When I try to stream a movie either from NAS or from a movie addon on kodi It get laggy and spikey meaning. Sometimes it loads fine but then it lags and when I check the stats frame I see could error 25% and upto 2500% sometimes.
Is it because I use a mobile charger as supply for the rpi 3?
I would say yes, it’s the same on my Pi (also an Pi3) I use 50Hz shows to adopt the different framerates from videos best possible, another option is to change to adopt framerate from video. But I can’t say where to option is atm.
Yes. You were playing 25fpv video on a 60Hz display.
There “error” isn’t an error but a measure of how well the framerates are aligned.
You should always enable “adjust display refresh rate” if you care about smooth video.