diff --git a/yt_dlp/extractor/ard.py b/yt_dlp/extractor/ard.py
index 4d90be7140..a9cd13a058 100644
--- a/yt_dlp/extractor/ard.py
+++ b/yt_dlp/extractor/ard.py
@@ -290,7 +290,7 @@ class ARDMediathekIE(ARDMediathekBaseIE):
 
 
 class ARDIE(InfoExtractor):
-    _VALID_URL = r'(?P<mainurl>https?://(?:www\.)?daserste\.de/[^?#]+/videos(?:extern)?/(?P<display_id>[^/?#]+)-(?:video-?)?(?P<id>[0-9]+))\.html'
+    _VALID_URL = r'(?P<mainurl>https?://(?:www\.)?daserste\.de/[^?#]+/videos(?:extern)?/(?P<display_id>[^/?#]+)-?(?:video-?)?(?P<id>[0-9]+))\.html'
     _TESTS = [{
         # available till 7.01.2022
         'url': 'https://www.daserste.de/information/talk/maischberger/videos/maischberger-die-woche-video100.html',
@@ -307,6 +307,9 @@ class ARDIE(InfoExtractor):
     }, {
         'url': 'https://www.daserste.de/information/reportage-dokumentation/erlebnis-erde/videosextern/woelfe-und-herdenschutzhunde-ungleiche-brueder-102.html',
         'only_matching': True,
+    }, {
+        'url': 'https://www.daserste.de/unterhaltung/serie/in-aller-freundschaft-die-jungen-aerzte/videos/diversity-tag-sanam-afrashteh100.html',
+        'only_matching': True,
     }, {
         'url': 'http://www.daserste.de/information/reportage-dokumentation/dokus/videos/die-story-im-ersten-mission-unter-falscher-flagge-100.html',
         'only_matching': True,
diff --git a/yt_dlp/postprocessor/embedthumbnail.py b/yt_dlp/postprocessor/embedthumbnail.py
index 9923ef6a4f..2d736a31a3 100644
--- a/yt_dlp/postprocessor/embedthumbnail.py
+++ b/yt_dlp/postprocessor/embedthumbnail.py
@@ -128,7 +128,7 @@ class EmbedThumbnailPP(FFmpegPostProcessor):
                     meta = MP4(filename)
                     # NOTE: the 'covr' atom is a non-standard MPEG-4 atom,
                     # Apple iTunes 'M4A' files include the 'moov.udta.meta.ilst' atom.
-                    f = {'jpeg': MP4Cover.FORMAT_JPEG, 'png':MP4Cover.FORMAT_PNG}[imghdr.what(thumbnail_filename)]
+                    f = {'jpeg': MP4Cover.FORMAT_JPEG, 'png': MP4Cover.FORMAT_PNG}[imghdr.what(thumbnail_filename)]
                     with open(thumbnail_filename, 'rb') as thumbfile:
                         thumb_data = thumbfile.read()
                     meta.tags['covr'] = [MP4Cover(data=thumb_data, imageformat=f)]