IP Monitoring with ACTi - Questions & Answers

* What is IP camera and high speed PTZ camera?
* What is the difference between web camera and IP camera?
* What is the required throughput for IP camera?
* Is it possible to record images from IP camera?
* Does one need to have Internet access to use IP camera?
* Do IP cameras support "Power over Ethernet"?
* What are the advantages of MPEG-4?
* Why MPEG-4 ASP is better than Short header?
* What is the advantage of MPEG-4 ASIC over DSP?
* Why is it so important to have DDNS support?
* What does it mean "Time Code Embedded"?
* What for two ports (WAN and LAN) are needed in videoservers?
* Do ACTi cameras have motion detection function?
* What does the included software pack contain?
* Where may IP cameras be used?
* What is a videoserver?

What is IP camera and high speed PTZ camera?

IP is the acronym of Internet Protocol, the most popular protocol used for communication within any computer network or the Internet. IP camera provides at its output digital stream of data corresponding to the video information, which is being transmitted via wired or wireless IP networks, and can be viewed or recorded even in most remote locations in the network.

Employing IP cameras, both regular ones and with PTZ control, the user may save a lot of expenses connected with transmitting infrastructure, as majority of existing buildings, office blocks etc. is equipped with adequate network cabling. The same applies to newly-constructed ones, because standard installations are always cheaper than specially laid coaxial cabling usually needed for non-IP solutions. IP-based system is not only cheaper to build, but also ensures higher level of functionality, allowing to place cameras in any location in relation to the monitoring center.

What is the difference between web camera and IP camera?

Web camera has to be connected to a PC, usually via USB interface, and the computer is used to enable other users to access it. IP camera is autonomous device that combines itself features of high-quality web camera, and PC with network adapter.

What is the required throughput for IP camera?

It depends on the resolution of the image and the number of transmitted frames per second. It is also dependent on compression method being involved. In the table below we give the values for the three most popular algorithms, for a combination of parameters.

It may be well to add that 30 fps (NTSC) corresponds with the quality of smooth TV picture (DVD quality).

Is it possible to record images from IP camera?

Yes. There is possible local or remote recording, with use of the software supplied by the manufacturer of IP camera. The remote recording function is a great advantage of IP devices in comparison with analog ones. The registered video data can be stored in NAS (Network Attached Storage), which is very useful and easy to use.

Does one need to have Internet access to use IP camera?

No. IP cameras may work in local network not connected to the Internet. Such a solution can be used when all points (cameras) and users (terminals) are connected to the same LAN.

Do IP cameras support "Power over Ethernet"?

Growing number of models of ACTi cameras are having PoE versions. But there is always the possibility of adapting other version to PoE with the use of modules connected at switch/router side and camera side.

What are the advantages of MPEG-4?

MPEG-4 can ensure DVD quality, but due to more advanced algorithms it uses, lower data rate is needed. This fact makes possible to transmit the video data stream not only in LAN, but also in WAN, where bandwidth may not be guaranteed. MJPEG requirements are not much higher than MPEG-4, but resolution and fps numbers are lower. MPEG-2 means DVD quality (similarly to MPEG-4), but its demands are so high that cannot be accepted in LANs or WANs.

Why MPEG-4 ASP is better than Short Header?

There are different kinds of MPEG-4 compression. The most popular are MPEG-4 ASP (Advanced Simple Protocol), MPEG-4 SP (Simple Protocol), or MPEG-4 Short Header. MPEG-4 ASP generates frames of I, P and B type, which improves compression factor, whilst MPEG-4 SP and MPEG-4 Short Header give only I and P frames. MPEG-4 ASP and MPEG-4 SP are implemented on ASIC chips (Application Specific Integrated Circuit), whereas MPEG-4 Short Header uses DSP circuit (Digital Signal Processor). The answer is: with the same picture quality the band needed for transmission is considerably lower, or - with the same band - the quality of picture is higher.

In the pictures below we show comparison of quality of images from ACTi videoserver and a rival one, using MPEG-4 Short Header version. Although they both use MPEG-4 compression, the class of ACTi device can be easily noticed, giving the proof of superiority of the employed MPEG-4 ASP kind.

What is the advantage of MPEG-4 ASIC over DSP?

