what is this film/ dots on my cider?

[Zwegert]

I reracked my cider for the first time and after a month this Film just started to form on the top with some white spots in addition (the dark spots on the picture are from my broken camera).
What should I do with this?
Label it off and just bottle it as planned? Tasted some out the bottom valve, no off flavors but tasted different from before the reracking, more tart but not sour. Could it be starting to turn into vinegar?
Thanks in advance.

 

[JohnSand]

Welcome aboard!
I've only made cider once. I bottled after the initial ferment, and didn't have spots on it. One portion I fermented naturally, with only the yeast already present in the cider. That part was much more tart than the others. I suspect lactobacillus.