how to crop blackbars mpv ubuntu

Daniel Parker

3 min read

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07-02-2025

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Many videos, especially those from older sources or those formatted for widescreen TVs, contain black bars at the top and bottom (or sides). These black bars, also known as letterboxing or pillarboxing, can be distracting. This guide will show you how to easily crop these black bars from your videos using the powerful MPV media player on Ubuntu.

Understanding MPV and its Configuration

MPV is a highly versatile and customizable media player. Its flexibility comes from its command-line interface and configuration file. We'll be using the configuration file to automatically crop black bars. This eliminates the need to manually adjust settings for each video.

Method 1: Auto-Cropping Black Bars with MPV's Built-in Functionality

MPV offers a built-in feature to automatically detect and crop black bars. This is the simplest method and often works perfectly. The key is to use the --vf=crop=detect command-line option.

Step 1: Open the Terminal

Open a terminal window in your Ubuntu system. You can usually do this by pressing Ctrl+Alt+T.

Step 2: Use the mpv Command with the --vf=crop=detect Option

Navigate to the directory containing your video file using the cd command. Then, use the following command to play the video:

mpv --vf=crop=detect "your_video.mp4" 

Replace "your_video.mp4" with the actual path to your video file. MPV will now automatically detect and crop the black bars.

Step 3: (Optional) Saving the Cropped Video

This method only crops the video during playback. To permanently save the cropped version, you'll need to use a video editing tool like ffmpeg.

ffmpeg -i "your_video.mp4" -vf "crop=detect" "cropped_video.mp4"

This command uses ffmpeg to process your video and save a new, cropped version.

Method 2: Manual Cropping with MPV's Configuration File

For more precise control or for applying the same cropping settings to all your videos, you can edit MPV's configuration file.

Step 1: Locate the MPV Configuration File

MPV's configuration file is typically located at ~/.config/mpv/mpv.conf. If this file doesn't exist, create it.

Step 2: Add Cropping Options to mpv.conf

Add the following lines to your mpv.conf file, adjusting the width and height values as needed. These values define the cropped output resolution. You'll need to experiment to find the best values for your videos. You may also need to adjust the x and y values, which specify the top-left corner of the cropped area.

vf=crop=x=0:y=0:width=1280:height=720

Save the file. Now, when you play any video with MPV, it will apply these cropping settings. This will automatically crop all videos to the specified resolution. You may need to restart MPV for the changes to take effect.

Note: This manual approach requires some trial and error to find optimal values. The --vf=crop=detect method is generally recommended for its ease of use.

Method 3: Using a GUI Video Editor (External Solution)

If you prefer a more visual approach, you can use a GUI video editor like Kdenlive, OpenShot, or DaVinci Resolve. These editors allow you to manually select the area to keep and remove black bars with a visual preview. This is a more time-consuming method but provides maximum control.

Troubleshooting

• Incorrect Detection: If the automatic detection fails, try the manual method and experiment with different width, height, x, and y values in the mpv.conf file.
• No Change: Ensure you've saved the mpv.conf file and restarted MPV after making changes.
• Performance Issues: Cropping can be computationally intensive. If you experience performance problems, try reducing the cropping resolution.

By following these methods, you can effectively remove black bars from your videos using MPV on Ubuntu, improving your viewing experience. Remember to choose the method best suited to your needs and comfort level.