How can I trim mp3 file? [duplicate]

Possible Duplicate:

Crop MP3 to first 30 seconds

I'm using this class http://www.phpclasses.org/package/5275-PHP-M开发者_StackOverflowanipulate-MP3-audio-files.html but I get an error, I want to create a website that sell a music online I would like to have a preview like about 15-20 seconds how to this ? Any help? Thank you.

Pekka is right. Also, check older questions - here you have a full answer: Crop MP3 to first 30 seconds It's not using the class you have but it will do the work great. I've used it few times in the past and it's the better way to do things with audio/video.