1 files changed, 16 insertions, 0 deletions
diff --git a/yt_dlp/compat/imghdr.py b/yt_dlp/compat/imghdr.py
new file mode 100644
index 0000000..5d64ab0
--- /dev/null
+++ b/yt_dlp/compat/imghdr.py
@@ -0,0 +1,16 @@
+tests = {
+    'webp': lambda h: h[0:4] == b'RIFF' and h[8:] == b'WEBP',
+    'png': lambda h: h[:8] == b'\211PNG\r\n\032\n',
+    'jpeg': lambda h: h[6:10] in (b'JFIF', b'Exif'),
+    'gif': lambda h: h[:6] in (b'GIF87a', b'GIF89a'),
+}
+
+
+def what(file=None, h=None):
+    """Detect format of image (Currently supports jpeg, png, webp, gif only)
+    Ref: https://github.com/python/cpython/blob/3.10/Lib/imghdr.py
+    """
+    if h is None:
+        with open(file, 'rb') as f:
+            h = f.read(12)
+    return next((type_ for type_, test in tests.items() if test(h)), None)