diff --git a/transcoder/main.go b/transcoder/main.go
index 152b0972..2c3d20db 100644
--- a/transcoder/main.go
+++ b/transcoder/main.go
@@ -176,13 +176,10 @@ func (h *Handler) GetInfo(c echo.Context) error {
 		return err
 	}
 
-	ret, err := src.GetInfo(path, sha)
+	ret, err := h.metadata.GetMetadata(path, sha)
 	if err != nil {
 		return err
 	}
-	// Run extractors to have them in cache
-	src.Extract(ret.Path, sha)
-	go src.ExtractThumbnail(ret.Path, sha)
 	return c.JSON(http.StatusOK, ret)
 }
 
@@ -246,13 +243,12 @@ func (h *Handler) GetThumbnails(c echo.Context) error {
 	if err != nil {
 		return err
 	}
-
-	out, err := src.ExtractThumbnail(path, sha)
+	sprite, _, err := h.metadata.GetThumb(path, sha)
 	if err != nil {
 		return err
 	}
 
-	return c.File(fmt.Sprintf("%s/sprite.png", out))
+	return c.File(sprite)
 }
 
 // Get thumbnail vtt
@@ -266,17 +262,17 @@ func (h *Handler) GetThumbnailsVtt(c echo.Context) error {
 	if err != nil {
 		return err
 	}
-
-	out, err := src.ExtractThumbnail(path, sha)
+	_, vtt, err := h.metadata.GetThumb(path, sha)
 	if err != nil {
 		return err
 	}
 
-	return c.File(fmt.Sprintf("%s/sprite.vtt", out))
+	return c.File(vtt)
 }
 
 type Handler struct {
 	transcoder *src.Transcoder
+	metadata   src.MetadataService
 }
 
 func main() {
diff --git a/transcoder/src/metadata.go b/transcoder/src/metadata.go
index 22c25a09..77c12687 100644
--- a/transcoder/src/metadata.go
+++ b/transcoder/src/metadata.go
@@ -5,11 +5,25 @@ import (
 )
 
 type MetadataService struct {
-	database *sqlx.DB
-	lock     *RunLock[string, *MediaInfo]
+	database  *sqlx.DB
+	lock      *RunLock[string, *MediaInfo]
+	thumbLock *RunLock[string, interface{}]
 }
 
 func (s MetadataService) GetMetadata(path string, sha string) (*MediaInfo, error) {
+	ret, err := s.getMetadata(path, sha)
+	if err != nil {
+		return nil, err
+	}
+
+	if ret.Versions.Thumbs < ThumbsVersion {
+		go s.ExtractThumbs(path, sha)
+	}
+
+	return ret, nil
+}
+
+func (s MetadataService) getMetadata(path string, sha string) (*MediaInfo, error) {
 	var ret MediaInfo
 	rows, err := s.database.Queryx(`
 		select * from info as i where i.sha=$1;
diff --git a/transcoder/src/thumbnails.go b/transcoder/src/thumbnails.go
index fde155b9..2d6cf5d5 100644
--- a/transcoder/src/thumbnails.go
+++ b/transcoder/src/thumbnails.go
@@ -8,6 +8,7 @@ import (
 	"log"
 	"math"
 	"os"
+	"path/filepath"
 	"sync"
 
 	"github.com/disintegration/imaging"
@@ -28,32 +29,60 @@ type Thumbnail struct {
 
 var thumbnails = NewCMap[string, *Thumbnail]()
 
-func ExtractThumbnail(path string, sha string) (string, error) {
-	ret, _ := thumbnails.GetOrCreate(sha, func() *Thumbnail {
-		ret := &Thumbnail{
-			path: fmt.Sprintf("%s/%s", Settings.Metadata, sha),
-		}
-		ret.ready.Add(1)
-		go func() {
-			extractThumbnail(path, ret.path)
-			ret.ready.Done()
-		}()
-		return ret
-	})
-	ret.ready.Wait()
-	return ret.path, nil
+const ThumbsVersion = 1
+
+func getThumbGlob(sha string) string {
+	return fmt.Sprintf("%s/%s/thumbs-v*.*", Settings.Metadata, sha)
 }
 
-func extractThumbnail(path string, out string) error {
-	defer printExecTime("extracting thumbnails for %s", path)()
-	os.MkdirAll(out, 0o755)
-	sprite_path := fmt.Sprintf("%s/sprite.png", out)
-	vtt_path := fmt.Sprintf("%s/sprite.vtt", out)
+func getThumbPath(sha string) string {
+	return fmt.Sprintf("%s/%s/thumbs-v%d.png", Settings.Metadata, sha, ThumbsVersion)
+}
+
+func getThumbVttPath(sha string) string {
+	return fmt.Sprintf("%s/%s/thumbs-v%d.vtt", Settings.Metadata, sha, ThumbsVersion)
+}
+
+func (s MetadataService) GetThumb(path string, sha string) (string, string, error) {
+	sprite_path := getThumbPath(sha)
+	vtt_path := getThumbVttPath(sha)
 
 	if _, err := os.Stat(sprite_path); err == nil {
-		return nil
+		return sprite_path, vtt_path, nil
 	}
 
+	_, err := s.ExtractThumbs(path, sha)
+	if err != nil {
+		return "", "", err
+	}
+	return sprite_path, vtt_path, nil
+}
+
+func (s MetadataService) ExtractThumbs(path string, sha string) (interface{}, error) {
+	get_running, set := s.thumbLock.Start(sha)
+	if get_running != nil {
+		return get_running()
+	}
+
+	err := extractThumbnail(path, sha)
+	if err != nil {
+		return set(nil, err)
+	}
+	_, err = s.database.NamedExec(
+		`update info set ver_thumbs = :version where sha = :sha`,
+		map[string]interface{}{
+			"sha":     sha,
+			"version": ThumbsVersion,
+		},
+	)
+	return set(nil, err)
+}
+
+func extractThumbnail(path string, sha string) error {
+	defer printExecTime("extracting thumbnails for %s", path)()
+
+	os.MkdirAll(fmt.Sprintf("%s/%s", Settings.Metadata), 0o755)
+
 	gen, err := screengen.NewGenerator(path)
 	if err != nil {
 		log.Printf("Error reading video file: %v", err)
@@ -102,7 +131,7 @@ func extractThumbnail(path string, out string) error {
 			tsToVttTime(timestamps),
 			tsToVttTime(ts),
 			Settings.RoutePrefix,
-			base64.StdEncoding.EncodeToString([]byte(path)),
+			base64.RawURLEncoding.EncodeToString([]byte(path)),
 			x,
 			y,
 			width,
@@ -110,11 +139,20 @@ func extractThumbnail(path string, out string) error {
 		)
 	}
 
-	err = os.WriteFile(vtt_path, []byte(vtt), 0o644)
+	// Cleanup old versions of thumbnails
+	files, err := filepath.Glob(getThumbGlob(sha))
+	if err == nil {
+		for _, f := range files {
+			// ignore errors
+			os.Remove(f)
+		}
+	}
+
+	err = os.WriteFile(getThumbVttPath(sha), []byte(vtt), 0o644)
 	if err != nil {
 		return err
 	}
-	err = imaging.Save(sprite, sprite_path)
+	err = imaging.Save(sprite, getThumbPath(sha))
 	if err != nil {
 		return err
 	}