Surveillance HDD for DVR

The advantage of video surveillance dedicated HDD for DVR

From incomplete statistics, the 60% of problems for standalone DVR are derived from the hard driver (HDD). With the new technology development, video data storage are increasing with geometric growth speed, it’s very tricky, once hard driver with problem and lost data. When these problems happen, security installer need to offer free door to door maintenance service for customers, this will not only increase the business cost, but also damage the reputation.

What’s the video surveillance dedicated hard driver (HDD) ?

In order to solve the problem which is caused by the hard driver, the standard alone DVR should install video surveillance dedicated hard driver for video storage. The video surveillance dedicated hard drivers are with same appearance as normal PC hard driver, but with different technical parameters. Utilizing the video surveillance dedicated hard driver (HDD) can keep video surveillance system continuously working without HDD error and decrease the data lost risk. Example: Seagate SV35 is industry standard hard driver for video surveillance system. Seagate Barracuda series are for desktop computer. 

The difference between surveillance dedicated hard driver and traditional PC hard driver.

1. Difference on continuous working time

The continuous working time for traditional PC HDD is based on 5 x 8 ; 5 x 8 means HDD continuous working on 8 hours per day, and 5 days per week (HDD working means HDD in reading and writing status). Please note after power up HDD, there are two status: working status and suspend status, working status means HDD is reading/writing data, suspend status means HDD is not reading or writing, in ready status.

The video surveillance dedicated hard driver (e.g: SV35) is based on 7 x 24 continuous working, it’s industry grade design. 7x24 means every day working 24 hours and seven days per week (ie continuous work).

Traditional (ordinary) PC hard drive is not suitable for long time reading and writing, PC hard driver continuous working for a long time to read and write data will make noise, and cause read/write data errors, interruption…etc many problems, and eventually cause data lost. 

Standalone digital video recorder (SDVR) need continuous run, thus requiring video storage HDD must can be in long time continuous working, video surveillance dedicated HDD can meet this requirement.

2. Power management (Start up current is different)

All 3.5 inch HDDs contain two motor system (spindle motor and actuator arm motor), thus when power up the HDD, the HDD will need large current in initializing stage to complete HDD start up. If the power supply can not provide efficient current, the HDD can not start up successfully, lead to HDD can not use. More over, too much start up failure likely to cause damage to the HDD.

With reason of HDD get the DC12V power supply from external power, thus external power supply DC12V is the standard for measurement of HDD start-up current. Traditional PC HDD start up current is among 2.8A – 3.2A. Video surveillance dedicated HDD start-up current is 2.0A.

Typically standalone digital video recorder adopts multi-HDD for video storage, installing 8 units HDD as an example: Traditional PC HDD start up current is 2.8 x 9 = 22.4A, the lowest power consumption is 22.4A X 12V = 268.8W. The video surveillance dedicated HDD start up current is 2.0A X 8 = 16A, the highest power consumption is 16A x 12V=192W. From above data, with same quantity of HDD, video surveillance dedicated HDD with low current requirement (With same external power supply, the digital video recorder can install more video storage dedicated HDDs).

Currently, based on the reliability of video surveillance systems from highest to lowest, the video surveillance systems can divide into the following levels:

• Residential class reliability: Low reliable, low cost design level, to meet daily consumption needs, usually system is designed for meeting the basic 5x8 hours continuous working reliability. The system running in normal 8 hours daily, may experience frequent downtime, reset, recording interruption…etc errors.
• Commercial-grade reliability: Medium, medium-cost design level, the system can meet long time continuous working reliable operation requirements, but system may also experience downtime, reset phenomenon.
• Carrier-class reliability: The system with 7x24 hours continuous working design, high reliability, and very rare rate on downtime, reset errors. 

