Saving file path in a variable using tkinter

You could declare file_path as global variable in get_file_path

def get_file_path():
    global file_path
    # Open and return file path
    file_path= filedialog.askopenfilename(title = "Select A File", filetypes = (("mov files", "*.png"), ("mp4", "*.mp4"), ("wmv", "*.wmv"), ("avi", "*.avi")))
    l1 = Label(window, text = "File path: " + file_path).pack()

Then you can access that variable from anywhere in the script

------Edit------ According to what you said in your comment, i say you could use tkinter.StringVar to save the file path, and then to access it later when calling count_frames as an argument.

It could be implemented as the following:

from tkinter import *
from tkinter import filedialog

file_path_var = StringVar()

def get_file_path():
    # Open and return file path
    file_path= filedialog.askopenfilename(title = "Select A File", filetypes = (("mov files", "*.png"), ("mp4", "*.mp4"), ("wmv", "*.wmv"), ("avi", "*.avi")))
    file_path_var.set(file_path) #setting the variable to the value from file path
    #Now the file_path can be acessed from inside the function and outside
    file_path_var.get() # will return the value stored in file_path_var
    l1 = Label(window, text = "File path: " + file_path).pack()

window = Tk()
# Creating a button to search the file
b1 = Button(window, text = "Open File", command = get_file_path).pack()
# will also return the value saved in file_path_var
file_path_var.get()
window.mainloop()
print(file_path)

So now where ever your count_frames function is, as long as you have selcted a file first you should be able to just do

count_frames(file_path_var.get())