How to connect ProPresenter and media servers to an LED wall

Playback computers do not “just work” on LED. ProPresenter, Watchout-class systems, and other media servers are built for projectors and house screens. An LED wall has a native pixel map that is rarely 1920×1080, a processor that will happily scale twice, and a congregation that can read every soft lyric.

This tutorial covers how to connect playback to the processor, how to build screens that match the wall, and how to keep a spare computer ready. It is educational and not affiliated with any software vendor. Menu names change between versions; the signal path does not.

Pick one program path and one backup path

Choose the physical link from the playback machine to the processor:

For most churches, the clean pattern is: ProPresenter → SDI (or a quality HDMI-to-SDI) → switcher or straight to the LED processor program input. A second machine hits the processor’s backup input.

Do not put a consumer HDMI splitter as the only fan-out to IMAG, record, and LED. Use a distribution amplifier or the switcher.

Lock the output format before you build pretty slides

On the playback computer:

1. Set the GPU / capture-output resolution to the format you agreed with the processor tech — often 1920×1080p59.94, or a custom timing if you are driving the wall pixel-to-pixel.
2. Disable any OS “HiDPI” or Retina scaling on that output. You want 1920 pixels, not a 1920-looking desktop that is actually 3840.
3. Turn off screen savers, sleep, and notification banners on the show machine.
4. Confirm the processor sees a locked signal at that exact rate.

If the LED canvas is 2016×1152 and you can output that timing from the server, do it and build the ProPresenter screen at 2016×1152. If you cannot, output 1920×1080 and let either ProPresenter or the processor scale — not both.

Single scaler rule: pick one. Double scaling makes mushy type and drifting edges.

Build screens and safe areas for LED

In ProPresenter-style software you typically create a screen or device for the LED wall. Set it to the output that hits the processor. Then:

• If the wall is not 16:9, draw a custom screen at the wall’s native pixels, or draw a 16:9 screen with a documented crop.
• Keep lyrics in a safe area that is not sitting on a cabinet seam if that seam is optically busy (arches, missing corners).
• Avoid 1-pixel outlines and hairline rules. They beat with the pixel grid and vanish at a distance.
• Prefer larger type and more weight over “it looked fine on the projector.”
• Test lower-thirds against IMAG. A caption that sits on a person’s hairline on the wall may be fine; one that sits on the pixel-grid horizon may shimmer.

Media servers that think in layers (background, IMAG window, lyrics) should match the processor layer plan. If the processor already windows IMAG, do not also window it in the server unless you like two rectangles.

Color, audio, and clocks

• Set the output to Rec. 709 / legal or full range to match the processor. A full-range Mac desktop into a limited SDI path crushes logos.
• Mute audio on the LED output. Walls do not need program sound; a digital path that embeds audio can still surprise a processor.
• If the house is genlocked, genlock the server or accept that lyrics may tear against IMAG. For most churches, a stable 59.94 free-run is enough if everything matches that rate.
• Turn off motion smoothing and HDR tone-mapping on the GPU.

Export a 1-pixel grid and a circle as a test look. Keep it in the house library.

NDI and networked playback

NDI is useful when the ProPresenter machine cannot sit next to the processor. It is not free:

• Use a dedicated VLAN or at least a switch that is not also the church Wi-Fi.
• Budget bandwidth: 1080p NDI is not “a little extra” on a 1 Gb shared office switch.
• Watch latency. IMAG-plus-NDI-plus-LED-scaler can stack frames. Talent notices.
• Have an SDI or HDMI fallback. Networks get “optimized” by well-meaning IT.

If you use NDI only as a convenience to the back hallway, test it under full Sunday load (IMAG, streaming, recording).

Two-machine redundancy that people will actually use

The professional pattern:

1. Show machine A is program.
2. Show machine B runs the same document from a synced folder or a mirrored show.
3. An operator can switch the processor input or a small router in one button.
4. Both machines use the same EDID-derived format.

Sync the show files on a schedule, not by hope. A USB stick with last week’s document is a valid emergency if cloud sync failed.

Name the machines and the processor inputs the same way: PP-A, PP-B. Put it on the rack label.

Guest laptops

Guests will bring 4K, 30 Hz, and Keynote in 16:10. Your job is to protect the wall:

• Provide a labeled laptop input that hits a scaler before the LED canvas, or a dedicated processor layer with “keep aspect.”
• Do not let a guest HDMI become the EDID master for the whole processor.
• Have a house slide that says “guest input” so the operator knows they left the house file.

A campus that hosts frequent guests should keep a small hardware scaler on that input. It is cheaper than rebuilding the canvas live.

Common mistakes

Designing every look at 1920×1080 on a 1536-pixel-wide wall and wondering why the side logos are gone.

Mirroring the desktop so notifications and the mouse appear on the IMAG wall.

Using Wi-Fi to remote the show computer as the only control path. Bring a wired KVM or sit in the booth.

NDI through the same cheap switch as LED receiving-card data. Two different networks, please.

Updating ProPresenter on Saturday night. Do that after the series, on the backup machine first.

Forgetting that alpha and transparency can expose the wrong layer on LED (a hole to black or to a test pattern).

Pre-service playback checklist

• Output format locked and matches the processor
• Only one scaler in the path
• Screen size matches the written canvas plan
• Notifications and sleep off
• Backup machine on and in the same document
• Guest input isolated
• Grid/circle test once after any cable change
• First real lyric slide checked from row two

When playback tells the truth about pixels, the wall looks like a display instead of a projector that someone stretched.