audacity "change speed" type operation with mencoder/ffmpeg?
I would like to resample and reencode some mp3 files so that they play at a slower speed (at around 90% of the original speed), and I want the pitch to change correspondingly, i.e. i *don't want* any sort of pitch compensation to be performed. Basically my goal is just to "fix" these mp3 files that seem to be speeded up versions of a speech recording (and the speaker's voice sounds higher than it actually is) so I just want to reverse the effect.
Audacity, which I use at home with Windows, has this feature. I want to do the same thing at work (we use Ubuntu Linux, and both ffmpeg and mencoder are available).
How can I achieve this with either of these programs? Can anyone give me a sample command?
Thank you in advance.