When configuring your DVR for optimal recording, there are many options you will be considering. Among them is the resolution you want to record in. While most DVR’s can record in CIF resolution (360×240) at the maximum frame rate provided by the DVR, some can also record at higher resolutions by reducing the frame rate. For example, you may be able to record on any channel at CIF resolution at 30 frames per second, but then you would probably only be able to record at 7.5 fps per second if you changed the resolution to 4CIF (704×480). You will have to decide for each camera (assuming your DVR has independent resolution settings for each channel) which resolution you want to record in. Remember, what you see is not always what you get! Most DVR’s will display live video in 4CIF or D1 (720×480) resolution, but they are often recording in a much lower resolution.
Each application has different needs. If you are using the security camera for a general overview, you may want to use CIF resolution and the maximum frame rate since detail is less important and fluid video is probably more important. On the other hand, if you are using the camera for facial recognition at the front door of your business, then you will surely want to record at 4CIF resolution, even if it means sacrificing some of the frame rate. The 4CIF image is literally 4 times larger than the CIF image and therefore can provide you with 4 times the detail. There are a couple of DVRs out there that can give you the best of both worlds, 4CIF resolution while doing 30fps recording on every channel. At this time, I only know of one unit that can offer that. It is the Ultimate Series DVR.
Here are 2 different images taken from an Elite Series DVR. The smaller image was from a CIF (360×240) recording and the larger image is from a 4CIF (704×480) recording. The difference between the two is the size of the image stored on the hard drive.
4 CIF Resolution
As you can see, the 4CIF image is much larger. It will be much easier to capture details from the 4 CIF resolution image, than from the CIF resolution image. Unless you are lucky enough to be working with a DVR that does 4CIF or D1 recording in real time (30fps) on all channels at the same time, you will need to decide for each camera, which resolution is best for that application.