[Milhouse]

Here is the screenshot of the window with "Add music".
http://imgur.com/PbzYemL

Thanks, I've been able to reproduce on the Pi1 and identified the first "bad" build, it's #0304.

My steps to reproduce:

1. "systemctl stop kodi"
   
2. "mv .kodi .kodi.bak"
   
3. "systemctl start kodi"
   
4. Wait for system to become idle (in top/bcmstat.sh, I wait for %iowait to be consistently zero) - idle CPU load should be about 9% on a "clean" 1GHz Pi1
   
5. Enter Music > Files (complete first run wizard if required)
   
6. In #0303, CPU load remains about 8-9% @1GHz, but in #0304 the CPU load is 45-50%
   

It's not obviously dirtyregions rendering - at least, nothing is shown when visualizedirtyregions is enabled - however there are a couple of dirty-region optimisations that are introduced in in #0304, which might explain the overhead.

There is absolutely nothing being written to the log (even with all logging components enabled) that would explain the additional processing so I'm not sure what the cause is... there are some add-on related changes in #0304, could this be the cause, searching for addons, maybe? (edit: audioencoder add-ons were changed in #0303 - looking at wrong post, d'oh)

Certainly, something unnecessary/excessive now seems to be occurring in Music, and might also explain recent reports of poor performance when playing music (as CPU cycles are being wasted on something other than playing music).