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 on sites like YouTube, Metacafe, and more. It supports MPEG-4 Part 10 (H.264) video codec and AAC sound.
RealPlayer, Apple QuicTime Player MPLayer VLC Media Player
WAV, sometimes called WAV, is an audio container format developed by IBM and Microsoft and comes with a .wav filename extension. Unlike popular formats like MP3 and MP4, WAV isn’t a lossy format, so it’s bigger and less popular. WAV files can be opened on various OS platforms via software like Windows Media Player, MPlayer, VLC Media Player, and more.