aac buffering. anything else i can do?

Hi. I have my lms on a raspberry pi b (512mb) and I'm trying to play an acc radio stream - boom and duet only so due to transcoding the buffering is really bad and looking at the pi data the FAAD conversion that is taking up 50-60% of the cpu and i guess this is the issue.

I've increased buffer to max 30 secs and also try various memory splits on the pi but just wondering if this is just a battle I'm going to lose or can i tweak anything else?

Any advice would be great.