Andoir TV MP4 Playback Not Compatible?

[KodiUser1138]

Haven't seen anything about this and it seems really odd but I have an Andoid TV box Telus) playing back a movie in MP4 container and JF is doing live transcoding stating the container is not compatible while the containted streams are. This seems very strange to me as I though MP4 from super standard use. First time I've ever seen this action but not often I'm running this TV with a MP4 while also sitting next to my serer machine. Just wondering if there's some other hiccup or if that's just how it is?

[Generator]

Does the client supports the codec?
https://jellyfin.org/docs/general/clients/codec-support

And what is transcoding, the audio or video?

[KodiUser1138]

To my knowledge the client has no issues with the codecs. Neither was being transcoded. The info on the stream in the dashboard said the container (.mp4) was not compatible. Which seemed very odd to me. It was just H.264 and AAC 2.0 contained within. Never seen MP4 being an issue itself before.

[Aloviely]

Does the client supports the codec?
https://jellyfin.org/docs/general/clients/codec-support

And what is transcoding, the audio or video?

How about the autio, please?