: Filenames ending in .mp4 or .mkv that are actually .exe or other executable formats are a common way to spread viruses.

: The video compression standards (codecs) used to make the file size manageable while maintaining quality.

: This indicates the file contains multiple audio tracks, likely the original English audio and a Hindi dubbed version that you can switch between in your media player.

: These are "containers." While the name lists both, it indicates the file is likely an MKV (which supports multiple audio tracks) renamed or converted for compatibility.