Green-screen HDMI output for hardware switchers

OBS can take a transparent browser source, but a hardware switcher can't. It takes video in over HDMI and has no idea what a web page is. For that setup ScoreCastr has a green-screen version of each overlay channel: a computer shows it full screen, its HDMI output goes into the switcher, and the switcher's chroma key removes the green so only the graphics sit on top of your cameras.

What you need

• A computer just for graphics output, or a spare display output on the dashboard computer. A dedicated machine is safer: nothing else pops up on air.
• An HDMI cable from that output into a switcher input.
• A switcher with a chroma key (sometimes called a keyer or green-screen key) on that input.
• The match open on the dashboard on any computer. The output computer only shows the overlay; scoring can happen anywhere.

HDMI Output is on every plan, including Free.

Open the HDMI output

1. On the match's Control Dashboard, open Overlays, then Live Preview.
2. In the OBS Integration card, click HDMI Output in the Channel 1 row. A new tab opens with your graphics on solid green.
3. If you use Channel 2 as well, its row has its own HDMI Output. See Use two output channels.

The HDMI link is the channel's normal overlay link with &greenscreen=true added at the end. If you're setting up a separate output computer, copy the address from the new tab and open it there, or click Copy Channel 1 URL and add &greenscreen=true to the end yourself.

Put it on the switcher input

1. Move the browser window to the display that feeds the switcher. On a computer with one HDMI port, set that port as an extended display.
2. Set that display to 1920 by 1080 and its scaling to 100%. The graphics are laid out for a 1080p frame in exact pixels; a smaller resolution or a higher scaling setting crops them or pushes them out of place.
3. Keep the browser zoom at 100%.
4. Make the window full screen, so no tabs, address bar or taskbar show. In Chrome or Edge on Windows press F11; on a Mac use View, then Enter Full Screen.
5. Move the mouse pointer off that display.

The green fills the whole frame. Until the match loads, and whenever no graphic is switched on, the output is plain green, which keys to nothing.

Key out the green

1. On the switcher, choose the HDMI input as the key source for an upstream or downstream key.
2. Set the key type to chroma (green screen).
3. Sample the green, or enter it by hand: #04F404 (red 4, green 244, blue 4).
4. Adjust until the green is gone and the graphics edges are clean, then turn the key on over your program.

Bring a graphic on air from the dashboard to tune the key with something to look at: the scorebug is on from the start, and with the Starter plan the Go to Break button gives you the full-screen scoreboard.

Tips for a clean key

• Watch for green in your graphics. Anything close to the key green, like a bright green team color, disappears with it. Pick a darker or different shade for that team, or check it before air.
• Soft edges pick up green. Shadows, glows and see-through panels mix with the green behind them. Use the switcher's spill or edge controls to clean them up rather than widening the key until it eats the graphics.
• Turn off pop-ups. Notifications, update prompts and screen savers on the output computer will appear on air. Turn them off, and set the computer not to sleep.
• Test the animations. A goal or touchdown takeover moves fast across the bar. Watch one through the key before the game to see that the edges hold up.

Fix common problems

The output shows the browser window, not full screen. Press F11 again (or use the full-screen menu) with that window active.

Graphics are cut off or too big. The output display isn't 1920 by 1080 at 100% scaling, or the browser is zoomed. Fix those first.

The green has no graphics on it. Check that the graphic is switched on in the Overlay Visibility panel (Starter plan) and assigned to the channel you opened. Also check the link: each match has its own, so last week's HDMI tab shows last week's match.

The overlay stopped updating. Look at the status dot on the dashboard. If it says Live, reload the HDMI tab on the output computer, then make it full screen again. More fixes are in Overlay not showing or not updating.

Checklist

• HDMI Output opened for the right match and channel
• Output display at 1920 by 1080, 100% scaling, browser zoom 100%
• Window full screen, mouse pointer off the display
• Chroma key set to #04F404 and tuned with a graphic on air
• Notifications and sleep turned off on the output computer