Create video of a timer

timer.py

import cv2
import numpy as np
import math

fontScale = 10
margin = .2
fontThickness = 3
backColor = (0,0,0)
textColor = (255,255,255)
FPS = 59.94
startTime = -9
endTime = 61*60
font = cv2.FONT_HERSHEY_SIMPLEX
decimalPoints = 1
numFrames = math.floor((endTime-startTime)*FPS)
countKey = "b"

messages = []

def parseTime(s0):
    parts=s0.split(":")
    if len(parts)>2:
        return 3600*int(parts[0])+60*int(parts[1])+float(parts[2])
    elif len(parts)==2:
        return 60*int(parts[0])+float(parts[1])
    else:
        return float(parts[0])

with open("counts.txt") as f:
    for line in f:
        counters = line.strip().split(" ",2)
        if len(counters)>=2 and counters[1] == countKey:
            t = parseTime(counters[0])
            messages.append((t, counters[2] if len(counters)>=3 else ""))
            
def getMessage(t1):
    msg = ""
    for t,m in messages:
        if t <= t1:
            msg = m
    return msg
    
def getText(n):
    t = n / FPS + startTime
    sec = math.floor(t)
    frac = math.floor((t-sec) * 10**decimalPoints)
    if t<0:
        text = str(sec)
    else:
        text = "%02d:%02d" % (sec//60,sec%60)
        if decimalPoints:
            text += ".%0*d" % (decimalPoints, frac)
    msg = getMessage(t)
    return text,msg

def getSize(text):
    return cv2.getTextSize(text, font, fontScale, fontThickness)[0]

print("Getting dimensions")    
    
maxWidth = 0
maxHeight = 0  
prevText = None  
prevMsg = None
    
for n in range(numFrames):
    text,msg = getText(n)
    if text != prevText:
        size = getSize(text)
        maxWidth = max(maxWidth,size[0])
        maxHeight = max(maxHeight,size[1])
        prevText = text
    if msg != prevMsg:
        size = getSize(msg)
        maxWidth = max(maxWidth,size[0])
        maxHeight = max(maxHeight,size[1])
        prevMsg = msg

lineHeight = maxHeight
m = int(margin*lineHeight)
width = maxWidth + 2*m
height = 2*lineHeight + 3*m
line1Y = m+lineHeight
line2Y = 2*m+2*lineHeight
        
print("dimensions:",width,height)
    
out = cv2.VideoWriter('timer.mp4',cv2.VideoWriter_fourcc(*'mp4v'), FPS, (width,height))

print("Generating video")

prevText = None
prevMsg = None

for n in range(numFrames):
    text,msg = getText(n)
    if text != prevText or msg != prevMsg:
        print(text,msg)
        img = np.zeros((height,width,3),dtype=np.uint8)
        img[:] = tuple(reversed(backColor))
        size = getSize(text)
        cv2.putText(img, text, (int((width-size[0])/2),line1Y), font, fontScale, textColor, fontThickness, lineType = cv2.LINE_AA)
        size = getSize(msg)
        cv2.putText(img, msg, (int((width-size[0])/2),line2Y), font, fontScale, textColor, fontThickness, lineType = cv2.LINE_AA)
        prevText = text
        prevMsg = msg
    out.write(img)