Using a Capture Card as a Video Source in OBS Studio

The short answer

In OBS Studio, a capture card is usually added as a video source with the same tool you would use for a webcam: add a Video Capture Device source to a scene and pick the card from the Device list. Most modern USB capture cards present themselves to the operating system as a standard camera and audio input, so OBS treats them much like a webcam. One condition matters a great deal for speech: video showing up correctly does not mean the card's audio is reaching OBS. A camcorder sends sound over HDMI along with the picture, and you have to tell OBS how to handle that audio, or choose a separate microphone instead.

No specific capture card, camcorder or measurement was supplied for this guide. What follows is based on how OBS Studio's sources and audio settings generally work, not on hands-on testing of particular hardware. Menu names can vary between OBS versions and operating systems.

Capture card device vs. video capture device

On Windows and Linux, OBS does not use a separate source type for capture cards. On Windows, the Video Capture Device source covers webcams and capture cards alike. On Linux, the equivalent is usually listed as Video Capture Device (V4L2). Some recent macOS builds of OBS list a separate source aimed specifically at capture cards alongside the general Video Capture Device source. Because the details depend on the OBS version, check the source list in your copy and the release notes for that version rather than assuming one layout.

In practice, the choice of source type matters less than three other things: whether the card appears in the Device list, whether its resolution and frame-rate settings match what the camcorder outputs, and whether its audio is enabled and routed correctly. If one source type does not show the card or produces a black frame, try the other where your platform offers both.

Platform | Source to try first | Notes

Windows | Video Capture Device | Covers webcams and capture cards; audio handling is set in the source properties

macOS | Video Capture Device, or a capture-card-specific source if your OBS version lists one | Options differ by OBS and macOS version

Linux | Video Capture Device (V4L2) | Audio from the card is often added separately as an audio input capture source

Adding the capture card in OBS

• Connect the camcorder's HDMI output to the capture card and the card to the computer, then turn the camcorder on.
• In OBS, select your scene, click the plus button under Sources and choose Video Capture Device (or the capture-card source on platforms that have one).
• Name the source and select the capture card from the Device list.
• If the picture is wrong, black or stuttering, set Resolution/FPS Type to Custom and choose values the camcorder actually outputs.
• Close other apps that may be using the card; capture devices are often available to only one program at a time.
• Check the Audio Mixer to see whether a meter for the capture card moves when you speak near the camcorder.

Getting a clean picture from a camcorder

Many camcorders overlay menus, battery icons and recording indicators on their HDMI output. Look in the camcorder's display or HDMI settings for an option to turn off on-screen information; manufacturers name it differently, and some models do not offer it. Also check for automatic power-off or demo modes, which can stop the signal mid-session. Whether a given camcorder offers a clean, continuous HDMI feed depends on the model and was not covered by the supplied evidence.

Handling the camcorder's audio

HDMI can carry embedded audio, meaning sound travels in the same cable as the video. With a camcorder, that audio comes from its built-in microphone or from any external microphone plugged into the camcorder. For speech, the camcorder's built-in microphone has the same basic limitation as a webcam microphone: if it sits far from the speaker, it picks up more room echo and background noise relative to the voice. A microphone placed closer to the speaker usually gives clearer speech, whether it connects to the camcorder or directly to the computer.

On Windows, the Video Capture Device properties include an Audio Output Mode setting. Capture audio only sends the card's sound into the OBS mixer as part of that source, which is usually the right choice. The modes that output to desktop audio play the sound through your speakers instead. That can lead to the audio being captured twice, or to echo if a microphone hears the speakers. The same properties window also has a custom audio device option for cases where the card's audio appears as a separate input.

On macOS and Linux, the card's audio often appears as its own input device. Add it with an audio input capture source if it does not show up automatically in the mixer.

Keeping speech in sync and free of duplicates

• Pick one main speech source. Mute or remove any other microphone that hears the same voice, such as a webcam microphone or the camcorder's microphone when you use a separate mic. Mixing two microphones that pick up the same voice can make it sound hollow.
• If lips and voice drift apart, open Advanced Audio Properties from the Audio Mixer and adjust the Sync Offset for the microphone. This happens most often when the microphone connects directly to the computer while the video passes through the camcorder and capture card. Find the right value by testing; no figure applies to every setup.
• Avoid monitoring the capture card's audio through speakers while recording, or use headphones, so the microphone does not pick up the playback.
• Watch the meter while speaking at a normal level and set the gain so it stays well clear of the top of the scale.

Using the camcorder feed in a video call

To use the OBS scene in a conferencing app, start OBS's Virtual Camera and select it as the camera in the app. The virtual camera carries video only. In the conferencing app, choose a microphone separately: either the capture card's audio input, if the app lists it, or your dedicated microphone. If you want the call to receive audio processed in OBS, you need an extra audio-routing step outside the virtual camera. How well a given conferencing app handles that varies, and the supplied evidence did not cover it.

What this guide cannot confirm

No model-specific information was available. This guide cannot say which capture cards or camcorders work reliably together, how much delay a particular card adds, or how a camcorder's built-in microphone compares with a webcam microphone. Check those points in the documentation for your hardware and by making short test recordings before a live session.