Det här kom jag inte ihåg hur det skulle göras.
Men jag gjorde en "test.mp3" med "ljudinspelare" och la den i "hemfoldern". (Dvs .../home/hans/..)
Det här blev resultatet.
..
hans@hans-ubuntu:~$ mplayer -af scaletempo test.mp3
MPlayer 1.0rc2-4.2.3 (C) 2000-2007 MPlayer Team
CPU: Intel(R) Pentium(R) 4 CPU 3.00GHz (Family: 15, Model: 4, Stepping: 3)
CPUflags: MMX: 1 MMX2: 1 3DNow: 0 3DNow2: 0 SSE: 1 SSE2: 1
Compiled with runtime CPU detection.
mplayer: could not connect to socket
mplayer: No such file or directory
Failed to open LIRC support. You will not be able to use your remote control.
Playing test.mp3.
Audio file file format detected.
==========================================================================
Forced audio codec: mad
Opening audio decoder: [libmad] libmad mpeg audio decoder
AUDIO: 44100 Hz, 2 ch, s16le, 128.0 kbit/9.07% (ratio: 16000->176400)
Selected audio codec: [mad] afm: libmad (libMAD MPEG layer 1-2-3)
==========================================================================
Couldn't find audio filter 'scaletempo'
[libaf] Couldn't create or open audio filter 'scaletempo'
Error at audio filter chain pre-init!
Exiting... (Fatal error)
hans@hans-ubuntu:~$