Is there software to automatically change song speed without transposing it

Question

Goal: automatically adjusting speed (bpm) of a given set of MP3 files in order to have a collection of music optimized to be heard when I am running. (I realized that I prefer to run with about 168 bpm in my ears).

Of course, I could have some software to detect BPM and then calculate and stretch/squeeze each song using Audacity or a similar tool, however, I'd prefer a solution which requires less manual operation.

Answer 1

I think soundstretch has the requirements. Command line based, it adjustes the song to the desired BPM. Try it because sometimes it estimates the wrong number of beats (rarely, it seems)

• Someone who has a wiki about the topic
• Official soundstretch webpage

Answer 2

Try Mixxx.

http://mixxx.org/features.php

Answer 3

I use Audacity. It's free, open-source, and can load and save mp3 or almost anything directly. Use the Change Tempo effect.