stretchplayer (audio player with time stretch and pitch shift)

StretchPlayer is an audio file player that allows you to change the
speed of the song without changing the pitch. It will also allow
you to transpose the song to another key (while also changing the
speed). This is a very powerful tool for musicians who are learning
to play a pre-recorded song. Its features include Time Stretch (25% to
125% of song speed, without changing pitch), Pitch Shift (up or down 1
octave), A/B repeat, and lots of keyboard accelerators.

The player supports all the audio formats that libsndfile supports,
which currently includes OGG/Vorbis, WAV, W64, AIFF, SND, and
FLAC. Note that neither libsndfile nor StretchPlayer supports MP3
files for patent liability reasons.

This package uses POSIX filesystem capabilities to execute with
elevated privileges (required for realtime audio processing). This
may be considered a security/stability risk. Please read
http://www.slackbuilds.org/caps/ for more information. To disable
capabilities, pass SETCAP=no to the script.