How to Fix DeckLink Video Inputs Not Working in OBS

Using Blackmagic Design’s DeckLink capture cards with OBS Studio can bring a high level of professionalism to your video production setup, especially when dealing with live streams or advanced video integration. However, users often encounter frustrating issues in which OBS Studio doesn’t recognize the DeckLink inputs correctly—or at all. If you’ve found yourself stuck with a black screen, missing audio, or erratic input recognition, this guide will walk you through how to fix DeckLink video input issues in OBS step-by-step and get your workflow running smoothly again.

TL;DR

If OBS is not detecting your DeckLink video input, start by ensuring the latest Blackmagic Desktop Video drivers are installed. Check OBS Studio’s video capture settings and ensure that the input format and resolution match your source. Confirm system and app permissions, especially on macOS. If problems continue, consult DeckLink’s official software, test the card separately, and reduce GPU load on your machine if necessary.

1. Install or Update Blackmagic Desktop Video Software

The very first step to resolving DeckLink detection issues is ensuring you have the correct—and most recent—software installed. DeckLink devices require Blackmagic Design’s proprietary drivers and control panel, bundled together as the Desktop Video package. OBS relies on these components to detect and interpret the video feed.

Steps:

• Visit the official Blackmagic Design Support Page.
• Download and install the latest version of Desktop Video for your operating system.
• Restart your computer after installation for changes to take effect.

Important Tip: Make sure to uninstall any previous versions before updating as leftover files may lead to conflicts.

2. Check Input Format and Resolution Settings

DeckLink cards are notoriously sensitive to mismatched video formats and resolutions. If OBS doesn’t receive a signal, very often the culprit is a resolution mismatch between the DeckLink card and the input source (camera, switcher, etc.).

To properly set up the correct format:

1. Open OBS Studio and click the + icon under the “Sources” pane.
2. Select Blackmagic Device as a new video source.
3. In the device properties, choose your DeckLink card.
4. Manually set the input format to match your source (e.g., 1080p 59.94, 720p 50, etc.).
5. Toggle “Use custom audio device” if you expect audio from the same source.

To find out what formats your source supports, you can use Blackmagic Media Express or connect the device to a television or monitor that displays input specs.

3. Verify the Device in Blackmagic Media Express

Before pointing fingers at OBS, it’s wise to check whether the DeckLink card is working at all. Blackmagic provides the Media Express utility for precisely this reason. It’s also a handy way to test input sources and validate card functionality outside of OBS Studio.

How to test your DeckLink card:

• Launch Blackmagic Media Express from your desktop or applications folder.
• Select Log and Capture mode.
• If you see video or hear sound in Media Express, the card and inputs are functioning correctly.
• If not, try adjusting input settings or verify your source cables and connections.

If Media Express does not detect any signal, it’s likely a hardware or cable issue, not an OBS issue.

4. Grant Permissions and Check System Settings (macOS Specific)

For Mac users, especially those running macOS Catalina and above, system-level permissions can block OBS from accessing DeckLink devices. You’ll need to grant OBS permission to use screen capture and media devices in System Settings.

To fix this:

1. Open System Settings and go to Privacy & Security.
2. Under Camera, Microphone, and Screen Recording, ensure OBS is checked.
3. Reboot OBS after making changes to permissions.

In some cases, a full computer restart is necessary after granting these permissions.

5. Update OBS Studio

Older versions of OBS may contain bugs or lack certain device compatibility enhancements. OBS developers regularly update the software to support new drivers, SDKs, and hardware integrations, including Blackmagic DeckLink cards.

How to update OBS:

• Visit the official OBS Studio Download Page.
• Select your operating system and download the latest installer.
• Install over your current version to preserve your settings and scenes.

Note: Always keep a backup of your OBS settings before major updates, just in case changes or conflicts arise.

6. Set OBS Rendering Engine to DirectX or OpenGL

On some systems, the graphics rendering engine OBS uses (e.g., OpenGL vs D3D11/DirectX) may affect its ability to communicate properly with the DeckLink card. Try switching rendering methods to see if the issue resolves itself.

To switch rendering engines:

1. Go to Settings in OBS.
2. Navigate to the Advanced tab.
3. Under Video Rendering Engine, switch between DirectX and OpenGL (or vice versa).
4. Restart OBS and check if the video feed appears.

7. Reduce GPU Load

OBS, when run alongside other GPU-intensive applications, like video call clients or games, can struggle to process external capture inputs properly. If your DeckLink input is only partially functioning or seems to cut in and out, reducing GPU load could help.

Try these actions:

• Close unused applications, especially Chrome, Zoom, or video editing software.
• Set OBS to “High Performance” in your GPU control panel (NVIDIA Control Panel or AMD Radeon Settings).
• Lower OBS preview resolution via Settings > Video to reduce rendering stress.

8. Test with a Different Source or Port

Issues can also stem from your video source or port. Try testing a different HDMI or SDI input (depending on your DeckLink model) and also a different source like another camera or video switcher. Not all cameras output a “clean” video signal by default. Some require you to enable HDMI output manually in the camera menu.

Additionally, test other ports on the capture card. Many DeckLink units include multiple input options—one might fail while another works as expected. Don’t forget to verify cable quality and connector damage, especially with SDI, where connection integrity is critical.

9. Investigate Potential Conflicts with Other Capture Devices

If you have multiple capture devices connected—such as USB capture cards, Elgato devices, or webcams—OBS might prioritize or configure these differently, causing device clashes or configuration mismatches.

To simplify the device interface:

• Disable other video capture sources in OBS when testing your DeckLink card.
• Temporarily unplug other capture devices.

This is particularly helpful when diagnosing scene conflicts or automatic settings that OBS might apply incorrectly.

10. Reinstall OBS and Blackmagic Software (as Last Resort)

If nothing else works and your DeckLink card is confirmed to function (via Media Express or other software), a clean reinstall of OBS and Blackmagic software might root out any hidden corruption or compatibility errors.

To perform a complete clean uninstall:

1. Uninstall OBS and Desktop Video using your OS’s uninstaller or control panel.
2. Remove OBS configuration files (typically located in %appdata%\obs-studio on Windows or ~/Library/Application Support/obs-studio on macOS).
3. Reboot your machine.
4. Reinstall everything from scratch, testing the DeckLink input afterward.

Conclusion

Working with Blackmagic DeckLink cards and OBS Studio doesn’t have to be a technical nightmare