It should be quite possible to convert video recordings from Mace DVR-1600HP device (*.dav) to now common Matroska MKV files with programs like HandBrake or similar alternative.
Convert DVR365 encrypted video recording to Matroska multimedia container.
We found 4 software records in the database related to .dav to .mkv file format conversion.
Microsoft Windows software - convert dav to mkv on Windows
A free multiplatform multimedia transcoder
Convert from dav file format
The tables with software actions are a good pointer for what a certain program does with various file types and often may give users a good hint how to perform certain file conversion, for example the above-mentioned dav to mkv. However, it is not perfect and sometimes can show results which are not really usable because of how certain programs work with files and the possible conversion is thus actually not possible at all.
A video conversion utility
Apple macOS / Mac OS X software - convert dav to mkv on OS X
HandBrake for OS X is a free and poplular multimedia and video conversion utility.
Linux/Unix software - convert dav to mkv on Linux
HandBrake for Linux is free multimedia transcoder.