How to stream music with (any) client

Hi,
I intent to stream my locally stored music (mp3 + ogg) with my mobile device.
In order to limit the download contingent I assume I need to transcode the stream somehow.

In the bottom line I want to have something similar to Spotify with locally stored music.

Can this be realized with Emby Media Server?

THX

Ok.
Does this mean if I stream a song that is locally stored as a mp3 file with size 4MB, I have to transfer 4MB data?
(With Spotify, depending on the settings, I transfer much less data per song.)