I would like to take an mp3 file and re-encode it to play faster (perhaps at 1.5x speed). I primarily use avconv in debian linux, but can use any other program if recommended. I can use any operating system if linux isn't the preferred method.
I understand that VLC can play files at faster than normal speed, but I want to re-encode the files so that they can be played faster on devices that do not support VLC (such as my iphone).
Also: I am doing this for 50+ files, so an automated command-line interface would be preferable, if possible.
Any help is appreciated. And as always, thank you for your time.