Video recordings (.dav) made using DVR-1600HP cameras (and perhaps other devices from the same company) can be potentially exported or converted to other multimedia format, such as MP3 (audio only).
Unfortunately, only handful of programs support DAV format and the best pick seems to be Bigasoft Total Video Converter.
Just keep in mind that the resulting file will only have the audio track, not the video. If you want both, you need to convert it formats like MP4.
Updated: January 11, 2017