i put music on iPhoto when in renders no music is heard. But the video has sound.

I have 3.2 GHz Intel Core I5 with 8 GB 1600 MHz DDR3, I believe my iphoto and Itunes are updated , I burn and automatically export to itunes in 720 P (i guess it's faster in rendering it, in 2 hours worth render time is two days ). But the finish product does not have music.