So, can you provide the manufacturer's name of this 4 channel usb 2.0 DVR? Also, is a SDK kit provided and do you have any technical specs for this hardware?
AFAIK, very few DVR manufacturer's open up their hardware by providing SDK's. The only two that I'm aware of are Dahua and Axis. The Dahua brand is not sold in North America under that name. The Dahua line is usually rebranded as Qvis, Mace or some other brand name. Keep in mind that these are quality stand alone DVR's near the high end of the market.
I'm currently developing a Net app to interface with Zoneminder which is a open source Linux DVR system. You may want to look at Zoneminder as a possible option.
the manufacturer is Easypac and I had nothing like SDK kit or hardware specs .It is my first time to deal with such problems. If this DVR is not suitable I can buy a one that corresponds to my needs. what I really need is to develop an alarm system when the alarm is triggered I need the DVR to record and then I need to manage these recordings in my program. I have no idea if I need to make a database or if there are DVR that comes with embeded database. please can u help?
I would strongly suggest not attempting to develop your application with Easypac since there isn't any SDK/techDos and/or support. Capturing a video stream from a DVR to your application is very challenging with good support such as documentation/forums etc. Without support, it will nothing short of a nightmare.
Are you aware that just about all the standalone DVR systems have alarm inputs. Thus, when an alarm is attached to the DVR alarm input and it is triggered, it will start DVR recording. An example would be to attach a Passive Infra Red (PIR) motion detector to the DVR alarm input. When the PIR is tripped, it will cause the DVR to record.
There are no "databases" per se in a DVR. It records streaming video using a compression format called a codec. The most popular format is H.264.
The two SDKs that I'm aware of are:
Axis which is high end equipment geared towards the banking and retail sectors. This quality hardware is very expensive.
Dahua which is a China based organization. Their equipment is popular in Europe. In the US, it's rebranded as Qvis, Mace etc. There is one website that offers substantial discounts on DVRs...Nelly's Surplus. Contact them to get details on a rebranded Dahua.
One last option is to purchase a PC capture card and use a open source DVR such as Zoneminder . A good 4 channel capture card will cost about $150.00.
Depends on how the DVR works. If you are lucky, you can connect to it on a different port per camera and stream video over http. Have you looked into any of the documentation for your DVR? Generally people here give help on the programming aspect, it will be up to you to figuire out the hardware/hardware interface part (unless you're lucky and someone has worked with the same hardware as you recently).