high mp3 quality->low conversion using PHP

How to convert 320 kbps mp3 file into e.g. 32 kbps one usi开发者_如何学Pythonng PHP?

I suppose you could call some command-line MP3-related program that would do the conversion.
The result would probably be better than using a purely-php-based library¹.

For example, lame might be useful, here.

Then, from your PHP code, to run that external program, you'll nee to use one of the Program execution Functions, like exec().

^1. _{If there is even such a thing}