The VideoLAN Forums

VLC has to do nothing. AC3 decoding needs a license, and for that you need to pay.

A workaround is to convert the AC3 audio to AAC.
A description about this can be found here: http://ivanrf.com/en/convert-unsupporte ... rom-video/

I had the same issue and I solved it by modifying the audio codec to AAC. I use two other apps for this.
Here it is explained: http://ivanrf.com/en/convert-unsupporte ... rom-video/