video renders well on mac, but has bizarre effect on windows I have been editing a video which has rendered fine up until recently, I had it in a .mp4 format on a windows machine editing using wevideo, and I sent it to my friend who edited it on a mac, I think using aftereffects, and converted it to a .mov and now it has this strange effect, but only when I download it to the local machine (by the way the black bars are fine, what I am confused about are the horizontal lines):

before:


on my phone after:



on my computer after:



What could be going on and how should I fix it?

thanks!
Those horizontal lines you're seeing are what you would call Interlacing and it's usually done in an attempt to increase a video's frame rate without using more bandwidth (in other words, make it play smoother and take up less space).  You can easily get rid of this by running your video through a program like Handbrake and using their "Decomb" filter.

There are other, more advanced methods to clean this up as well.

I personally use Davinci Resolve and I've read that you can even do it in VLC Media Player, but I think handbrake is the quickest and easiest way to accomplish deinterlacing your video.