Monitoring camera definition (resolution) Introduction

Source: Internet
Author: User

Common video image quality has the following types:


qcif:176*144;

cif:352*288; VCD Quality

2cif:704*288;

4CIF (D1): 704*576; that is, D1,dvd quality

Half d1:704*288;

Wd1:960*576 is a clearer adaptation to the widescreen resolution based on the D1.

HD 720p:960*720 or 1280*720; 1 million pixels.

HD 1080p:1920*1080; 2 million pixels.


QCIF Full name Quarter Common intermediate format. QCIF is commonly used in standardized image formats. In the protocol cluster, the standard acquisition resolution of video acquisition equipment is specified. QCIF = 176x144 pixels.

CIF is a commonly used standardized image format (Common intermediate format). In the protocol cluster, the standard acquisition resolution of video acquisition equipment is specified. CIF = 352x288 pixels |

The CIF format has the following characteristics:

(1) The spatial resolution of the TV image is the resolution of the Home video system (video Home SYSTEM,VHS), which is 352x288.

(2) Use non-interlaced scanning (non-interlaced scan).

(3) with NTSC frame rate, the maximum frame rate for a TV image is 30 000/1001≈29.97 amplitude per second.

(4) Use 1/2 of the PAL horizontal resolution, or 288 lines.

(5) The brightness and two chromatic aberration signals (Y, CB and CR) are encoded separately, their value range is the same as the ITU-R bt.601. That is, black = 16, white = 235, the maximum chromatic aberration is equal to 240, the minimum value is equal to 16.

The following is a description of the parameters for 5 CIF image formats. The parameter order is:

Image format luminance sampling number of pixels (DX) Luminance sampling number of rows (dy) chromaticity sampling number of pixels (DX/2) chromaticity sampling lines (DY/2)

SUB-QCIF 128x96 64 48

QCIF 176x144 88 72

CIF 352x288 176 144

4CIF 704x576 352 288 (that's what we often say D1)

16CIF 1408x1152 704 576


Resolution is an important technical indicator in digital surveillance products, which determines the performance (definition, storage, bandwidth) and price of the product to a large extent. To improve the video playback image quality without increasing the cost and data capacity, the resolution is what we need.

At present, the monitoring industry mainly uses QCIF, CIF, half D1, D1 and other resolutions, CIF video resolution is the mainstream resolution, most of the products are based on CIF resolution. The current market to accept CIF resolution, the main reason is four points:

1, the current digital monitoring requirements video stream can not be too high;

2, video transmission bandwidth is also limited;

3, the use of half D1, D1 resolution can improve the clarity, to meet the high quality requirements, but at the cost of high code flow. At this stage, there are many D1 products, but the market share is very small;

4, the use of CIF resolution, signal to noise ratio above 32db, the general user is acceptable, but not the ideal video image quality. At present, the industry is trying to use half D1 to seek the balance between CIF and D1.


What is DCIF?

A more effective monitoring video encoding resolution (DCIF) is found, and its pixels are 528x384. DCIF resolution is the video image of the origin is the odd, even two half D1, by anti-interlaced transformation, composed of a D1 (720*576), D1 as a boundary processing, into 4CIF (704x576), 4CIF by horizontal 3/4 reduction, vertical 2/3 reduction, converted to 528x 384,528x384 the number of pixels is exactly twice times the number of CIF pixels, in order to distinguish with the commonly said 2CIF (704*288), we call it double CIF, referred to as DCIF. Obviously, the DCIF is more balanced in horizontal and vertical two directions than the half D1.


What is D1?

D1 is the standard of display format for digital TV system, which is divided into the following 5 kinds of specifications:

d1:480i format (525i): 720x480 (horizontal 480-wire, interlaced), and NTSC analog TV with the same sharpness, line frequency of 15.25kHz, equivalent to what we call 4CIF (720x576)

d2:480p format (525p): 720x480 (horizontal 480 line, progressive scan), more clear than D1 interlaced scanning, and progressive scan DVD specifications, line frequency of 31.5kHz

d3:1080i format (1125i): 1920x1080 (horizontal 1080-wire, interlaced), HD relaxed with a resolution of up to 1920x1080i/60hz, with a line frequency of 33.75kHz

d4:720p format (750p): 1280x720 (horizontal 720 line, progressive scan), although the resolution is lower than the D3, but because of progressive scanning, more people on the market feel compared to 1080I (actual 540 lines) visual effect more clear. But personally, in the case of the maximum resolution of 1920x1080, D3 than D4 feel more clear, especially the text expression, resolution of 1280x720p/60hz, line frequency of 45kHz

d5:1080p format (1125p): 1920x1080 (horizontal 1080 line, progressive scan), the current civil high-definition video of the highest standard, resolution of 1920x1080p/60hz, line frequency of 67.5KHZ.

The vga:480p format (640*480) VGA supports simultaneous display of 16 colors or 256 shades of gray at a higher resolution of 640x480, while simultaneously displaying 256 colors at the same time in the three-way resolution.

