opencv trackbar

import cv2
from tkinter import *
import multiprocessing as mltp
from PIL import ImageTk, Image

win = Tk()
win.geometry("800x600")
win.configure(bg="gray17")
cap = cv2.VideoCapture('D:\Images_for_py\Videos/highway.mp4')
max_val = cap.get(cv2.CAP_PROP_FRAME_COUNT)
var = DoubleVar()

class Control():
    def __init__(self):
        self.scale = Scale(win, from_=0, to=max_val - 1, orient=HORIZONTAL,
                           variable=var,bg="gray17",fg="white", activebackground='#339999')

        self.scale.set(0)
        self.scale.place(x=100, y=455, width=604)
        self.label = Label(win)
        self.counter = 0
        self.key = True
        # self.display()
        mltp.Process(target=self.display())
        self.scale.bind("<ButtonPress-1>", lambda e: self.active_scaler())
        self.scale.bind("<ButtonRelease-1>", lambda e: self.active_auto())

    def to_pil(self, img):
        img = cv2.resize(img, (600, 400))
        img = cv2.cvtColor(img, cv2.COLOR_BGRA2RGB)
        image = Image.fromarray(img)
        pic = ImageTk.PhotoImage(image)
        self.label.configure(image=pic)
        self.label.image = pic
        self.label.place(x=100, y=50)
        cv2.destroyAllWindows()

    def active_auto(self):
        self.key = True

    def active_scaler(self):
        self.key = False

    def display(self):
        if self.key == True:
            self.counter += 1
            if self.counter >= max_val:
                self.counter = max_val
                cap.set(cv2.CAP_PROP_POS_FRAMES, self.counter - 1)
            self.scale.set(self.counter)
        else:
            val = self.scale.get()
            self.counter = val
            cap.set(cv2.CAP_PROP_POS_FRAMES, self.counter)

        _, frame = cap.read()
        self.to_pil(frame)
        win.after(20, self.display)


if __name__ == '__main__':
    Control()
    win.mainloop()

cap.release()