DAT file is a file format written to save sounds, midi, wave, pallets, images, and levels. In short, this file format contains vital information for specific software, and the data is usually in either binary or plain text. In rare cases, DAT files may include a video file. DAT files are opened using text editors like Notepad++ and TextEdit.
MKV is a container format for holding multiple audio, video, picture, and text data such as subtitle tracks. It is similar to other common containers like MP4 and AVI, although MKV is open in the specification. For video contents, MKV uses a .mkv filename extension, .mka for audios, and .mks for subtitles.
MPC-HC, KMPlayer VLC Media Player MKV File Player MPV