400,000 pixels equivalent to D1 standard: 720x480

1 million pixels equivalent to D4 standard: 1280x720

  1.3 million pixels equivalent to the D5 standard: 1920x1080


One of the D1 and D2 standards is the highest standard of our general analog television, and can not be called high-definition, D3 1080i standard is the basic standard of HDTV, it can be compatible with 720p format, and D5 1080P is only professional standards, not civil level, The above-mentioned 60HZ is only the ideal state of the field frequency, and its line frequency of 67.5KHZ, there is no such high-frequency TV, the actual field in the professional 1080P frequency only 24hz,25hz and 30HZ.

It should be pointed out that the D terminal is a unique Japanese special interface, domestic TV almost no such interface, the most is the color difference interface, and chromatic aberration interface up to D4, theoretically certainly no HDMI (pure digital signal, support to 1080P) the highest resolution high, But on TVs with resolutions below 1920:1080, there is generally no big difference.

  

What resolution does the domestic mainstream DVR (Dvr,digital video recording) adopt? How to calculate hard disk capacity?

The main domestic DVR uses two kinds of resolution: CIF and 4CIF (D1), divided into two models.

The common ways of DVR are 1-way, 2-way, 4-way, 8-way, 9-way, 12-way and 16-way. The maximum can be connected to 8 hard drives, the total capacity of up to 1.6TV, if using CIF resolution, usually calculate the hard disk recorder video drive capacity of 180mb~250mb/hours, usually the value of 200mb/hours, if it is D1 resolution per hour video requires a hard disk capacity of 720MB ~1000mb/hours, usually in order to reduce the capacity of the hard disk can be calculated according to 500mb/hours, the frame rate intelligent set less than 25fps, less code flow!


16-way CIF format 24 hours uninterrupted recording 30 days required hard drive capacity?

16-Way x200mx24 hours x30 days ÷1024m = 2250G, approx. 2.2T


Calculation method of hard disk space occupancy of H. S DVR

A: The hard disk space for each channel per hour calculation formula: [Video bitrate (128-2048)/8*3600]/1024

For example, if the code rate is set to 512K, the disk space per video channel per hour is as follows:

[512/8*3600]/1024=225MB

B: space occupied per channel per day [gb]:a*24

For example: If the code rate is set to 512K, each hour each video channel takes up the hard disk space as follows:

[225mb*24]/1024=5.2734g

C:16 Road DVR occupies a day of space: b*16

For example: Press the 16-way DVR to set the video stream to a fixed 512K, the space occupied by the day is as follows:

16*5.2734G=84.3744GB If you press 1000G a hard drive, recording data needs to be stored for 30 days, the following drives are required:

[30*84.3744gb]/[1000*0.9]=2.8 A


Current market Mainstream code stream support 1-25 frame adjustable, support CIF\QCIF format display, QCIF mainly used for mobile phone display.

How much of the video's size, resolution, and bandwidth is calculated?

Video size is related to data traffic: traffic is probably 1=4cif=4qcif, bandwidth is directly related to traffic!

Based on flash technology traffic:

QCIF general flow of 6-8k around, according to the needs can be adjusted, generally used in mobile phones

CIF general flow is about 10-40k, can be adjusted according to need, apply to network video

D1 general flow is around 80-120k, adjustable according to need, apply to monitor

Traffic monitored by CIF format:

Flow per minute: 30KBPS*60/1024=1.7578125MB

Traffic per hour: 1.7578125MB*60=105.46875MB

Daily Flow: 105.46875MB*24/1024=2.471923828125GB

such as: 26-Channel monitoring point data requirements storage period One months is: 2.471923828125gb*26*30=1928.1005859375gb/1024=1.88t

Based on H264 technology, the volume of data is one times larger than that of flash technology!

Bandwidth can be calculated based on the amount of data on the information point (the number of Access users) (the upper \ Downlink bandwidth is as large)


Common cameras:

Hoi Hong Analog Dome Camera (approx. 600,000 megapixels): ds-2cc51a2p

700TVL 1/3 "CCD night-day dome Camera

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Hoi Hong 1.3 million megapixel dome Network Camera: ds-2cd2110 (D)-I

1,300,001/3 "CMOS ICR day-and-night dome Network Camera

650) this.width=650; "src=" Http://s3.51cto.com/wyfs02/M02/6B/E3/wKiom1U41pijQt-dAAPKu0IC8M0676.jpg "title=" Screenshot2743.jpg "alt=" Wkiom1u41pijqt-daapku0ic8m0676.jpg "/>


Common DVR:

Hoi Hong DVR analog hard disk Recorder: Ds-8104/08/16he-sh

Network hard disk Recorder

1th, 5, 9, 13 channels support WD1/4CIF/2CIF/CIF/QCIF real-time encoding, the remaining channels support CIF/QCIF real-time encoding, or all channels support 2CIF/CIF/QCIF real-time encoding
Support HDMI, VGA, CVBS simultaneous output
Supports up to 16 simultaneous playback and multiple simultaneous rewind

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Hoi Hong NVR Network dvr: Ds-8608/8616/8632/8664n-e8

DS-8600 Series HD Network Recorder (NVR)

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Monitoring camera definition (resolution) Introduction

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