yt_dlp/compat/imghdr.py

   1 tests = {
   2     'webp': lambda h: h[0:4] == b'RIFF' and h[8:] == b'WEBP',
   3     'png': lambda h: h[:8] == b'\211PNG\r\n\032\n',
   4     'jpeg': lambda h: h[6:10] in (b'JFIF', b'Exif'),
   5     'gif': lambda h: h[:6] in (b'GIF87a', b'GIF89a'),
   6 }
   7
   8
   9 def what(file=None, h=None):
  10     """Detect format of image (Currently supports jpeg, png, webp, gif only)
  11     Ref: https://github.com/python/cpython/blob/3.10/Lib/imghdr.py
  12     """
  13     if h is None:
  14         with open(file, 'rb') as f:
  15             h = f.read(12)
  16     return next((type_ for type_, test in tests.items() if test(h)), None)