Difference between CCD VS CMOS

CCD VS CMOS in video surveillance cameras

There are two different types of cameras in the video surveillance cameras; CCD cameras and CMOS cameras. Now these two types cameras dominated the surveillance market. Thus, how much information we obtained about CCD (charge coupled device) camera and CMOS (complementary metal oxide semiconductor) camera? What are differences between them?

CCD are more sensitive to the light

Sensitivity is one of major difference between CCD camera and CMOS camera. With results of different material to form the image, CMOS sensor with 10 times lower sensitivity than CCD sensor. Human eye can see the objects under 1LUX light condition, CCD sensor see target more than human eye can do, under approximately 0.1 – 3Lux light condition, it’s 3-10 times than CMOS sensor. The sensitivity for CMOS sensor is about among 6-15LUX, CMOS with 10 times of high ratio of noise, compared to CCD sensor, CMOS sensor can not be used under 10LUX light condition lead to CCD sensor widely used for majority of video surveillance cameras. Typically, CMOS sensor is used for low-cost cheap home appliance products. The material for CCD sensor are expensive than material for CMOS sensor.

ACD also is important.

Then, what’s the reason caused CMOS without good sensitivity than CCD? Let’s take up this on next paragraph.

The first difference between CCD and CMOS is the difference of structure of pixel sensor unit. Except contain light photons semiconductor, CCD consists of many MOS (Metal Oxide Semiconductor) capacitors. CMOS sensor construct is more sophisticated, except the photons semiconductors, it included with amplifier and A/D circuit. Compared to CMOS sensor, CCD sensor with large sensitive fields, it can generate strong electric signal in the same environment condition; from the output of image, CCD sensor can provide low-noise and high-quality images. That’s the reason why traditional CMOS sensor is not as good as CCD sensor.

However, since the developing of technology, now there are impressive improvement for the CMOS sensor, with low-cost advantages, CMOS sensor start to challenge the dominate CCD sensor in high end market.

ADC (analog/digital converters) position and quantities are different

CCD and CMOS consist of different ADC design and quantities. Each line of pixel of CCD sensor connect with one ADC, after the exposure is complete, the charge is transferred into a read-out register, and from there to an output amplifier, ADC and on for processing; Each pixel for CMOS connect to one ADC, electrical signal went through amplifier and convert to digital signal.

CCD sensor output analog signal, CMOS sensor output digital signal.

CCD sensor and CMOS sensor with difference between signal processing, the previous adopts analog signal, with parameters of line, the CMOS adopts digital signal, with parameter of pixel. Surveillance cameras that use IP network for transmission are using CMOS sensor, the traditional surveillance camera are using CCD sensor.

After the development of last few years, design improvements for CMOS sensor have increased the light sensitive area to near the level of CCD sensors. In addition, CMOS sensor with advantages of simple structure, low-cost, low power consumption. CCD sensors can work better in night condition, but CMOS sensor can provide 100 million pixels HD high quality images, that’s the CCD sensor can not achieve.

ONVIF - Training of IP Camera Standard/Protocol 

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Analog CCTV cameras have no problem for compatibility. Basically, conventional CCTV cameras and DVRs can work together across different manufacturers. In early IP surveillance development, the IP surveillance system was heavily hampered by the lack of compatibility of equipment and low degree of flexibility in terms of future expansion. Companies engage in IP camera development and manufacturing have their own standard/protocol. Consequently, user only can choose all the equipment (including front-end cameras, back-end storage device) from the same company. After several years chaotic development, in which the manufacturers were introducing their ow standards for transmitting and recording video in IP video surveillance systems.

ONVIF - IP-based Security Standard

In 2008, Sony, Bosch, Axis companies established an organization called Open Network Video Interface Forum (ONVIF). ONVIF aims to solve the IP surveillance systems interoperability between products regardless of manufacturers. It is committed to make a common standard to accelerate the adoption of IP surveillance system. ONVIF has standardized the digital interface of IP surveillance products and unifying compression and transmission of video and audio stream, IP device discovery, Pan/Tilt/Zoom (PTZ) control, Alarm inputs and outputs, configuration and control procedures, motion detection etc. After seven years development, ONVIF has many standard versions including ONVIF 1.0, ONVIF 2.0, ONVIF 2.2, ONVIF 2.4, ONVIF 2.5

The core concepts of ONVIF are:

• Standardization of communication between network video devices
• Interoperability between network video products regardless of manufacturer
• Open to all companies and organizations

What about ONVIF Profiles?

