Transcoding behavior shouldn’t have changed significantly: that is, if playback quality is set to original and the media is compatible, Plex should stream it as-is (no transcoding). If the media isn’t compatible (e.g. bitrate exceeding capacity, unsupported codec for the client), Plex will attempt to transcode in order to produce a compatible version.
Plex have announced they’re going to re-add support for those library types, though there’s no ETA.
There’s two standalone apps focusing on those media types. I don’t have personal experience with the Plex Photos app, but I can absolutely and wholeheartedly recommend to give Plexamp a try — it should give you a much better experience for music.
