feat(video): 添加原始变速效果支持

- 在常量定义中新增 ospeed 效果类型用于兼容旧模板
- 在任务域中实现 get_ospeed_params 方法解析变速参数
- 修改视频渲染处理器合并 speed 与 ospeed 效果计算
- 更新时长计算逻辑以正确处理 ospeed 变速影响
- 新增 ospeed 参数验证和边界值处理机制
- 添加完整的 ospeed 效果单元测试覆盖各种场景

handlers/render_video.py

@@ -502,12 +502,20 @@ class RenderSegmentVideoHandler(BaseHandler):
             # 去掉末尾的逗号，作为第一个滤镜
             filters.append(hwaccel_prefix.rstrip(','))
 
-        # 1. 变速处理
+        # 1. 变速处理（合并 RenderSpec.speed 与 ospeed 效果）
         speed = float(render_spec.speed) if render_spec.speed else 1.0
-        if speed != 1.0 and speed > 0:
-            # setpts 公式：PTS / speed
-            pts_factor = 1.0 / speed
-            filters.append(f"setpts={pts_factor}*PTS")
+        if speed <= 0:
+            speed = 1.0
+
+        ospeed_factor = 1.0
+        for effect in effects:
+            if effect.effect_type == 'ospeed':
+                ospeed_factor = effect.get_ospeed_params()
+                break
+
+        combined_pts_factor = (1.0 / speed) * ospeed_factor
+        if combined_pts_factor != 1.0:
+            filters.append(f"setpts={combined_pts_factor}*PTS")
 
         # 2. LUT 调色
         if lut_file:
@@ -569,15 +577,13 @@ class RenderSegmentVideoHandler(BaseHandler):
         # 计算是否需要额外的尾部冻结（源视频时长不足）
         extra_tail_freeze_sec = 0.0
         if source_duration_sec is not None:
-            speed = float(render_spec.speed) if render_spec.speed else 1.0
-            if speed > 0:
-                # 计算变速后的有效时长
-                effective_duration_sec = source_duration_sec / speed
-                required_duration_sec = duration_ms / 1000.0
+            # 使用已计算的 combined_pts_factor
+            effective_duration_sec = source_duration_sec * combined_pts_factor
+            required_duration_sec = duration_ms / 1000.0
 
-                # 如果源视频时长不足，需要冻结最后一帧来补足
-                if effective_duration_sec < required_duration_sec:
-                    extra_tail_freeze_sec = required_duration_sec - effective_duration_sec
+            # 如果源视频时长不足，需要冻结最后一帧来补足
+            if effective_duration_sec < required_duration_sec:
+                extra_tail_freeze_sec = required_duration_sec - effective_duration_sec
 
         if overlap_head_ms > 0:
             # 头部冻结：将第一帧冻结指定时长
@@ -732,14 +738,20 @@ class RenderSegmentVideoHandler(BaseHandler):
         extra_tail_freeze_sec = 0.0
         if source_duration_sec is not None and render_spec is not None and duration_ms > 0:
             speed = float(render_spec.speed) if render_spec.speed else 1.0
-            if speed > 0:
-                # 计算变速后的有效时长
-                effective_duration_sec = source_duration_sec / speed
-                required_duration_sec = duration_ms / 1000.0
+            if speed <= 0:
+                speed = 1.0
+            ospeed_factor = 1.0
+            for effect in effects:
+                if effect.effect_type == 'ospeed':
+                    ospeed_factor = effect.get_ospeed_params()
+                    break
+            combined_pts_factor = (1.0 / speed) * ospeed_factor
+            effective_duration_sec = source_duration_sec * combined_pts_factor
+            required_duration_sec = duration_ms / 1000.0
 
-                # 如果源视频时长不足，需要冻结最后一帧来补足
-                if effective_duration_sec < required_duration_sec:
-                    extra_tail_freeze_sec = required_duration_sec - effective_duration_sec
+            # 如果源视频时长不足，需要冻结最后一帧来补足
+            if effective_duration_sec < required_duration_sec:
+                extra_tail_freeze_sec = required_duration_sec - effective_duration_sec
 
         if overlap_head_ms > 0:
             head_duration_sec = overlap_head_ms / 1000.0