From cf24a3e0d6da790eee790592c82e510aade05e12 Mon Sep 17 00:00:00 2001 From: Josh Hawkins <32435876+hawkeye217@users.noreply.github.com> Date: Sat, 18 Jul 2026 07:11:39 -0500 Subject: [PATCH] add faq about preview restart cache --- docs/docs/troubleshooting/recordings.md | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/docs/docs/troubleshooting/recordings.md b/docs/docs/troubleshooting/recordings.md index c4e8e72b2..372c7b8dc 100644 --- a/docs/docs/troubleshooting/recordings.md +++ b/docs/docs/troubleshooting/recordings.md @@ -428,3 +428,19 @@ You'll want to: - [Tune your motion detection settings](/configuration/motion_detection) either by editing your config file or by using the UI's Motion Tuner. + + + +The scrubbing previews (the timelapse clips shown when dragging the History timeline, the secondary-camera previews, and the preview that plays when hovering a review card) are not recorded continuously. Frigate caches low-resolution preview frames in `/tmp/cache` throughout each hour and only assembles them into a finished preview clip **at the top of the hour**. + +In the recommended configuration, `/tmp/cache` is a small in-memory (`tmpfs`) area. When Frigate starts, it tries to restore the current hour's cached frames, so a **soft restart from the UI** preserves them. But if you recreate the Docker container or stop Frigate forcibly by any other means partway through an hour, the in-memory cache is discarded, so no preview clip is produced for that partial hour. + +This is expected behavior, not a bug: + +- Previews for hours that already completed and were written to disk are unaffected. +- The next full hour after a restart will generate previews normally. +- This is unrelated to `shm_size`; increasing shared memory does not change it. + +To avoid the gap, use the **Restart Frigate** button in the UI's Settings menu rather than recreating the container when possible. + +