# How to automatically detect video start timestamp from in OpenCV

**URL:** https://forum.opencv.org/t/how-to-automatically-detect-video-start-timestamp-from-in-opencv/21099
**Category:** Python
**Created:** [May 27, 2025, 7:18am UTC](https://forum.opencv.org/t/how-to-automatically-detect-video-start-timestamp-from-in-opencv/21099 "2025-05-27T07:18:16Z")
**Posts on this page:** 1
**Page:** 1

<div class="post-metadata">

### Author: ![Zaid\_Siddiqui](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.opencv.org/zaid_siddiqui/32/12541_2.png) [@Zaid\_Siddiqui](https://forum.opencv.org/u/Zaid_Siddiqui)
#### Post date: [May 27, 2025, 7:18am UTC](https://forum.opencv.org/t/how-to-automatically-detect-video-start-timestamp-from-in-opencv/21099/1 "2025-05-27T07:18:16Z")

</div>

Hi everyone, in the below given code I want to automate the video\_start\_time to capture the start time directly from the first frame of the video and I am unable to do it.

import cv2  
import os  
from datetime import datetime

def hms\_to\_seconds(hms):  
“”“Convert hh:mm:ss string to seconds.”“”  
h, m, s = map(int, hms.split(“:”))  
return h \* 3600 + m \* 60 + s

def calculate\_offset\_seconds(start\_time, program\_time):  
“”“Return the number of seconds between program\_time and start\_time.”“”  
fmt = “%H:%M:%S”  
t1 = datetime.strptime(start\_time, fmt)  
t2 = datetime.strptime(program\_time, fmt)  
delta = (t2 - t1).total\_seconds()  
return int(delta)

def capture\_screenshots(video\_path, program\_timestamps, video\_start\_time, output\_dir=“screenshots”):  
“”"  
Capture screenshots from a video at program timestamps.

```
:param video_path: Path to the .mp4 file
:param program_timestamps: List of program times (e.g., ["19:01:30"])
:param video_start_time: The actual start time of the video (e.g., "19:00:01")
:param output_dir: Folder to save screenshots
"""
if not os.path.exists(output_dir):
    os.makedirs(output_dir)

cap = cv2.VideoCapture(video_path)
if not cap.isOpened():
    print(" Error opening video file.")
    return

fps = cap.get(cv2.CAP_PROP_FPS)

for i, prog_time in enumerate(program_timestamps):
    seconds_offset = calculate_offset_seconds(video_start_time, prog_time)
    frame_number = int(fps * seconds_offset)
    cap.set(cv2.CAP_PROP_POS_FRAMES, frame_number)

    success, frame = cap.read()
    if success:
        filename = os.path.join(output_dir, f"screenshot_{i+1}_{prog_time.replace(':', '-')}.png")
        cv2.imwrite(filename, frame)
        print(f" Saved: {filename}")
    else:
        print(f" Failed to capture frame at program time {prog_time}.")

cap.release()

```

if **name** == “ **main** ”:  
video\_file = “1010013\_2024-07-22\_19-00-01.Mp4”

```
# Real broadcast start time of the video
video_start_time = "19:00:00" # Match this with the actual time the program started

# These are timestamps shown during the broadcast on screen
program_timestamps = [
    # "19:04:32",
    # "19:05:00",
    # "19:26:16",
    # "19:28:06",
    # "19:29:16",
]

capture_screenshots(video_file, program_timestamps, video_start_time)

```