Update OBS Lower Thirds with Python and Text File

This article explains how to automate lower-third updates in OBS Studio by using a custom Python script to read data from a text file. By utilizing OBS Studio’s native Python scripting interface, you can dynamically update your stream overlays in real-time without manually editing text sources during a live broadcast. This step-by-step guide covers setting up Python in OBS, writing the automation script, and configuring your sources for a seamless live production workflow.

Step 1: Install and Link Python to OBS Studio

OBS Studio includes a scripting engine that supports Python, but you must have a compatible version of Python installed on your computer to use it.

1. Download Python: Install Python (typically version 3.10 or 3.11, depending on your OBS version’s compatibility) from the official Python website. Ensure you check the box to “Add Python to PATH” during installation.
2. Link Python in OBS: Open OBS Studio, go to Tools in the top menu, and select Scripts.
3. Set Path: Navigate to the Python Settings tab. Click Browse and select the folder where Python is installed on your system (e.g., C:/Users/YourUsername/AppData/Local/Programs/Python/Python310 on Windows).

Step 2: Create the Custom Python Script

Create a new Python file named obs_lower_thirds.py using a text editor or IDE, and paste the following code into it:

import obspython as obs

# Global variables to store user settings
source_name = ""
file_path = ""
update_interval = 2000  # Interval in milliseconds

def update_obs_text():
    """Reads the text file and updates the specified OBS source."""
    global source_name
    global file_path

    if not source_name or not file_path:
        return

    try:
        with open(file_path, "r", encoding="utf-8") as file:
            new_text = file.read().strip()
    except Exception as e:
        print(f"Error reading file: {e}")
        return

    # Locate the target OBS text source
    source = obs.obs_get_source_by_name(source_name)
    if source is not None:
        settings = obs.obs_data_create()
        obs.obs_data_set_string(settings, "text", new_text)
        obs.obs_source_update(source, settings)
        
        # Free up memory
        obs.obs_data_release(settings)
        obs.obs_source_release(source)

def script_properties():
    """Defines the user interface fields in OBS."""
    props = obs.obs_properties_create()
    obs.obs_properties_add_text(props, "source_name", "Target Text Source", obs.OBS_TEXT_DEFAULT)
    obs.obs_properties_add_path(props, "file_path", "Text File Path", obs.OBS_PATH_FILE, "*.txt", None)
    return props

def script_update(settings):
    """Triggers whenever settings are changed in OBS."""
    global source_name
    global file_path
    
    source_name = obs.obs_data_get_string(settings, "source_name")
    file_path = obs.obs_data_get_string(settings, "file_path")
    
    # Reset and start the timer
    obs.timer_remove(update_obs_text)
    if source_name and file_path:
        obs.timer_add(update_obs_text, update_interval)

Save the file. This script runs a background timer that reads your designated text file every two seconds and pushes any updated text to the designated OBS text source.

Step 3: Set Up Your Sources in OBS Studio

Before running the script, you must prepare the visual elements inside OBS Studio.

1. Add a Text Source: In the Sources dock, click the + icon and select Text (GDI+) for Windows or Text (FreeType 2) for macOS/Linux.
2. Name the Source: Name the source clearly, such as Lower_Third_Name.
3. Design the Graphic: Customize the font, size, color, and background of the text source to match your stream’s aesthetic. Place it in the lower-third region of your canvas.
4. Create the Live Text File: Create a blank text file on your computer named live_data.txt.

Step 4: Load and Configure the Script in OBS

With your text source and script ready, you can now link them together.

1. Open OBS Studio and go to Tools > Scripts.
2. Under the Scripts tab, click the + button at the bottom left.
3. Locate and select your obs_lower_thirds.py script.
4. Once loaded, script properties will appear on the right side of the window.
5. In the Target Text Source field, type the exact name of your OBS text source (e.g., Lower_Third_Name).
6. In the Text File Path field, click Browse and select your live_data.txt file.
7. Click Close.

Now, whenever you open live_data.txt, type a new name or title, and save the file, the text inside your OBS lower-third graphic will update automatically within two seconds.