timestamp not updating

[bowen73]

I've got a script running from startup on my raspberry pi using

import time

and

timestamp = time.strftime("%Y-%m-%d_%H:%M:%S")

but when I grab a video and timestamps the filename it uses the same timestamp over and over. If I run it manually it puts the correct timestamp, so I think it grabs it once when the script is started but not each time it needs to timestamp, if you get what I mean??

so basically, how can I have it grab the correct timestamp instead of just once when the script is run at startup?

this is my full code:

#!/usr/bin/python
# 360 rotation and video
from Adafruit_MotorHAT import Adafruit_MotorHAT, Adafruit_DCMotor, Adafruit_StepperMotor
import atexit
import RPi.GPIO as GPIO
from signal import pause
import picamera
import time
from time import sleep
from subprocess import call
import os

# Setup GPIO Pins
GPIO.setmode(GPIO.BCM)
GPIO.setup(18, GPIO.IN, pull_up_down=GPIO.PUD_UP)

#setup camera
camera = picamera.PiCamera()
#camera.framerate = 25
#camera.resolution = (1280, 720)

#Grab the current date & time
timestamp = time.strftime("%Y-%m-%d_%H:%M:%S")

# Setup Motor
# create a default object, no changes to I2C address or frequency
mh = Adafruit_MotorHAT(addr = 0x60)

# recommended for auto-disabling motors on shutdown!
def turnOffMotors():
        mh.getMotor(1).run(Adafruit_MotorHAT.RELEASE)
        mh.getMotor(2).run(Adafruit_MotorHAT.RELEASE)
        mh.getMotor(3).run(Adafruit_MotorHAT.RELEASE)
        mh.getMotor(4).run(Adafruit_MotorHAT.RELEASE)
 
atexit.register(turnOffMotors)

myStepper = mh.getStepper(200, 1)       # 200 steps/rev, motor port #1
myStepper.setSpeed(10)                  # 10 RPM

while True:
    input_state = GPIO.input(18)
# filename = os.path.join(destination, dt.datetime.now().strftime('TFF_%Y-%m-%d_%H.%M.%S.h264 -t 10000 -w 1296 -h 730 -fps 25 > /dev/null'))
    if input_state == False:
        print('Button Pressed')
        sleep(.5)
        print("Camera recording for 28 seconds")
    # Setup the camera
    #with picamera.PiCamera() as camera:
    # Start recording
        camera.start_recording("/home/pi/Videos/360Video.h264" )
        sleep(2)
        print("turning motor 1 revolution, approx 26 seconds")
        myStepper.step(200, Adafruit_MotorHAT.FORWARD, Adafruit_MotorHAT.MICROSTEP)
        print("motor stopped")
        sleep(2)
        # Stop recording
        camera.stop_recording()
        # The camera is now closed.
        print("Camera finished recording")
        sleep(.5)
        print("Converting the video to mp4.")
        # Define the command we want to execute.
        command = "MP4Box -add /home/pi/Videos/360Video.h264 /home/pi/Videos/360Video_transfer/"+timestamp+"_360Video.mp4"
        # Execute our command
        call([command], shell=True)
        # Video converted.
        print("Video converted.")
        sleep(.5)
        print("deleting h264 file")
        os.unlink("/home/pi/Videos/360Video.h264")
        sleep(.5)
        print("h264 file deleted")