Check ffmepg path, use proper health endpoint

root/etc/s6-overlay/s6-rc.d/svc-jellyfin/run

@@ -1,4 +1,9 @@
 #!/usr/bin/with-contenv bash
+# shellcheck shell=bash
+
+if [[ -z "${FFMPEG_PATH}" ]] || [[ ! -f "${FFMPEG_PATH}" ]]; then
+    FFMPEG_PATH=/usr/lib/jellyfin-ffmpeg/ffmpeg
+fi
 
 export \
     JELLYFIN_DATA_DIR="/config/data" \
@@ -8,6 +13,6 @@ export \
     JELLYFIN_WEB_DIR="/usr/share/jellyfin/web"
 
 exec \
-    s6-notifyoncheck -d -n 300 -w 1000 -c "nc -z localhost 8096" \
+    s6-notifyoncheck -d -n 300 -w 1000 -c "curl -s --output /dev/null http://localhost:8096/health" \
         s6-setuidgid abc /usr/bin/jellyfin \
-        --ffmpeg=/usr/lib/jellyfin-ffmpeg/ffmpeg
+        --ffmpeg="${FFMPEG_PATH}"