# OBS Capture Card Setup Guide ## Capture Card — OBS Projector Method This is the **recommended** capture card setup. It uses OBS Fullscreen Projector to send the game feed to the capture card, which means your gaming resolution and refresh rate are completely independent from what the capture card receives. You can play at 1440p 480Hz while the capture card gets a clean 1080p 240Hz signal. > **Projector vs Passthrough:** With passthrough, your gaming monitor is limited to whatever the capture card supports. With OBS Projector, the capture card acts as its own separate display — no limitations on your main monitor. OBS Projector is the recommended method for this reason. *** ### Prerequisites #### Capture Card Requirements Not all capture cards work well for this use case. Streaming and 2PC AI/color detection are very different workloads. A card that's fine for Twitch streaming may perform terribly here. **What you need:** * A capture card that supports **1080p @ 240 FPS** (or at minimum 1080p @ 120 FPS) * **NV12** color format support * Low latency — budget/generic cards from Amazon often run at 50–60 FPS with high latency, which makes AI detection unusable **Recommended cards:** * **Elgato 4K Pro** (PCIe) — lowest latency, best option if your Script PC has a PCIe slot * **Elgato 4K X** (USB) — very close to PCIe performance, but requires a **USB 3.1 Gen 2 or USB 3.2 Gen 2** port * **AVerMedia GC573 / GC553G2** — solid alternatives > **USB-C doesn't mean Gen 2.** If you're using a USB capture card, verify the port is actually Gen 2. On a Gen 1 port, you'll be stuck at 120 FPS instead of 240 FPS. Check your motherboard specs. > **PCIe slot bandwidth matters.** If you're using a PCIe capture card, make sure it's in an adequate slot. A PCIe x1 slot may be bandwidth-limited. Check your motherboard manual to confirm the slot speed. If capture FPS is lower than expected, try reseating the card in a different slot. *** ### Step 1: Install the Capture Card (Script PC) The capture card goes in the **Script PC** — the PC that handles processing and detection. Not the Gaming PC. 1. Install the capture card in the Script PC's PCIe slot (or connect via USB if using a USB card). 2. **Update the firmware** from the Script PC. Visit the manufacturer's support page ([Elgato](https://www.elgato.com/downloads) / [AVerMedia](https://www.avermedia.com/support) / [Magewell](https://www.magewell.com/downloads)) for firmware tools and drivers. 3. **Reboot the Script PC** after updating firmware before continuing. *** ### Step 2: Connect the Hardware 1. Connect an **HDMI cable** from your **Gaming PC GPU output** → **HDMI IN** on the capture card (installed in the Script PC). 2. Your gaming monitor stays plugged into the Gaming PC GPU as normal. The capture card will appear as a second monitor on the Gaming PC. *** ### Step 3: Configure the Capture Card Display (Gaming PC) #### Set Windows to Extend Displays Go to **Windows Display Settings** and set the display mode to **Extend these displays**. > **Do not use Duplicate.** Duplicating forces both displays to the lowest common denominator — this can cap your gaming monitor's refresh rate to whatever the capture card supports. Extend keeps them independent. #### Set the Capture Card Resolution 1. Open **NVIDIA Control Panel** or **Windows Display Settings → Advanced Display**. 2. Select the capture card display (it shows up as a second monitor). 3. Set the resolution to **1920×1080**. 4. Set the refresh rate to **240 Hz** (or the highest your capture card supports). 5. Apply and confirm. #### Verify Active vs Desktop Signal (Important) This step catches scaling issues. If the active signal doesn't match the desktop signal, Windows is scaling the output, which degrades quality. 1. Go to **Windows Settings → System → Display → Advanced display**. 2. At the top, select your **capture card display** from the dropdown. 3. Look at the information shown — you should see both **Active signal** and **Desktop resolution** listed. 4. Both should show **1920 × 1080, 240 Hz** (or your chosen settings). If they don't match, go back and adjust the resolution/refresh rate until they do. > **Where to find this:** It's in Windows Settings, not NVIDIA Control Panel. Go to Settings → System → Display → scroll down → Advanced display → select the capture card display from the dropdown at the top. You'll see "Active signal resolution" and "Desktop resolution" listed there. *** ### Step 4: Configure OBS (Gaming PC) #### Install and Open OBS Download and install [OBS Studio](https://obsproject.com/) on the **Gaming PC**. Make sure your GPU drivers are up to date. #### Video Settings Navigate to **Settings → Video** and set: * **Base (Canvas) Resolution:** `1920x1080` * **Output (Scaled) Resolution:** `1920x1080` * **FPS:** Fractional `240/1` * **Color Format:** `NV12` > **Why 1080p for capture cards?** Unlike NDI/UDP where lower resolutions save bandwidth, capture cards handle 1080p natively without network overhead. 1080p gives better detection accuracy at longer distances since targets are less pixelated. This is the standard setting for capture card setups. #### Add Game Capture Source 1. In the **Sources** panel, click `+` and select **Game Capture**. 2. Set **Mode** to `Capture Specific Window` and select your game (must be open). 3. Select the Game Capture source in Sources, then press `Ctrl + D` to center it on the canvas. > **Use Game Capture, not Display Capture.** Game Capture is significantly better for performance and quality. Display Capture introduces additional overhead and latency. Only fall back to Display Capture if Game Capture doesn't work with your specific game. #### Set Up Fullscreen Source Projector (Critical Step) This is how you send the OBS output to the capture card. 1. In the Sources panel, **right-click your Game Capture source**. 2. Select **Fullscreen Projector (Source)** → choose your **capture card display**. > **Use Source Projector, NOT Preview Projector.