There is only one file type that uses the .JV extension:
Bitmap Brothers Video File
A JV file is a multimedia file used by Z (for MS-DOS) and Z 95 (for Windows 95), a real-time strategy video game developed by Bitmap Brothers. It contains audio and video data and metadata, such as copyright information and the video compression method. JV files are used to save scenes played at various points of gameplay, including when the game first loads and between levels.
You will most likely only encounter a JV multimedia file if you play Z and are exploring the game resource files in the installation directory. Since the game was released back in 1996, JV files are uncommon.
Some examples of video data included in a JV file are the number of frames, the frame rate, and the frame width and height. Some examples of audio data included in a JV file are the audio frequency, sound volume, and audio format.
NOTE: Bitmap Brothers is a British video game developer founded in 1987 that developed various video games in the 1980s and 1990s.
Since the JV file type is uncommon, you will most likely not be able to find a program that can play the video. Instead, you can convert JV files to a more widely supported video format with FFmpeg, then play the converted file with a media player, such as VideoLAN VLC media player or Apple QuickTime Player.
Updated: November 24, 2020