CentOS 6.4 and Audio Conversion

I'm having issues with setting up a Centos 6.4 server to convert audio tracks needed for a project I'm currently involved in.

So users of a site I've been working on can Upload tracks, but because some browsers don't support all audio types I've got to use a audio converter to convert mp3 -> ogg, and ogg -> mp3. (Would also like m4a support and maybe others).

On my local (Ubuntu) I've had no problem installing SoX and FFmpeg to do this. However when it comes to moving over to the Centos server I've been running into a number of problems. Installing SoX is fine, but it doesn't haven't Mp3 support, and the packages it needs for it (Sox-plugins-Freeworld + Sox-plugins-nonfree) are seemingly not supported by Centos 6.4 only by Fedora 19. Because it keeps throwing up the Glibc 2.14 needed, but I understand that Centos 6.4 only support glibc 2.12. Now I can install FFmpeg but now I need extra plugins for that to convert to Ogg, of which is again seemingly not supported by Centos 6.4. I tried pipe-lining the tracks between the pair to avoid the issues, but the bit-rates aren't converting properly and the resulting track skips and the audio quality is poor . I was thinking of converting tracks to WAV and then using either FFMpeg or SoX to convert them to ogg or mp3 but it's not a viable strategy since Wav's can be very large tracks. Plus converting loosely to looseless and back again can have issues again.

So my questions is, firstly can anyone confirm that both SoX and FFmpeg plugins aren't supported in Centos. Secondly is there a easy audio converter that can convert tracks without losing quality for Centos that I've clearly overlooked?

.