Mp3 player that can slow down/speed up songs?

Question

Hi there!
Is there an mp3 player that allows me to change the speed of the songs? I know that audacity can do this, but I need an on-the-fly solution, I don't want to alter the files on disk.
Any suggestions will be appreciated!
Best wishes,
Rufus

Answer 1

From the mplayer2 manpage
scaletempo[=option1:option2:...]
              Scales audio tempo without altering pitch, optionally synced to playback speed (default).
                 speed=<tempo|pitch|both|none>
                      Set response to speed change.
                         tempo
                              Scale tempo in sync with speed (default).
                         pitch
                              Reverses effect of filter.  Scales pitch without altering tempo.   Add  '[  speed_mult
                              0.9438743126816935' and '] speed_mult 1.059463094352953' to your input.conf to step by
                              musical semi-tones.  WARNING: Loses sync with video.
                         both Scale both tempo and pitch.
                         none Ignore speed changes.
If you scale tempo
mplayer -af scaletempo=speed=tempo
(it has the same effect as the example in my previous post)
the pitch remains constant, but the song plays faster / slower.
If you scale pitch
mplayer -af scaletempo=speed=pitch
the song will play at the same speed (will have the same duration) but you can change the pitch.