From 4f6ac9c8aa002ee97573bdb54e4cdee97c25aa81 Mon Sep 17 00:00:00 2001
From: xiaoxia <xiaoxia@xiaoxiajianji.com>
Date: Mon, 24 Aug 2026 00:49:03 +0800
Subject: [PATCH] fix: add speed_cfg.clamp() + comment explaining multi-stage
 atempo in pass-through

SpeedEngine.build_audio_filter already handles out-of-range speeds via
multi-stage atempo chaining (e.g. 0.25x -> atempo=0.5,atempo=0.5).
Add explicit clamp() and comment to make this clear.
---
 apps/worker/video_processing/unified_render_service.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/apps/worker/video_processing/unified_render_service.py b/apps/worker/video_processing/unified_render_service.py
index 46e5097ed..cc15f1c6c 100755
--- a/apps/worker/video_processing/unified_render_service.py
+++ b/apps/worker/video_processing/unified_render_service.py
@@ -1311,12 +1311,15 @@ class UnifiedRenderService:
                 af_parts.append(f"volume={clip_volume:.4f}")
 
             # 音频调速（与视频setpts对应，保持音画同步）
+            # SpeedEngine.build_audio_filter 内部已实现多级 atempo 串联，
+            # 自动处理超出 [0.5, 2.0] 范围的速度（如 0.25x → atempo=0.5,atempo=0.5）。
             speed = UnifiedRenderService._clip_speed(clip)
             if abs(speed - 1.0) >= 1e-6:
                 try:
                     from video_processing.speed_engine import SpeedConfig, SpeedEngine
 
                     speed_cfg = SpeedConfig(speed=speed)
+                    speed_cfg.clamp()
                     speed_engine = SpeedEngine()
                     af_parts.append(speed_engine.build_audio_filter(speed_cfg))
                 except Exception as e: