Saturday, November 4, 2017

CCTV Recording Resolution

CCTV Recording Resolution

Digital Video Recorders (DVR) and Network Video Recorders (NVR) are the heart of every security camera system. Customers often ask us about recording quality from CCTV cameras, things can seem relatively straightforward: you’ll need a DVR/NVR that can handle as many channels as you have cameras, and the more hard drive space you have for archiving all that video, the better. Naturally a customer wants to know how clear the video resolution will be from a system before making a purchase decision. Final outcome of your captured footage, 


Recording resolution is the number of pixels (dots) used to create an image. Higher resolutions use more pixels to create an image. This means that greater amounts of detail can be expressed in the image, but larger files sizes and a greater amount of storage (i.e. Hard drive space) are required to save the images or video. See the example below.

The resolution is increasing from left to right
Recording resolution is measured as the number of horizontal pixels by the number of vertical pixels (Width x Height). The following table shows some common recording resolutions.
Name
Width (Horizontal Pixels)
Height (Vertical Pixels)
Total Number of Pixels
Recommended Camera Equipment
CIF
360
240
86,400
320TVL, 400TVL, 420TVL, 480TVL,
2CIF
720
240
172,800
420TVL, 480TVL, 540TVL
VGA
640
480
307,200
540TVL, 600TVL, 1MP
D1
720
480
345,600
600TVL, 650TVL, 700TVL, 800TVL
720p
1,280
720
921,600
720p, 1.3MP
QVGA
1280
960
1228,800
960p, 1.3MP
1080p
1,920
1,080
2,073,600
1080p, 2.1MP
3MP
2048
1536
3145,728
3MP
5MP
2560
1920
4915,200
5MP
6MP
3032
2008
6088,256
6MP
8MP
3264
2448
7990,272
8MP

Notice the increase in the total number of pixels as the resolution increases. Because the total number of pixels is determined by the number of horizontal pixels times the number of vertical pixels, if both horizontal and vertical pixels are doubled, the total number of pixels increases by a factor of 4. This means that the amount of hard drive space needed to store an image or a given duration of video will also increase by a factor of 4 (given factors such as the frame rate remain equal). It is recommended to try different configurations on your system to balance image quality against the amount of storage space available.

Now based on the capabilities of your DVR you may choose to record in a certain picture resolution based on certain requirements unbeknownst to anyone but you.

I have seen a lot of misconceptions of the newly introduced 960H. Amongst the confusion, I have seen a statement along the lines of 960H provides you a 960x480 and/or 720x480 picture; as well that it improves the picture of any camera fitted with a 960H sensor via your current DVR. This is a BIG misconstrued myth. Submitted for your approval are the facts of 960H
1.   960H is NOT a megapixel resolution
2.   960H sizes are NOT 960x480 or 720 x 480 formats
3.   Cameras equipped with 960H alone, will NOT provide you with a refined captured footage of 960x480

The graphic below shows a comparison of the resolutions listed if each pixel takes up the same amount of space.


F.Y.I For all footage across every system, after video is recorded it can be magnified (zoomed in) but only digitally either through a computer or the DVR (if capable). That means, the individual pixels that create the picture can be made bigger. However, for analog footage, there will be no real advantage at detail due to the low-res of pixels.

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