diff --git a/test/test_utils.py b/test/test_utils.py
index 3ff1f8b55..e82f551bc 100644
--- a/test/test_utils.py
+++ b/test/test_utils.py
@@ -929,6 +929,11 @@ def test_parse_codecs(self):
             'acodec': 'none',
             'dynamic_range': 'DV',
         })
+        self.assertEqual(parse_codecs('fLaC'), {
+            'vcodec': 'none',
+            'acodec': 'flac',
+            'dynamic_range': None,
+        })
         self.assertEqual(parse_codecs('theora, vorbis'), {
             'vcodec': 'theora',
             'acodec': 'vorbis',
diff --git a/yt_dlp/utils/_utils.py b/yt_dlp/utils/_utils.py
index b582b7d4e..2c23b3ed5 100644
--- a/yt_dlp/utils/_utils.py
+++ b/yt_dlp/utils/_utils.py
@@ -2984,6 +2984,7 @@ def parse_codecs(codecs_str):
         str.strip, codecs_str.strip().strip(',').split(','))))
     vcodec, acodec, scodec, hdr = None, None, None, None
     for full_codec in split_codecs:
+        full_codec = re.sub(r'^([^.]+)', lambda m: m.group(1).lower(), full_codec)
         parts = re.sub(r'0+(?=\d)', '', full_codec).split('.')
         if parts[0] in ('avc1', 'avc2', 'avc3', 'avc4', 'vp9', 'vp8', 'hev1', 'hev2',
                         'h263', 'h264', 'mp4v', 'hvc1', 'av1', 'theora', 'dvh1', 'dvhe'):