If you are going to use the Popen subprocess method as I did you will have to remove p.wait() because it will wait for the video to end before running anymore code (it's putting the processes in a queue instead of threading them).
With the help from martineau and the answer he provided I used the following (after installing the pywin32 for python 3.5):
import pywintypes
import win32gui
displays = [[-10,0,980,530],
[954,0,980,530],
[-10,515,980,530],
[954,515,980,530]] #these are the x1,y1,x2,y2 to corner all 4 videos on my res (1920x1080)
def enumHandler(hwnd, lParam):
if win32gui.IsWindowVisible(hwnd):
print(win32gui.GetWindowText(hwnd)) #this will print all the processes title
if name in win32gui.GetWindowText(hwnd): #it checks if the process I'm looking for is running
win32gui.MoveWindow(hwnd,i0,i1,i2,i3,True) #resizes and moves the process
win32gui.EnumWindows(enumHandler, None) #this is how to run enumHandler
The x1,y1,x2,y2 might be different for your processes but these work just fine for vlc media player. I hope I was clear enough but if you don't get it done you should definitely check the answer provided by martineau.