diff --git a/apps/worker/video_processing/speed_engine.py b/apps/worker/video_processing/speed_engine.py
index 5c2d92f4d..82100e284 100755
--- a/apps/worker/video_processing/speed_engine.py
+++ b/apps/worker/video_processing/speed_engine.py
@@ -15,6 +15,8 @@ from __future__ import annotations
 
 from packages.domain.speed_config import (
     DEFAULT_SPEED,
+    MAX_SPEED,
+    MIN_SPEED,
     SpeedConfig,
     _split_atempo_stages,
 )
@@ -68,3 +70,35 @@ class SpeedEngine:
     ) -> float:
         """从 clip config 中解析 playback_speed，0 或缺失则使用全局速度."""
         return _resolve_clip_speed_base(clip_config, global_speed)
+
+
+# ── 向后兼容：模块级函数（重构前的 API） ─────────────────────────
+def build_video_filter(config):
+    """向后兼容：模块级 build_video_filter."""
+    return _build_video_filter_base(config)
+
+
+def build_audio_filter(config):
+    """向后兼容：模块级 build_audio_filter."""
+    return _build_audio_filter_base(config)
+
+
+def adjust_duration(original_duration, config):
+    """向后兼容：模块级 adjust_duration."""
+    return _adjust_duration_base(original_duration, config)
+
+
+def resolve_clip_speed(clip_config, global_speed=DEFAULT_SPEED):
+    """向后兼容：模块级 resolve_clip_speed."""
+    return _resolve_clip_speed_base(clip_config, global_speed)
+
+
+def build_clip_speed_filter(speed, pitch_correct=True):
+    """向后兼容：模块级 build_clip_speed_filter."""
+    config = SpeedConfig(speed=speed, pitch_correct=pitch_correct)
+    config.clamp()
+    return (
+        build_video_filter(config),
+        build_audio_filter(config),
+        config,
+    )