I tried to find information in the documentation of Rosegarden but I have not found anything about it (probably because of my bad English).

I would like to know if Rosegarden can change the tempo of an audio clip without changing the pitch.

I have to analyze a song and translate it into MIDI commands, however, the song does not match any standard "tempo", I'd like to be able to match it to a specific "tempo".

The best thing would be able to do everything within Rosegarden but if this is not possible and you have other tips are welcome.