Want to watch DVR via Internet:What is the minimum Internet connection speed required

Hi

I have a DVR (4 Channel) and also a VPN on my Office Network. We have a Dynamic IP but we use ipname and dyndns. I am able to access all Network Resources INCLUDING the DVR via the Internet, Remotely.

The problem arises in the fact that its just TOO SLOW. The images appear on my Remote Screen and then the whole System Freezes. Neither can I see movements, nor close the window.

Does it have to do with the ADSL Speed? We have 512K Download and 128K Upload.