There is only one file type that uses the .VP5 extension:
On2 VP5 Video File
A VP5 file is a video file that contains video and audio data compressed with the VP5 video codec. It is used to stream video over the Internet at a quality similar to the MPEG-2 standard.
The VP5 format was developed by On2 Technologies in the early-2000s and released in 2002 to improve upon the VP4 codec. VP5 is roughly a 50% improvement over VP4, delivering better video quality at lower bitrates.
The .vp5 file extension represents the video codec used to encode the video in the file. The .vp3 file extension also represents the VP3 codec used in .VP3 files.
The VP5 format was primarily used in the early-2000s for streaming recorded video or live broadcasts over the web to computers, wireless devices, and gaming devices. The video format was most commonly utilized by the RealNetworks RealPlayer media player.
NOTE: On2 Technologies was acquired by Google in 2010.
You can open and play VP5 videos with the free VLC media player, which is available for Windows, macOS, and Linux.
You can also convert a VP5 file to a more common video format with FFmpeg, then open the converted file with a media player, such as Microsoft Windows Media Player (Windows) or Apple QuickTime Player (macOS).
Updated: June 21, 2020