File formats in Infuse Free

I’m a bit confused about exactly which file formats that’s supported in the free edition of Infuse on ATV4.

On the information frontage about Infuse it says:
“Play more, convert less
Go beyond iTunes and play most any media format including as MKV, AVI, MP4, WMV & many others”.

So as I understand it, MKV is supported by the free app?
The problem is, that I have a couple of MKV files, where Infuse tells me to sign up for the Pro version to get Infuse to support it.
All my MP4 and M4V files runs like a charm.

although mkv video is OK in the free version, you need the Pro version if it has certain Audio codecs (such as Dolby DTS) for which a license fee has to paid by FireCore to include support. This is quite frequent in films, less so in TV episodes.

Ahh… That makes sence! Its about the sound. Do anybody know if that can be changed in MakeMKV?