I've just had my first play with some Dahua cameras and DVR. When exporting video clips, they are exported in a proprietary Dahua .DAV movie format. VLC Player recognises it is some kind of H.264 movie and correctly reports it's resolution, but cannot play the file. Fortunately the Dahua DVR also exports a copy of their player software for Windows.

After some digging around, I've found a good and free player of Dahua .DAV files for Mac OS X. It's called Mac Smart Player. There are a number of sites which host this software but you have to pay to download it. However it is publicly available as a free download from Security Camera King.

What I'd love to know is, who wrote this software and what is the original and official source of this software for any future updates? I can find no hint of the source of this software in the application itself.