diff --git a/nodes/frame_extract.py b/nodes/frame_extract.py
index 4165ac6..5c3e526 100644
--- a/nodes/frame_extract.py
+++ b/nodes/frame_extract.py
@@ -21,8 +21,8 @@ from wov_sdk.models import InvokeRequest, InvokeResponse
 
 logger = get_logger("frame-extract")
 
-# 默认裁切：画面底部 18% 区域（常见字幕位置）。
-DEFAULT_CROP = [0.0, 0.82, 1.0, 0.18]
+# 默认裁切：画面底部 1/4 区域（字幕区，字幕很少出现在画面上半部分）。
+DEFAULT_CROP = [0.0, 0.75, 1.0, 0.25]
 
 
 def _parse_crop(raw) -> list[float] | None:
diff --git a/tests/test_apps_api.py b/tests/test_apps_api.py
index 7775216..ab978b2 100644
--- a/tests/test_apps_api.py
+++ b/tests/test_apps_api.py
@@ -293,12 +293,12 @@ def test_create_run_with_param_overrides() -> None:
         uploaded = client.post(
             f"/api/apps/{workflow_id}/runs",
             files={"file": ("sample.txt", b"x", "text/plain")},
-            data={"params": '{"step": {"crop": [0, 0.82, 1, 0.18]}}'},
+            data={"params": '{"step": {"crop": [0, 0.75, 1, 0.25]}}'},
         )
         assert uploaded.status_code == 200
         run_id = uploaded.json()["id"]
         run = client.get(f"/api/runs/{run_id}").json()
-        assert run["param_overrides"] == {"step": {"crop": [0, 0.82, 1, 0.18]}}
+        assert run["param_overrides"] == {"step": {"crop": [0, 0.75, 1, 0.25]}}
         # 非法 JSON 返回 422。
         bad = client.post(
             f"/api/apps/{workflow_id}/runs",
diff --git a/workflows/ocr-subtitle.json b/workflows/ocr-subtitle.json
index 2d6e68c..2d9e863 100644
--- a/workflows/ocr-subtitle.json
+++ b/workflows/ocr-subtitle.json
@@ -14,9 +14,9 @@
           "interval_seconds": 0.5,
           "crop": [
             0,
-            0.82,
+            0.75,
             1,
-            0.18
+            0.25
           ]
         },
         "inputs": {