diff --git a/apps/worker/video_processing/pip_engine.py b/apps/worker/video_processing/pip_engine.py
index 762fee4d6..fe5e4a799 100755
--- a/apps/worker/video_processing/pip_engine.py
+++ b/apps/worker/video_processing/pip_engine.py
@@ -124,7 +124,9 @@ class PiPEngine:
         if layer.border_width > 0:
             bw = layer.border_width
             color = layer.border_color
-            filters.append(f"pad={pip_width + 2*bw}:{pip_height + 2*bw}:{bw}:{bw}:{color}")
+            filters.append(
+                f"pad={pip_width + 2*bw}:{pip_height + 2*bw}:{bw}:{bw}:{color}"
+            )
 
         # Step 4: 透明度
         if layer.opacity < 1.0:
@@ -165,7 +167,9 @@ class PiPEngine:
             # 淡出需要知道总时长，这里用表达式
             if layer.duration > 0:
                 start_fade = layer.duration - anim_dur
-                filters.append(f"fade=t=out:st={max(0, start_fade)}:d={anim_dur}:alpha=1")
+                filters.append(
+                    f"fade=t=out:st={max(0, start_fade)}:d={anim_dur}:alpha=1"
+                )
 
         return filters
 
@@ -274,7 +278,9 @@ class PiPEngine:
             base_x, base_y = self._parse_position(layer, pip_w, pip_h)
 
             # 构建overlay表达式（支持滑动动画）
-            x_expr, y_expr = self._build_overlay_expr(layer, base_x, base_y, pip_w, pip_h)
+            x_expr, y_expr = self._build_overlay_expr(
+                layer, base_x, base_y, pip_w, pip_h
+            )
 
             # 时间控制（enable表达式）
             enable_expr = ""
@@ -291,7 +297,9 @@ class PiPEngine:
 
             # overlay 滤镜
             overlay_filter = (
-                f"[{current_label}][{pre_label}]" f"overlay={x_expr}:{y_expr}{enable_expr}" f"[{combined_label}]"
+                f"[{current_label}][{pre_label}]"
+                f"overlay={x_expr}:{y_expr}{enable_expr}"
+                f"[{combined_label}]"
             )
             filter_parts.append(overlay_filter)
 
@@ -338,7 +346,9 @@ class PiPEngine:
                     validate_url_safety(layer.source, purpose="pip_source")
                     logger.info("PiP URL 安全校验通过: %s", layer.source[:80])
                 except UrlSecurityError as e:
-                    logger.warning("PiP URL 安全校验失败: %s (error=%s)", layer.source[:80], e)
+                    logger.warning(
+                        "PiP URL 安全校验失败: %s (error=%s)", layer.source[:80], e
+                    )
                     return None
                 # 暂时不支持直接URL下载，返回None表示降级跳过
                 return None