Controller

import keyboard
import time

if __name__ == '__main__':
  frames = [0]

  def forward():
    global last_frame_index
    while True:
      if not is_paused:
        last_frame = frames[-1]
        new_frame = last_frame + 1
        frames.append(new_frame)
        last_frame_index = len(frames) - 1
        print('Forward\t[%d]' % new_frame)
        time.sleep(0.01)

  def resume(*args):
    global hook
    keyboard.unhook(hook)
    hook = keyboard.on_press_key('k', pause)

    global is_paused
    is_paused = False

  def pause(*args):
    global hook
    keyboard.unhook(hook)
    hook = keyboard.on_press_key('k', resume)

    global is_paused
    is_paused = True

  def rewind(*args):
    global last_frame_index
    last_frame_index += -1
    try:
      print('Rewind\t[%d]' % frames[last_frame_index])
    except IndexError:
      last_frame_index = 0
    pause()

  def fastforward(*args):
    global last_frame_index
    last_frame_index += 1
    try:
      print('FastForward\t[%d]' % frames[last_frame_index])
    except IndexError:
      last_frame_index = len(frames)
    pause()

  global hook
  hook = keyboard.on_press_key('k', pause)
  keyboard.on_press_key('j', rewind)
  keyboard.on_press_key('l', fastforward)

  is_paused = False

  forward()