Offline, caching and storage

A screen in a venue will lose its network sooner or later. Wunderframe is built so that nobody in the room notices: a player keeps what it needs on the device and never shows black.

A player keeps the stage’s plan for the coming hours and every image, video, font and sound file in it on the device. When the network drops it plays on from what it has — the call sheet keeps changing at the right times, from the device’s own clock.

• A browser keeps it in the browser’s storage and asks to keep it permanently. Do not use a private or guest window: its storage is wiped when it closes.
• The apps — Android TV, desktop and Raspberry Pi — keep it on the device’s disk and play video from there, so video still seeks and loops offline, and the program plays at once after a reboot.

Records, rolling lists and feeds travel with the program as a small data package the server prepares. Pictures a feed links from another site are fetched once by Wunderframe and stored like your own media, so a screen never depends on that site at the moment it shows them. Offline, a screen shows the last data it had — never an empty block — and a block that can says updated 07:30. New data joins the same switch as new content, so a wall’s panels show it at the same moment.

When you change a story, each screen downloads the new version while it keeps playing the old one, and switches only when every file has arrived. On a wall all panels switch together — see When new content arrives. On Devices, an arrow to a second version on a device means it is still downloading.

• For a few minutes — the screen plays on as before. After a minute a small marker appears in a corner, so a technician can tell.
• For longer — it keeps playing the last plan it had, and retries in the background, less often the longer it lasts.
• Back online — it reports in at once and catches up with anything that changed.

A live take made while a screen is offline reaches it when it comes back. Presenters need the network: their video cannot play offline.

The player always keeps some room free for the device — 500 MB or a tenth of the disk, whichever is larger. When the rest is not enough, it plays what it has and streams the rest from the network, and Devices shows Some files stream or Storage full. It never deletes a file the screen is playing now or is about to play.

Plan free space of at least twice the media booked on the stage. Video is what counts: ten minutes of Full HD video is roughly 0.5 to 1 GB. Android TV boxes often have 8 GB with half used by the system — check Settings → Storage on the box before the event.

A player never shows black on purpose. Nothing scheduled shows the idle card with what comes next; a failed download keeps the last thing that worked; a player that hangs restarts itself. Every screen also restarts once a day — at 04:00 venue time unless you set another time on Devices — to start each day fresh.

After a power cut or a reboot, an app shows the Wunderframe startup animation while it gets ready — Getting this screen ready… 12 of 18 files — and switches to the program only once it has what it needs.