feat: 视频调速引擎（快进/慢放） (#294)

apps/api/app/api/routes/edit_plans.py

@@ -211,6 +211,7 @@ class _PlanClipItem(BaseModel):
     duration: float
     transition_effect: str
     transition_duration: float
+    playback_speed: float = 1.0
     status: str
     config: Optional[dict[str, Any]] = None
     created_at: datetime

apps/api/app/services/edit_plan_service.py

@@ -282,6 +282,7 @@ class EditPlanService:
         duration: float = 0.0,
         transition_effect: str = "cut",
         transition_duration: float = 0.0,
+        playback_speed: float = 1.0,
         config: Optional[dict[str, Any]] = None,
     ) -> EditPlanClip:
         """创建片段
@@ -303,6 +304,7 @@ class EditPlanService:
             duration=duration,
             transition_effect=transition_effect,
             transition_duration=transition_duration,
+            playback_speed=playback_speed,
             config=config,
         )
         created = self._clip_repo.create(clip)
@@ -327,6 +329,7 @@ class EditPlanService:
         duration: Optional[float] = None,
         transition_effect: Optional[str] = None,
         transition_duration: Optional[float] = None,
+        playback_speed: Optional[float] = None,
         config: Optional[dict[str, Any]] = None,
     ) -> EditPlanClip:
         """更新片段
@@ -336,6 +339,15 @@ class EditPlanService:
         """
         existing = self.get_clip_or_raise(clip_id)
 
+        # 速度边界钳制
+        if playback_speed is not None:
+            if playback_speed <= 0:
+                playback_speed = 1.0
+            elif playback_speed < 0.25:
+                playback_speed = 0.25
+            elif playback_speed > 4.0:
+                playback_speed = 4.0
+
         updated = EditPlanClip(
             id=existing.id,
             plan_id=existing.plan_id,
@@ -352,6 +364,7 @@ class EditPlanService:
             transition_duration=(
                 transition_duration if transition_duration is not None else existing.transition_duration
             ),
+            playback_speed=playback_speed if playback_speed is not None else existing.playback_speed,
             status=existing.status,
             config=config if config is not None else existing.config,
             created_at=existing.created_at,