调整后台文字模型请求发送图片或者视频的方式base64，而不是现在的链接形式，增加后台配置

video-gen-api/app/services/generation/prompt_service.py

@@ -36,7 +36,9 @@ def _load_refs(record: ChatGenerationTask) -> list[dict]:
         return []
 
 
-def _build_user_content(record: ChatGenerationTask) -> list[dict[str, Any]]:
+async def _build_user_content(record: ChatGenerationTask, db: AsyncSession | None = None) -> list[dict[str, Any]]:
+    from app.utils.media import media_to_base64
+
     if record.gen_type == "image":
         params = f"图片参数：分辨率档位={record.image_size or '2K'}，比例={record.image_proportion or '1:1'}，像素={record.image_px or '2048x2048'}"
     else:
@@ -54,7 +56,15 @@ def _build_user_content(record: ChatGenerationTask) -> list[dict[str, Any]]:
         ref_url = ref.get("url") or ""
         if not ref_url:
             continue
-        url = _absolute_url(ref_url)
+        if db and await get_llm_media_as_base64(db):
+            if ref_type == "image":
+                url = await media_to_base64(ref_url, "image/png")
+            elif ref_type == "video":
+                url = await media_to_base64(ref_url, "video/mp4")
+            else:
+                continue
+        else:
+            url = _absolute_url(ref_url)
         if ref_type == "image":
             parts.append({"type": "image_url", "image_url": {"url": url}})
         elif ref_type == "video":
@@ -94,7 +104,7 @@ async def build_prompt_with_chatapi(db: AsyncSession, record: ChatGenerationTask
         "model": config.model_name,
         "messages": [
             {"role": "system", "content": system_prompt},
-            {"role": "user", "content": _build_user_content(record)},
+            {"role": "user", "content": await _build_user_content(record, db)},
         ],
         "max_tokens": config.max_tokens,
         "temperature": config.temperature,