diff --git a/app/providers/volcengine/capabilities.py b/app/providers/volcengine/capabilities.py
index e56cc3b..b406d0e 100644
--- a/app/providers/volcengine/capabilities.py
+++ b/app/providers/volcengine/capabilities.py
@@ -102,13 +102,16 @@ def validate(
             f"可选：{sorted(limits.resolutions)}"
         )
 
-    if duration_sec is not None and duration_sec != AUTO_DURATION:
-        if not limits.min_duration_sec <= duration_sec <= limits.max_duration_sec:
-            raise ValueError(
-                f"模型 {model} 的时长需在 "
-                f"[{limits.min_duration_sec}, {limits.max_duration_sec}] 秒内"
-                f"（或 {AUTO_DURATION} 表示由模型自选），当前 {duration_sec}"
-            )
+    if (
+        duration_sec is not None
+        and duration_sec != AUTO_DURATION
+        and not limits.min_duration_sec <= duration_sec <= limits.max_duration_sec
+    ):
+        raise ValueError(
+            f"模型 {model} 的时长需在 "
+            f"[{limits.min_duration_sec}, {limits.max_duration_sec}] 秒内"
+            f"（或 {AUTO_DURATION} 表示由模型自选），当前 {duration_sec}"
+        )
 
     if (
         has_first_frame