Short answer
Start with one file and one client
Enter a full local file path in Plex's Movie pre-roll video field, then enable Cinema Trailers in both the relevant movie library settings and the player app. Prove one file on the client you will use before adding sequential or random choices.
- Baseline
- Use one short file for the first check; add another path only after the first pre-roll appears reliably on the intended client.
- Caveat
- Plex app labels and feature availability can change, and a setup that works on one server-and-player combination is not proof for every client or version.
Treat the setting as one part of a chain
Plex documents a Movie pre-roll video field in its server Extras settings. The field accepts the full local path to a video file, but the path alone is not the complete setup. Plex also says Cinema Trailers must be enabled in the player app and the relevant advanced setting must be enabled for the movie library.
Check those three locations before diagnosing the video itself: the server Extras field, the advanced settings for the library that contains the feature and the Cinema Trailers option in the player that will start playback. Use Plex's current labels on your installation if they differ from the documentation. Do not assume another player has inherited the same choice.
| Layer | What to confirm | Why it belongs in the test record |
|---|---|---|
| Server | The Movie pre-roll video field contains a full local path | It identifies the configured file |
| Movie library | The relevant advanced Cinema Trailers setting is enabled | The feature is being started from this library |
| Player app | Cinema Trailers playback is enabled | Availability and labels can vary by client and version |
Enter one full path first
Choose a short local video you created, licensed or otherwise have permission to play. Put its full local path in the Movie pre-roll video field. A single-path first pass removes ordering and random selection from the diagnosis. If the pre-roll does not appear, you have one file and three required settings to inspect rather than a whole cue package.
The path should describe the file where Plex Media Server can reach it. Do not replace a full path with a web address or a title from the library; that is not what the documented field requests. Keep the filename simple for the first check and record the exact server and player versions beside it. That record lets you distinguish a later application change from an unexplained memory of what once worked.
This guide does not provide a downloadable pre-roll. It also does not make an arbitrary trailer, studio bumper or music recording reusable. The planning rule is straightforward: use media you created, licensed or otherwise have permission to play, and do not redistribute files simply because they can be referenced locally.
Use commas for a sequence and semicolons for a random choice
Plex's Extras documentation assigns different behavior to the two separators. Put commas between full paths when you want the listed videos to play sequentially. Put semicolons between paths when you want Plex to choose one of them at random.
| Intent | Field pattern | Timing consequence |
|---|---|---|
| Play both in order | /media/leader.mp4,/media/countdown.mp4 | Reserve time for both videos and their transition |
| Choose one | /media/leader-a.mp4;/media/leader-b.mp4 | Reserve enough time for the longest candidate |
Those paths are syntax examples, not files supplied by this site. For the first setup, do not mix a sequential plan and a random pool. Prove one behavior, measure it, then make the field more complex only if the added variation earns its maintenance time. A fixed two-file sequence is easier to schedule; a random pool avoids showing the same cue every evening but requires a budget that accommodates its longest member.
Run one controlled test on the intended client
- Choose one short, permitted local video and note its full path.
- Enter only that path in the Movie pre-roll video field.
- Confirm the relevant advanced setting in the movie library.
- Enable Cinema Trailers in the player app you intend to use.
- Start a movie from that library on that player and observe whether the pre-roll appears.
- Time from the pre-roll's first visible frame to the feature's actual start.
Record the result without turning it into a broad compatibility claim. A useful note names the server version, the player app and version, the library, the configured path and the observed feature start. If nothing plays, return to the single-path state and re-check each dependency. If it works, repeat on the same client before adding a comma or semicolon list.
Test every client that matters separately. A successful run on one television app does not establish that another app exposes the same label or supports the same behavior. When Plex changes a setting name or a client stops offering the option, consult the current official pages rather than forcing an older set of menu directions onto the new interface.
Put the observed runtime on the cue sheet
A pre-roll is still part of the schedule even when Plex starts it automatically. Enter the observed span in thepre-show run-sheet builder, including the transition into the feature. For a comma-separated sequence, budget every file. For a semicolon-separated random set, use the longest candidate so the promised feature time is protected regardless of the choice.
If you are still deciding whether trivia or trailers deserve those minutes, use thetrivia, trailers and timing guide before expanding the field. Plex can start prepared videos; it cannot decide whether guests would rather keep talking or whether the sequence should be cut because the evening is late.
Keep a manual fallback. The narrow goal is a repeatable cue before the feature, not dependence on one setting. If the client or version changes, remove the automated block from that evening's run sheet until the current combination has been checked again.