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
AIiF (Apple Interchange File Format/Audio Interchange File) is a sound format used on Mac OS X. It comes with a .aiif filename extension and .aif when used on Windows. An AIF file features raw sound data like sample rate, bit depth, and channel (mono/stereo). This file format is also accepted on most CD writers.
File Viewer Plus Apple iTunes QuickTime Player Adobe Audition CC 2019