diff --git a/entity/ffmpeg.py b/entity/ffmpeg.py
index 3e864a0..7471be4 100644
--- a/entity/ffmpeg.py
+++ b/entity/ffmpeg.py
@@ -271,9 +271,10 @@ class FfmpegTask(object):
                     if param == '':
                         param = "1"
                     if param != "1":
-                        # 视频变速
+                        # 视频变速：通过改变帧率实现，避免PTS冲突
                         effect_index += 1
-                        filter_args.append(f"{video_output_str}setpts={param}*PTS[v_eff{effect_index}]")
+                        new_fps = self.frame_rate / float(param)
+                        filter_args.append(f"{video_output_str}fps={new_fps}[v_eff{effect_index}]")
                         video_output_str = f"[v_eff{effect_index}]"
                 elif effect.startswith("zoom:"):
                     param = effect.split(":", 2)[1]