How to playback/convert a DV4 file? I have two .dv4 files, taken from a CCTV and I cannot find a way to use them on either Windows or OS X.

I've tried to open them with several applications, but to no luck!

Does anyone have experience with this kind of files?

Any help will be really much appreciated.
Try VLC or AvTech PlayLite (appears to be abandonware). However, from my cursory research, it seems that DV4 videos are supposed to be bundled with proprietary software (check this Bosch PDF, page 13), so if you're missing that, you might be out of luck.