I`m looking for standalone DVR with possibility to remotely (best if via remote software not external keyboard) start/stop recordings from chosen channels (not alarm recording from all channels) by regular user (not admin). 4 channels of video and audio, mpeg4 or h.264 compression.
Any help?

that may be hard to find, as for security reasons most developers arent going to put that option into their remote software, at least not for standard users.

If its PC based though you could get your own small software made for that. Just use findwindow to get the DVRs stop and start buttons/feature and run a customized mini server for that ..

GE has an activeX Developers control that will allow for that also once you program it in your code, thats for their Stand alone DVRs.

you could always setup a encrypted WIFI pipe say a PreN type -will give good performance and you can remote desktop or use VNC etc.
-that goes of any IP cam also

my 2c