ffmpeg)
FileInstall(".\lame.exe", $lame)
$input = FileOpenDialog("Open video file", @WorkingDir, "Video files (*.avi;*.mp4;*.flv)", 3)
$wavname = @TempDir & "\vidtomp3wav.wav"
$output = StringTrimRight($input, 3) & "mp3"
FileDelete($wavname)
;... Convert to WAV
$cmd = $ffmpeg & " -i """ & $input & """ -vn -f wav """ & $wavname & """"
$process = Run($cmd)
ProcessWaitClose($process)
;... Convert to MP3
$cmd = $lame & " """ & $wavname & """ """ & $output & """"
$process = Run($cmd)
ProcessWaitClose($process)
FileDelete($wavname)
FileDelete($ffmpeg)
FileDelete($lame)