How to save bandwidth with CDN caching for digital signage

The bandwidth problem

A common problem with digital signage is bandwidth. If you have 10 screens all showing the same video, it is downloaded 10 times — once per screen. This wastes bandwidth and can overload the network, especially at locations with a limited connection.

How DisplayFlow solves it

DisplayFlow uses a technique known as one-time download with local caching. It works like this:

1. When a playlist is updated, all media files are uploaded once to a CDN (Cloudflare R2)
2. Each player fetches the file from the CDN edge node closest to it
3. The file is cached locally on the player
4. During playback the file is played from the local cache — no bandwidth is used

Results

• First playback: the file is downloaded once
• Subsequent playbacks: 0 bandwidth — everything plays from the cache
• 10 screens, same video: 1 download instead of 10

When is the cache updated?

The cache is updated automatically when you replace a media file, add new media, or when the player restarts and validates against the server.

The player uses ETag-based cache validation, which means it only downloads the file if it has actually changed — not just because the player has restarted.

Tips for locations with a poor connection

1. Pre-compress media — use H.264 video instead of H.265 if the players are older
2. Allow time for downloading — publish playlists in advance so files have time to download before they are shown
3. Use images instead of video — images are smaller and load faster
4. Set up offline mode — the DisplayFlow player keeps showing cached media even if the network goes down

Summary

With smart CDN caching you can run dozens of screens on minimal bandwidth. DisplayFlow handles everything automatically — you do not need to think about caching, ETags or edge nodes. Just upload your files and let the system do the rest.