CAF (Core Audio Format) is a free audio container format developed by Apple and works on macOS 10.4 or later. It can also be opened on macOS 10.3 using QuickTime 7. Apart from audio, CAF can also hold multiple metadata such as file name, album name, composer, and more. It comes with a filename extension of .caf.
Apple QuickTime Player Soundtrack Pro Logic Studio
FLV (Flash Video) is a video container format developed by Adobe Systems and comes with a .flv filename format. FLV is primarily used to stream audio, video, and text data such as subtitles. It supports MPEG-4 Part 10 (H.264) video codec and AAC sound.
RealPlayer, Apple QuicTime Player
VLC Media Player