As I understand it, "PVR" is a generic term. Please share more details about the file! What is its extension? (.pvr?) What device/software/... created it? How did it end up on your computer?
In general though, I'd suggest at least trying ffmpeg for conversion.
If you're on Windows, you can find builds at ffmpeg.zeranoe.com. If you use Ubuntu or Debian, sudo apt install ffmpeg should do the trick, but YMMV.
After downloading, extract the files, open up a command prompt (or PowerShell) in the extracted bin/ directory, and run ffprobe -i your_filename_here (you can drag a file into your command prompt or PowerShell window to expand it into a path) to have FFmpeg try and recognize the file. If it looks successful, you can try ffplay to play the file, or ffmpeg -i your_filename_here -crf 25 -preset veryfast out.mp4 to (try to) convert it into H.264 MP4.