Depends on how robust the MOBO in the DVR is. Keep in mind, even if you can, usually the limiting factor is how strong a signal the MOBO can push out. My CO has had this issue on a now discontinued OEM product that was PC based. Robust, but the vid cards were hit or miss if they could even toss enough signal to go through a 15' KVM cable, let alone an entire house's worth.
Composite or analog is going to be your best option without pushing a ton of other devices into the signal chain.