At the beginning, the ONVIF standard encountered problems with the lack of compatibility between some versions. Therefore, in 2012 the organization introduced the concept of "profiles" which is continuously developed. The "profiles"allows for easy and effective check of the conformity of IP surveillance products without analyzing technical details. Undoubtedly, when devices and software are based on the same profile, they are compliant without a doubt. Currently, ONVIF has three profiles, each of profiles has different features. 

Profile Q (ONVIF Q): Addresses device discovery and configuration, as well as the management of TLS certificates and keys

Profile G (ONVIF G): Address configuration of recording and searching, playing back the video on the IP-based security device.  It supports operations on video, audio and metadata.

Profile C (ONVIF C): Supports integration with physical access control system, addressing interoperability between these systems and network video systems. Profile C conformant devices within the access control system provide door and access point information and functionality related to basic door control activities such as locking and unlocking doors, when a door has been accessed and other door monitoring tasks.

Profile S (ONVIF S): Focuses on common functionalities of IP video systems, i.e. specification of audio and video streaming between the device (e.g. camera) and client (software app, NVR). The client can configure the audio, video, and data streams, select PTZ protocols, make use of metadata, alarm inputs and relay outputs.

In conclusion, ONVIF Profile allows user to more easily identify features supported by a profile without knowing the compatibility between ONVIF versions. In addition to Profile C for physical access control system, ONVIF offers Profile Sas the interface to stream video and audio between conformant devices and clients, and as well as Profile G, focuses on video storage, searching, retrieval and playback.

ONVIF vs PSIA

In addition to the ONVIF, there are other organizations intend to establish the standards for network security products. The most active one is PSIA. Physical Security Interoperability Alliance (PSIA) has a mission to bring true plug-and-play interoperability across the different security products and services - cameras, security sensors, access control, video analytics, physical security information management. The problem of PSIA is a low popularity - it currently brings together fewer than 50 companies (including Cisco, GE, Hikvision, IBM, NICE, Pelco, Milestone, Genetec). Meanwhile ONVIF Alliance has over 500 members that offer more than 5000 products compliant with the ONVIF standard.

Why ONVIF does not work?

The most majority IP-based security products claim to compliant with ONVIF standard. However, when end-users try to install these devices marked with this standard might encounter some problems, such as network video recorder can't discover the IP cameras in the same LAN network, motion detection doesn't work. Why is this happening?

First, you need to verify that your installed devices are truly compliant with ONVIF standard. Some manufacturers often mark their products as compatible with ONVIF, although this is not true. It's better to buy/use the IP-based security products from members of ONVIF. You can find the full list of members/manufacturers who are verified to offer ONVIF compliant products.

Second, it's not possible to be ONVIF compliant only; the IP-based security products need to be compliant to a Profile as well. You can be ONVIF conformant only, but if you are it is not guaranteed that you would get interoperability between other ONVIF devices and clients. To truly reap the benefits of ONVIF, you need to be Profile S compliant as it dramatically increases the chance of things like video and audio streaming or video configuration and multicast actually working well together.

One may encounter cases within a set of devices with Profile S, having no problems with connectivity and video streaming, but with some functions (e.g. motion detection). It is usually caused by errors of the standard or, more often, by an incorrect implementation of the standard/profile made by the manufacturer. Such problems should be immediately reported to the manufacturer that, in turn, should release improved software. ONVIF forum is heavily working on new, improved versions of the standard, which will be debugged and more precise in terms of terminology.