diff --git a/src/api/media_api.rs b/src/api/media_api.rs
index 9d30dba..1a4ff99 100644
--- a/src/api/media_api.rs
+++ b/src/api/media_api.rs
@@ -408,7 +408,7 @@ async fn trace_video(
             if let Some((x, y, w, h)) = bbox_per_frame.get(&(*tid, *fn_)) {
                 let n = *fn_ as i64 - frame_offset;
                 parts.push(format!(
-                    "drawbox=x={}:y={}:w={}:h={}:color=green@0.7:thickness=2:enable='between(n,{},{})'",
+                    "drawbox=x={}:y={}:w={}:h={}:color=green@0.5:thickness=2:enable='between(n,{},{})'",
                     x, y, w, h, n, n
                 ));
                 parts.push(format!(