MKA is a free Matroska Multimedia Container format that can store multiple audio, video, image, and subtitle tracks. It’s used to save typical multimedia content such as TV shows and movies and comes with a .mkv for video files. When used on audio files, it features a .mka filename extension, .mks for subtitles, and .mk3d for stereoscopic video files.
MP4 (MPEG-4 Part 14) is a video container format based on QuickTime MOV. But unlike MOV, it adds support for other MPEG features. MP4 supports video (MPEG-4 Part 2 and MPEG-4 Part 10/H.264), audio (MP3, AAC, SLS, TTSI, and ALAC), and subtitles (MPEG-4 timed text). It’s this codec combination that gives MP4 its flexibility.
Windows Media Player VLC Media Player, Apple QuickTime Player 5KPLayer