jameslou

if the DVR does not have this function (e.g. provide a mobile phone program for you to view remotely), there is not way to do this. You have to go for other software that has this feature.

CIF = 352x240 in NTSC and 352x288 in PAL. You may google "Definition of CIF" for more detail definition.

I think the networking problem is not directly related to the DVR cards. There are some factors that has effect: -Network bandwidth (very obvious): to solve this problem, you need to have money. -The data size of each video frame: this significantly depends on the compression quality and video resolution you configured. Do some experiments on the 2 settings and see the result of local file. The data size to send over Network is the same as that to local file. - The key-frame interval (I-frame): Many people ignore this setting. This is a very important setting to avoid big time gap between frames for remote viewing. Set this value to around 2 seconds. Insufficient network bandwidth must cause frames-dropping. If unfortunately a key frame is dropped, all frames until the next key frame will becomes useless and be dropped too (a bad program may even send the garbage frames, which deteriorate the problem). So you should be able to imagine what happens if you set this value high.

If you want a 16 channels (or more) system with resolution up to 720x480, you would need to buy PCI-E based capture cards, or a special motherboard. The standard PCI bandwidth is not sufficient for that high resolution at that many channels. Another problem is recording. If you just need "2fps" and round-the-clock for each channel, it would be easy. A low-price dual-core CPU can do this. But if you want very smooth (at least 25fps) recording for all 16 channels, one recommendation would be to buy one 8 channel PCI-based D1 hardware compression card, one PCI-E based software compression card (general support D1 resolution), and a quad-core CPU (for software compression). And then buy a software that can mix-using hybrid cards.

If the DVR allows you to setup a region of interest, set this up. The DVR probably use a very causal algorithm that just compute the ratio of the number of pixel changed (luminance changed) and the total number of pixel. The "high", "normal", and "low" would just for you to choose a predefined threshold of the ratio to trigger alarm. Setting a region of interest could increase the accuracy by removing uninterested areas.

You may try NovoSun CyeWeb. It support hybrid connection to IP camera, compression card and generic analogy capture cards. It can also record native stream (JPEG/MJPEG) into WMV file.