Audio file speed too fast

[Marco6]

Hi. I've already spent some time reading through the forum topics, but haven't found a solution to my problem.
I'm MAC format, trying to extract audio directly from a DVD using MacTheRipper.
I choose Title-Chapter extraction, my range of chapters, then click on the 'D' (Demux)
button, then on Streams to extract only the audio to AC3 format.
I then take that AC3 file into FFMpegX, select Audio file to mp3, select my preferred
bit rate in the audio section, then Convert.
I get an mp3 file, but when I play it in iTunes or in Audacity, the speed is increased.
Any suggections on what I am doing wrong or missing?
Thanks for any help.

[Case]

Try ripping with Title - chapter extraction to a non-demuxed single VOB file, then converting with ffmpegX Movie audio to mp3 preset. Perhaps the VOB style timing prevents the speed increase? Worth a try...