MX Player is one of the most popular media players for Android, but many users encounter the frustrating "This audio format (AC3) is not supported" error. This happens because MX Player removed official support for AC3, EAC3, DTS, and TrueHD due to licensing restrictions. To fix this, you must download and install a . Step 1: Download the Correct Codec Pack MX Player Custom Codec 2.7.x