I have a very short mp3 file that I've uploaded, but it is currently over 200k and it really needs to be less than 50k as it is only 6 seconds long. I figure it is probably in 256kbps format. How can I convert it to 32kbps or 64kbps using Publitio? I can do it in my normal audio editor, but wondered if I could save me having to do that.