Pulling an audio file into a PHP script and auto-tuning it?

I wan开发者_StackOverflow社区t to write a PHP script that can programatically grab a .wav file from a URL, auto-tune it, and then either save it as a new file or output it using an "audio/x-wav" header, but I don't even know where to start. Are there audio manipulation libraries in PHP that can accomplish that?

1. file_get_contents or cURL or sockets for downloading
2. exec + ffmpeg for editing
3. header + readfile for sending to user