Popular digital signal processors (DSP) do not have enough computing power to encode video into MPEG-4 at D1 resolution (720 x 480) and 30 fps, so that they provide images of lower quality ( CIF - 360 x 240). ASIC chips (Application Specific Integrated Circuit) can perform that operation, ensuring the D1 resolution.

Why is it so important to have DDNS support?

When a device supports DDNS (Dynamic Domain Name Server), the users are able to set a domain (e.g. camera1.london.uk) having only dynamic IP address (which is usually a cheaper option of Internet access). This makes it possible for other sites on the Internet to establish connections to the device.

Some producers of IP cameras claim that their devices support DDNS, but they anticipate use of additional software that each user must install on their PC. ACTi cameras have built-in DDNS utility, so that they don't require any other means - the user is able to reach the camera from any place in the world.

Screenshot of Web Configuration window of ACTi cameras

What does it mean "Digital Time Code Embedded"?

Professional IP cameras (e.g. ACTi) have the function "Digital Time Code Embedded" that is used in creating MPEG-4 data stream. The function allows for permanent real-time labeling of each registered frame. Due to this information it is very easy to find any sequence for given time that is interesting for the user. Without such a function the user would have to browse extensive material, wasting a lot of time. Some other cameras are supported by program measures, but they usually don't ensure exact marking. Video stream marked with "Digital Time Code Embedded" is also called "Smart Video" and it is the key to performing many applications suitable for users of the system.

The next advantage of "Digital Time Code Embedded" utility is the fact that this label is a kind of watermark for video stream. Any attempts of modifying the material will end up in destroying the code. So it is easy to confirm or question the authenticity of recordings.

What for two ports (WAN and LAN) are needed in videoservers?

Professional IP cameras should have the ability to adjust transfer rate (video stream bandwidth) appropriately to network capacity. A step forward is the solution implemented in IP cameras of ACTi. They are equipped with two RJ-45 connectors: LAN and WAN. It makes possible to link the camera to LAN, parallel to Internet connection. In order to ensure relevant bandwidth during streaming video material via the Internet, the WAN port has been fitted with QoS (Quality of Service) feature.

It also supports PPPoE (Point-to-Point Protocol over Ethernet), allowing connection of IP camera directly to ADSL modem. In case of extensive installations, cameras with PPPoE function will allow for considerable savings on buying routers.

Do ACTi cameras have motion detection function?

Yes. This function is embeded in ACTi cameras. The difference between this kind of realization and common program measures is that in the first instance the reaction is immediate, whereas in the second case there is always some noticeable time needed for it.

What does the included software pack contain?

Together with its products, ACTi provides SDK pack (Software Development Kit) and simple application "Streaming Activator". Additionally, one can use "IP Utility" program application for searching IP devices in the network and another program for easy configuration with IE.

Where may IP cameras be used?

IP cameras are the best solution in the case of professional surveillance systems. They allow for live monitoring performed by authorized staff situated a long way from the observed place. They can be easily merged into larger systems. The cameras can be used in all kinds of places, like buildings, public utilities, industrial works, banks, supermarkets and shops, casinos, construction sites etc. The images can be analyzed in the monitoring center, police stations etc.

The cameras are also very useful in public places, where they replace analog equipment. The images from them are then analyzed in monitoring centers, police stations, or by security guards. Another application is in access control systems. Both people and vehicles can be registered together with time markers that facilitate quick access to recordings in big data bases. Due to remote recording capabilities, the whole system is well protected against possible theft of recordings - they can be stored in a distant, safe place.

IP cameras can easily be connected to the existing IP network and give real-time preview from any point of the net. They often are employed in businesses and offices - reception or conference room can be monitored to control persons who enter the rooms. There are also some sensitive places like server rooms that should specially be guarded from interference - in any suspicious case the recorded data will allow to find out who and when worked there.

IP cameras may also be an invaluable tool in production plants. Monitoring of production lines straight from the office or even home may increase productivity of workers and quality of products. PTZ (Pan/Tilt/Zoom) cameras will enable to view both the whole area and the small details.

What is a videoserver?

This term describes a network video device, e.g. working in LAN. Videoserver provides live video data stream automatically or on demand, via a browser or with use of dedicated software. To date, surveillance systems are mainly based on analog CCTV (Closed Circuit TeleVision). Videoservers encode the analog signals into digital data stream enabling to distribute it via IP network, simply transforming analog cameras into IP equivalents. Using modems they can be connected to PSTN or ISDN telephone lines.