diff --git a/yt_dlp/postprocessor/ffmpeg.py b/yt_dlp/postprocessor/ffmpeg.py
index 87db9bd3e..dfbd77a39 100644
--- a/yt_dlp/postprocessor/ffmpeg.py
+++ b/yt_dlp/postprocessor/ffmpeg.py
@@ -8,8 +8,6 @@
 import subprocess
 import time
 
-from yt_dlp.utils._utils import strftime_or_none
-
 from .common import PostProcessor
 from ..compat import imghdr
 from ..utils import (
@@ -30,6 +28,7 @@
     prepend_extension,
     replace_extension,
     shell_quote,
+    strftime_or_none,
     traverse_obj,
     variadic,
     write_json_file,
@@ -753,7 +752,7 @@ def add(meta_list, info_list=None, convert=str):
         # https://kodi.wiki/view/Video_file_tagging
 
         add('title', ('track', 'title'))
-        add('date', ('release_date', 'upload_date'), lambda date: strftime_or_none(date, '%Y-%m-%d'))
+        add('date', ('release_date', 'upload_date'), convert=strftime_or_none(date_format='%Y-%m-%d'))
         add(('description', 'synopsis'), 'description')
         add(('purl', 'comment'), 'webpage_url')
         add('track', 'track_number')
diff --git a/yt_dlp/utils/_utils.py b/yt_dlp/utils/_utils.py
index a71a381e5..254eca39d 100644
--- a/yt_dlp/utils/_utils.py
+++ b/yt_dlp/utils/_utils.py
@@ -2046,6 +2046,7 @@ def url_or_none(url):
     return url if re.match(r'(?:(?:https?|rt(?:m(?:pt?[es]?|fp)|sp[su]?)|mms|ftps?):)?//', url) else None
 
 
+@partial_application
 def strftime_or_none(timestamp, date_format='%Y%m%d', default=None):
     datetime_object = None
     try: