Walls and synced screens

A video wall is one stage whose screens together show one picture. You design one big canvas; every screen plays all of it and shows its own part, in step with the others. A synced group is different: several separate stages that each show their own picture, but change at the same moment.

Open the stage on Venue → Stages and choose how its screens hang:

• Grid — columns, rows and the size of one panel in pixels. Any size works, not only Full HD: an LED cabinet of 500 × 500 or a 32:9 bar. Bezel is the frame between two screens, in canvas pixels; that strip is hidden behind the frames, so a line crossing it stays straight.
• Free arrangement — for screens that are not a tidy grid, such as a portrait screen beside two landscape ones. Drag each panel to where it hangs (it snaps to its neighbors; hold Alt to place it freely), or type its position and size. Turn is for a screen hung on its side (see Mounting and rotation). Give each panel a name the installer will recognize. Panels may not overlap.

Only one panel plays sound — pick it under Sound plays from. The others play the same picture muted, so the wall never echoes itself.

Each panel needs its own device. Press Pair a screen and click the panel, or open the panel’s own link on its screen — the stage’s player link followed by /panel/<name>, or on a grid /cell/<column>/<row>, counted from 0, 0 at the top left. When the player starts, each panel shows its name for ten seconds: walk the wall and check the order.

You can also move the screens right on the design. Under Design for a wall, press Arrange panels: the design dims and each screen becomes an outline you drag into place (it snaps to its neighbors; Alt places freely; the arrow keys nudge, Shift by ten pixels). Hang any screen Landscape or Portrait, type its exact position and size, add a landscape or portrait screen, or remove one — so a portrait column beside two landscape screens is a few clicks. ⌘Z undoes a step; Cancel puts everything back.

Save… asks before it changes the wall: the arrangement is the wall’s, for every design and every screen on it, and the same checks apply as on the stage (no overlaps, at most 32 panels, 32768 pixels a side). Paired screens keep their panel; removing one a screen is on asks first and names the screen. When the wall’s size changes, choose Fit content to the new wall or Keep positions for the design you are in; other designs for the wall offer Match wall when opened.

Because every screen plays the whole slide on the same clock, anything can move across the wall:

• Video across the wall — drop one clip and stretch it across the screens. Every screen plays it and stays on the same frame.
• Motion — a title that flies in from the left edge of the wall and lands on the right, or shapes drifting across, cross the seams as one movement.
• Backgrounds — an animated gradient moves across the whole wall as one.
• Clocks show the same second on every screen.

Screens that are not one picture can still change together — the menu boards above a counter, or the screens along a corridor. Make a stage group of them and turn on Play in step. Each stage keeps its own content; a wall is always one such group by itself.

Every screen of a wall plays the whole design on the same clock — the Wunderframe server’s time, which each screen measures for itself. One screen is the leader: it decides what plays and the exact moment it starts. From that moment every screen works out each scene change on its own, so a change of scene needs no message at the moment it happens and lands at the same instant on every panel. The leader also says where it is, a few times a minute, and a screen that has drifted is pulled back into line.

Video gets extra care: the apps (Android TV, desktop, Raspberry Pi) open the next scene’s clips before the change, so every panel starts them together instead of each one late by however long its own player takes to start a video.

If the leader goes away, another screen takes over within seconds — nobody has to choose one. Under How the screens talk to each other pick one or more ways:

• Internet — through the Wunderframe server. Works anywhere, for browsers and apps alike. The default, and enough for most walls.
• Local network — panels running a Wunderframe app (Android TV, desktop or Raspberry Pi) talk to each other directly, so the wall stays together when the internet drops, and a panel that missed a download gets the file from the leader. Browsers cannot use it.
• Media room — a fast data channel over the internet, for the tightest sync between browsers or across sites.

A new wall uses Internet and Local network together. Keep at least one way every panel can use: a browser panel in a group that only uses the local network hears nobody and plays on its own.

A panel that got out of step — after a power cut, a network hiccup, or a player that was busy — normally catches up by itself within a few seconds. To line the whole wall up at once, press Sync wall now on the wall’s card on Venue → Stages. Every screen of the wall fetches what plays again and re-reads the shared clock; what is on screen keeps playing, nothing reloads, and the panels line up within a few seconds.

If one panel keeps drifting, open Devices: every panel of a healthy wall shows the same leader, and a screen whose clock is far off says Clock off. Keep the players up to date — a new player or renderer takes effect after its next reload.

A changed story first downloads onto each screen; the screens switch to it only when it is complete, so no screen shows half-loaded content. When new content arrives decides how long the others wait for a slow panel:

• Wait for every panel — the default. The new version plays only once all panels have it, and they switch together at the next loop.
• Wait, up to a deadline — after the Deadline in seconds, the ready screens switch and a late panel plays the missing files from the internet and joins at the next loop.
• Don’t coordinate — each screen switches as soon as it is ready. Fine for screens nobody sees side by side.

Browser panels need nothing on the local network. App panels (Android TV, desktop, Raspberry Pi) that sync directly need these between the panels of one wall:

• The multicast group 239.77.70.1, UDP port 47770 — the panels find each other and keep time.
• TCP port 47771 on every panel — the leader shares its saved content with the others when the internet is down.
• All panels in the same network segment (subnet or VLAN) — multicast does not cross routers.
• Client isolation off — guest and hotel Wi-Fi often stop devices from seeing each other. Prefer a cable for walls.
• On managed switches with IGMP snooping, an IGMP querier must be on, or the group is dropped after a few minutes.

On Devices, every panel of a healthy wall shows the same leader.