1、修改前台登陆样式背景可使用视频

2、增加后台配置前台背景样式

video-gen-api/app/api/v1/admin.py

@@ -2281,6 +2281,62 @@ async def upload_logo(
     return {"url": url}
 
 
+@router.post("/upload-login-video")
+async def upload_login_video(
+    file: UploadFile = File(...),
+    admin: User = Depends(get_admin_user),
+    db: AsyncSession = Depends(get_db),
+):
+    """上传登录页背景视频，保存 URL 到 system config login_bg_video。"""
+    from app.config import settings
+
+    if not file.filename:
+        raise HTTPException(status_code=400, detail="请选择文件")
+
+    allowed_extensions = ('.mp4', '.webm', '.mov')
+    if not file.filename.lower().endswith(allowed_extensions):
+        raise HTTPException(status_code=400, detail="仅支持 MP4、WebM、MOV 视频格式")
+
+    content = await file.read()
+    if len(content) > 50 * 1024 * 1024:
+        raise HTTPException(status_code=400, detail="文件大小不能超过50MB")
+
+    ext = os.path.splitext(file.filename)[1].lower()
+    safe_name = f"login_bg_{generate_id()}{ext}"
+    file_path = os.path.join(settings.UPLOAD_LOCAL_PATH, safe_name)
+    with open(file_path, "wb") as f:
+        f.write(content)
+
+    url = f"/uploads/{safe_name}"
+
+    result = await db.execute(
+        select(SystemConfig).where(SystemConfig.key == "login_bg_video").limit(1)
+    )
+    config = result.scalar_one_or_none()
+    if config:
+        config.value = url
+    else:
+        db.add(SystemConfig(
+            id=generate_id(),
+            key="login_bg_video",
+            value=url,
+            description="登录页背景视频",
+        ))
+    await db.flush()
+    await log_operation(
+        db,
+        admin.id,
+        admin.username,
+        f"上传登录背景视频: {file.filename}",
+        "POST",
+        "/admin/upload-login-video",
+        detail=json.dumps({"filename": file.filename, "url": url}, ensure_ascii=False),
+    )
+    await db.commit()
+
+    return {"url": url}
+
+
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