No. Codecs are registered standards like avc1, hev1, mp4v. File extensions are .mp4, .m4v, .m4a. adn564 appears to be an arbitrary identifier.
Digital Signature Verification:
In some systems (surveillance, medical imaging, industrial inspection), strings like adn564mp4 could be:
In that case, verification involves checking the file against a database entry or manifest.
Hackers can embed exploits in MP4 files (e.g., heap spray attacks via malformed stts boxes). A “verified” label on a pirated or untrusted site is no guarantee of safety.
Rule of thumb: Only trust MP4 files from verified sources (official websites, known content creators with digital signatures). Never trust a generic “i adn564mp4 verified” badge.