How to Change Default Subtitle Font and Size in mpv?

The mpv media player is highly customizable, but because it lacks a traditional graphical user interface for settings, changing the default subtitle font and size requires editing its configuration file. By creating or modifying a text file named mpv.conf, you can define your preferred font name and size using specific configuration lines. This article provides a quick, step-by-step guide on how to locate your configuration folder, create the necessary file, and apply the correct commands to permanently customize your subtitle appearance.

Step 1: Locate or Create the mpv.conf File

To change the default settings, you need to add configuration lines to a file named mpv.conf. The location of this file depends on your operating system:

• Windows: C:\Users\<YourUsername>\AppData\Roaming\mpv\ or inside the same folder where your mpv.exe is located (often called a portable configuration).
• macOS and Linux: ~/.config/mpv/

If the mpv.conf file does not exist in that directory, simply create a new, blank text file and name it mpv.conf (make sure the extension is .conf and not .conf.txt).

Step 2: Add Font and Size Syntax

Open the mpv.conf file in any plain text editor (like Notepad, TextEdit, or Vim) and add the following lines to customize your subtitles:

# Specify the font name (case-sensitive)
sub-font="Arial"

# Specify the font size (default is usually around 55)
sub-font-size=45

Replace "Arial" with the exact name of any font installed on your system (e.g., "Trebuchet MS", "Helvetica", or "Noto Sans"). Adjust the sub-font-size number up or down to match your viewing preferences.

Step 3: Advanced Subtitle Customization (Optional)

If you want to enhance readability further, you can also adjust the subtitle background, borders, and colors by adding these optional lines to your mpv.conf file:

# Change text color (Hex format: Blue-Green-Red)
sub-color="#FFFFFFFF"

# Add a black border around the text
sub-border-size=3
sub-border-color="#FF000000"

# Alternatively, add a translucent background box
sub-shadow-offset=1
sub-shadow-color="#33000000"

Step 4: Save and Test

Save the changes to your mpv.conf file and close the text editor. Open a video file with mpv to test your new layout. If the subtitles do not change, double-check that the font name is spelled correctly and that the mpv.conf file is placed in the correct directory.