If any kind of mp2 to ac3 conversion is even possible, it would be export of audio track from a specific type of older MPEG videos. Your best option in such case is to use a video editor with legacy MPEG format support, which still is actually quite a number of software. Multimedia converters might also do the trick, but in case of video to audio conversions they often result in something you did not actually want.
Updated: August 7, 2023