Resolutions: VGA vs 720p vs 1080p vs 5MP vs 4K UHD

We're glad to address this frequently asked question, this time giving a little clarity to the differences between TVL and megapixel resolution metrics and how TVL measurements compare to pixel measurements in PAL, NTSC and IP CCTV systems.

For conventional video surveillance cameras, they are analog cameras which output analog TV signals. Accordingly, TV line is used to refer the image resolution that the camera can capture. The resolution of image mainly depend on equipped CCD/CMOS image sensor. Based on different CCD/CMOS image sensor, analog camera can deliver standard resolution video with 700TVL, 650TVL, 480TVL, 420TVL etc. Higher TV line means higher resolution. Now, network camera becomes the mainstream, network camera outputs digital signal, manufacturers use pixel to refer the image resolution, such as 0.3 megapixel, 1 megapixel, 1.3 megapixel, 2 megapixel, 3MP, 5MP, even 8MP ultra high definition. Higher pixel means better image quality and higher resolution.

A television line is a distinct vertical line, alternately black and white, which can theoretically be displayed on a video image from a camera or on a screen. So, 400 TVL would mean that 200 alternating dark and 200 light vertical lines can be captured/displayed by the camera/monitor. This explanation is complicated however, by the fact that the horizontal resolution is expressed in relation to vertical resolution, in effect showing what the horizontal resolution would have been if the TV were square. But TVs are not square, and nor are camera images, indeed they tend to be 4:3.

Respectively, as the video recording and storage devices, Digital video recorder also has different resolution to define its video compression capability such as QCIF, CIF, HD1, D1 (FCIF), 960H (WD1) etc. A typical analog video surveillance system mainly composes of several cameras and DVRs. To achieve required video surveillance quality, both cameras and DVRs should have the same resolution specification, or DVRs may support higher resolution recording capability.

Many clents will confuse between pixel and TV lines, recently we has been asked many questions about the conversion between pixel and TV Lines. If you are also feel confused about them, you can check the following table.

In the past, the high definition (HD) refer to megapixel resolution, and now there is Ultra High Definition (4K) which is 8 megapixel. In the market, there is Full HD, which means the video image’s length and width ratio is 16L:9W, normally means 1920*1080. The "Full" character specially refers to the "16:9" ratio, as in the early days, there is no unified standard, there are also other ratio like for example, 4:3.

Device TVL/Pixel Effective Pixel NTSC Effective Pixel PAL Total NTSC Total PAL
Analog SONY CCD 480TVL 510H*492V 500H*582V ≈0.25 megapixel ≈0.29 megapixel
600TVL 768*494 752*582 ≈0.38 megapixel ≈0.43 megapixel
700TVL 976*494 976*582 ≈0.48 megapixel ≈0.56 megapixel
Analog SONY CMOS 1000TVL 1280*720 ≈0.92 megapixel
IP Camera and NVR 720P 1280*720 ≈0.92 megapixel
960P 1280*960 ≈1.23 megapixel
1080P 1920*1080 ≈2.07 megapixel
3MP 2048×1536 ≈3.14 megapixel
5MP 2592×1920 ≈4.97 megapixel
DVR and NVR QCIF 176*144 ≈0.026 megapixel
CIF 352*288 ≈0.1 megapixel
HD1 576*288 ≈0.16 megapixel
D1(FCIF) 704*576 ≈0.4 megapixel
960H 928*576 ≈0.53 megapixel