diff --git a/backend/media/service.go b/backend/media/service.go
index b847724..a770afc 100644
--- a/backend/media/service.go
+++ b/backend/media/service.go
@@ -524,7 +524,7 @@ func (r *ModuloBufReader) Read(p []byte) (int, error) {
 	rem := nr % r.modSize
 	if rem != 0 {
 		// err is always nil
-		_, _ = r.buf.Write(p[nr-rem:])
+		_, _ = r.buf.Write(p[nr-rem : nr])
 	}
 
 	return nr - rem, err