So I use Divx web player and after following a guide I made it play avi files with sound. After 2 seasons later (show not reality), the same avi files did not play sound anymore. I re checked my ac3 files in quicktime and regular library and they both are there. Persian is also installed. so no changes has been made.

Any ideas to what the problem could be?

Using latest version of Divx.

MBA 13" late 2013 (haswell)