diff --git a/docs/docs/configuration/advanced.md b/docs/docs/configuration/advanced.md
index ea8e8f3d8..8e6727bcd 100644
--- a/docs/docs/configuration/advanced.md
+++ b/docs/docs/configuration/advanced.md
@@ -76,3 +76,5 @@ To do this:
 1. Download your ffmpeg build and uncompress to a folder on the host (let's use `/home/appdata/frigate/custom-ffmpeg` for this example).
 2. Update your docker-compose or docker CLI to include `'/home/appdata/frigate/custom-ffmpeg':'/usr/lib/btbn-ffmpeg':'ro'` in the volume mappings.
 3. Restart frigate and the custom version will be used if the mapping was done correctly.
+
+NOTE: The folder that is mapped from the host needs to be the folder that contains `/bin`. So if the full structure is `/home/appdata/frigate/custom-ffmpeg/bin/ffmpeg` then `/home/appdata/frigate/custom-ffmpeg` needs to be mapped to `/usr/lib/btbn-ffmpeg`.