Android app to re-encode audio in video files?

I have just started getting into Google Chromecast and have, sadly, discovered that many of my video files won’t cast with sound. I’ve since learned it’s because Chromecast does not support AC3 or DTS audio.

So I need an app that can re-encode audio WITHOUT re-encoding video as well, since the video plays fine in Chromecast, just without sound.

I don’t have access to a windows machine right now, so I need an app that I can run on my android tablet.

Is there an app that can do this? Free or paid, doesn’t matter.

Thanks in advance for your help!