Synchronized playback across screens

Introduction

A playlist assigned to several screens normally runs on each screen's own timer, so the screens drift apart. Synchronized playback (FI: Synkronoitu toisto) makes them play in step, driven by the clock: every screen computes its position from the current time, so nothing needs to talk to anything else, and screens fall back into formation on their own after a reboot or power cut. You can also stagger the screens so that each one shows a different slide at the same moment.

What needs to be true

Sync has a few hard requirements, and the panel tells you when one isn't met:

• Each screen shows only this playlist. Sync needs the playlist to be the screen's whole rotation: assigned directly, or as the only slide on the screen, without a schedule on that slot. If a screen has other content, the panel lists it under "These screens have other content".
• Every video has a duration. All screens must agree on how long the loop is, so each video needs a set length. InfoBox reads it from the file automatically; only a video whose length can't be determined blocks, and the panel names it.
• The playlist is assigned to at least one screen.
• Device app version 1.0.35 or newer. Older devices are listed with "Update the app on: ...". They keep playing, just not in sync.
• Sync isn't tied to a plan or role: anyone who can edit the playlist can set it up.

The three modes

Open the playlist editor and click Synchronized playback in the toolbar. Pick one card:

• No sync (FI: Ei synkronointia): each screen runs on its own timer. The default.
• Same slide everywhere (FI: Sama sisältö kaikilla): all screens show the same slide at the same time. Right for video walls, a row of identical screens, or a campaign that should hit every screen at once.
• Stagger screens (FI: Porrasta näytöt): each screen starts at a different point in the loop, so the same slide never shows on two screens at once.

Stagger patterns and screen order

With Stagger screens selected, two more choices appear:

• Spread evenly (FI: Tasainen jako): the loop is divided by the number of screens and the screens are spaced equally around it, whatever the slide lengths.
• One slide apart (FI: Yksi kerrallaan): screen 2 shows what screen 1 showed one slide ago, screen 3 two slides ago, and so on. A message visibly walks down the wall, and handovers land on real slide boundaries even with mixed durations.
• Screen order (FI: Näyttöjen järjestys): drag the screens into their physical order. The first screen leads, the others follow.

Save, then publish

The selection is a draft until you publish:

• Click Save selection (FI: Tallenna valinta). The toast reads "Sync selection saved. Publish the playlist to apply it." and an Unpublished chip appears next to the panel title.
• Click Publish on the playlist. The Platform re-checks the requirements, applies the offsets to every screen, and resyncs them. All screens cut to the first slide together.
• The toolbar button then shows Synced or Staggered.
• Re-publishing an already synced playlist re-anchors the formation, so it doubles as a "resync now" button.
• If the check fails at publish time, the content is still published but the panel shows a red Sync not applied state with the reason (other content on a screen, or a video without a duration). Fix it and publish again.

Keeping screens in sync

Once running, the Platform protects the formation:

• Opening Add new slide on a synced screen shows an amber warning: adding content there takes the screen out of sync with the others, and the Platform refuses to add a slide to a screen locked to a live-synced playlist.
• Assigning a synced playlist to a screen that already has other content is refused: "A synchronized playlist can only be assigned to a screen that has no other content."
• Devices with a wrong clock still line up: each device learns the server time on every check-in and corrects for its own drift.
• After a reboot, power cut, or app update, a screen is back in formation within one slide.

Different slides at the same moment

Combine sync with the per-screen slide order to hand-pick what each screen shows:

• Click Slide order per screen at the bottom of the sync panel.
• Each screen gets a column; drag slides within a column. Slides on the same row play at the same time on synced screens.
• Every screen still plays the same set of slides, so the loops stay the same length and the screens stay in step.
• Full details: see Assigning playlists to screens.

Summary

Pick Same slide everywhere or Stagger screens, save, publish. Sync needs each screen to show only this playlist and every video to have a duration. Screens stay in step from the clock and recover on their own.