优化首帧功能，如果没传入首帧，则提取首帧。

wechat_ipad/client/message.py

@@ -1,6 +1,7 @@
 import asyncio
 import base64
 import os
+import time
 from asyncio import Future
 from asyncio import Queue, sleep
 from io import BytesIO
@@ -14,6 +15,7 @@ from pymediainfo import MediaInfo
 import pysilk
 from pydub import AudioSegment
 
+from utils.video_utils import _get_first_frame
 from wechat_ipad import UserLoggedOut
 from wechat_ipad.client.base import WechatAPIClientBase
 
@@ -214,8 +216,7 @@ class MessageMixin(WechatAPIClientBase):
                     ValueError: 视频或图片参数都为空或都不为空时
                     根据error_handler处理错误
                 """
-        if not image:
-            image = Path(os.path.join(Path(__file__).resolve().parent, "fallback.png"))
+
         # get video base64 and duration
         if isinstance(video, str):
             vid_base64 = video
@@ -235,6 +236,9 @@ class MessageMixin(WechatAPIClientBase):
             file_len = len(video_bytes)
             vid_base64 = base64.b64encode(video_bytes).decode()
             media_info = MediaInfo.parse(video_path)
+            first_frame = _get_first_frame(video_path, f"dify_frame_{int(time.time())}.jpg")
+            if first_frame:
+                image = first_frame
         else:
             raise ValueError("video should be str, bytes, or path")
             # 获取视频时长
@@ -246,7 +250,8 @@ class MessageMixin(WechatAPIClientBase):
         if duration is None:
             duration = 1
             self.logging.error(f"无法从视频文件获取时长: {video}")
-
+        if not image:
+            image = Path(os.path.join(Path(__file__).resolve().parent, "fallback.png"))
         # get image base64
         if isinstance(image, str):
             image_base64 = image