ERROR: Unsupported URL: https://mediasetinfinity.mediaset.it

You need to provide the URL of a page that plays a video and in this case, because mediaset has form, show that it plays in your browser session with DRM disabled.

For anyone who wants to work on this (subject to the above):

• I looked at https://mediasetinfinity.mediaset.it/video/tg4/edizione-ore-1900-dell-1-agosto_F312336801042601
• there is a full json+ld block whose @id seems to be the URL of a embedded player: the JS loaded from this includes references to Widevine, PlayReady and FairPlay, supporting my point above
• the page has a gigantic window.INITIAL_STATE JS string that is a base64-encode of compressed (presumably) JSON
• JS atob() decodes the string to some binary stuff but Python's base64.decode() seems to need some tweaking of the trailing/padding end of the string, eg strippingA== and appending ===
• the compressed data doesn't decode with Python's zlib (includes gzip) nor bzip2
• the site JS includes a function decompressFromBase64() that calls _decompress(), but there is some external linkage in these.