** This is a common mistake. Preview Projector can cause the crosshair to appear off-center in the debug view. Source Projector sends the raw game capture directly to the capture card display, properly centered and scaled. If your crosshair is off-center, switching from Preview to Source Projector fixes it. > **Can't find the Fullscreen option?** The right-click menu just says "Projector" — the fullscreen option is part of the submenu. Right-click → Fullscreen Projector (Source) → select display. #### Disable the OBS Preview Right-click on the OBS preview area and select the option to **disable the preview** to reduce GPU usage on the Gaming PC. *** ### Step 5: Configure the Application (Script PC) 1. Set **Capture Mode** to **Capture Card** in the capture tab. 2. Select the correct **capture source/device**. If you see your webcam instead of the game feed, you have the wrong device selected — cycle through the available devices until you see the game. 3. Set the capture format to match: **1080p 240 FPS NV12**. If this isn't available in the dropdown, use the custom option and enter `1920x1080 @ 240fps (NV12)` manually. 4. Load a community config set to capture card mode. 5. Press Start. The debug window should show the live game feed. > **Webcam showing instead of game?** This means the wrong capture device is selected. The capture card might be listed as "device 0", "device 1", etc. — try different device indices until the game feed appears. If no devices show the game, the capture card may not be plugged in properly or Windows isn't recognizing it. *** ### Troubleshooting #### No signal / debug view is black **1. Check HDMI connection.** Make sure the HDMI cable goes from the Gaming PC GPU → HDMI IN on the capture card. Not the other way around. **2. Verify the capture card shows as a display on the Gaming PC.** Open Windows Display Settings — you should see two monitors. If the capture card doesn't appear, it's not properly connected or recognized. **3. Check that you started the Source Projector.** In OBS, right-click the Game Capture source → Fullscreen Projector (Source) → select the capture card display. The projector window should open on the capture card display. **4. Verify display mode is Extend.** Duplicate mode can cause issues. Set to Extend these displays. #### Low capture FPS (e.g., 36 FPS when expecting 240) **1. Check the capture card resolution/refresh on the Gaming PC.** In Windows Advanced Display settings, select the capture card display. Active signal should show 1920×1080 240Hz. If it shows something lower (like 60Hz), the resolution or refresh rate settings are wrong. **2. USB card on wrong port.** If using a USB capture card, verify it's plugged into a USB 3.1/3.2 Gen 2 port. On a Gen 1 port, you're limited to \~120 FPS. **3. PCIe slot bandwidth.** If using a PCIe capture card and getting unexpectedly low FPS, try a different PCIe slot. Some x1 slots are bandwidth-limited. **4. Cheap capture card limitations.** Generic/budget cards often max out at 50–60 FPS regardless of settings. If your card can't do NV12 at 1080p 240Hz, it may not be suitable. Check what formats and resolutions are actually available in the application's capture settings dropdown. **5. Capture format mismatch.** In the application's capture settings, make sure the format is set to NV12 at 1080p 240. If NV12 isn't available for your card, try YUY2 as a fallback. #### Crosshair off-center in debug view Switch from **Preview Projector to Source Projector**. Right-click the Game Capture source (not the preview) → Fullscreen Projector (Source) → select capture card display. #### Webcam showing instead of game feed The wrong capture device is selected in the application. Change the device index (device 0, device 1, etc.) in the capture settings. If none show the game, the capture card isn't being recognized — check the physical connection and that firmware/drivers are installed. #### Game running in fullscreen causes issues Some games in exclusive fullscreen mode can conflict with OBS Game Capture or cause the projector output to break. Try running the game in **Borderless Windowed** mode. OBS Game Capture in "Capture Specific Window" mode generally handles this, but borderless windowed is the safer option. #### Capture backend not working The application offers different capture backends: `opencv`, `ffmpeg`, and `libav`. If one isn't working (low FPS, freezing, errors), try the others. Stop, switch the backend, then Start again. #### Stuttery aim despite high capture FPS Capture FPS and detection FPS are different from the debug display FPS. Check all three values in the debug view: * **Capture FPS** — how fast frames come from the capture card * **Detection FPS** — how fast the model processes them * **Debug display FPS** — just the display refresh (cap this at 60 FPS with scale 0.5 to reduce overhead) If capture FPS is high but detection FPS is low, the bottleneck is your Script PC's GPU or model, not the capture card. *** ### Quick Reference | Setting | Location | Value | | -------------------------- | ----------------------------------------- | --------------------------- | | Capture card installed in | Script PC | PCIe slot or USB Gen 2 port | | HDMI cable | Gaming PC GPU out → Capture card HDMI IN | — | | Windows display mode | Gaming PC Display Settings | Extend these displays | | Capture card resolution | Gaming PC NVIDIA/Display Settings | 1920×1080 @ 240 Hz | | Active = Desktop signal | Gaming PC Advanced Display | Must match | | OBS Base/Output Resolution | Settings → Video | `1920x1080` | | OBS FPS | Settings → Video | `240/1` (fractional) | | OBS Color Format | Settings → Advanced | `NV12` | | OBS Projector | Right-click Source → Fullscreen Projector | Capture card display | | App Capture Mode | Script PC capture tab | Capture Card | | App Capture Format | Script PC capture tab | `1080p 240 NV12` | --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. 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