Playback Flicker

Hello,

I have a 2014 Mac Mini that is solely for media playback on the TV. About a week ago the display would flicker while watching movies on iTunes. The content is only downloaded from iTunes and I have watched them before with no flicker so don't know why it would start doing it now.

When I say flicker, I mean that the image jumps and shows a ghost image of the currently playing movie but offset. It does not happen regularly but does happen at odd times and can be frequent. It does not seem to matter if the movie has fast-changing scenes or static.

I have the latest version of iTunes installed, it happened both before and after installing El Capitan upgrade with no improvement.

I only have one non-Apple program on the computer and that is Kodi for playback of MKV files. The playback/display does not flicker when watching videos on Kodi.

The iTunes content is on an external drive and the content for Kodi is on a separate external drive.

It's got me beat but would appreciate hearing from anyone with a similar problem or a solution.

Thanks