1. What is the compression ratio for a 1-MB image that is compressed to 128KB?
   a. 1:1
   b. 2:1
   c. 4:1
   d. 8:1
   e. 16:1
   
   
2. A technique that uses a mathematical calculation to create missing data in an image is called:
   a. artifacts.
   b. interpolation.
   c. progressive scan.
   d. lossless.
   e. None of the above
   
   
3. The blemishes or distortions in an image generated by electrical noise is called:
   a. artifacts.
   b. interpolation.
   c. progressive scan.
   d. lossless.
   e. None of the above
   
   
4. Which of the following is an example of a digital video format?
   a. H.264
   b. Wavelet
   c. MPEG
   d. All of the above
   e. None of the above
   
5. All RAID systems incorporate redundancy providing no loss of data even with a single disk failure.
   a. True
   b. False
   
   
6. 30 frames per second is equal to how many fields per second?
   a. 15
   b. 30
   c. 45
   d. 60
   e. None of the above
   
   
7. Digital video image files degrade with each viewing.
   a. True
   b. False
   
   
8. In a digital video recording system, the compression technique employed will impact the:
   a. bandwidth.
   b. resolution.
   c. storage requirements.
   d. All of the above
   e. None of the above
   
   
9. Network PTZ cameras always require separate cable runs for video and PTZ control.
   a. True
   b. False
   
10. You cannot incorporate existing analog CCTV cameras into a new network video recorder.
    a. True
    b. False
    
    
11. Limiting the amount of bandwidth that a network video system will consume is called:
    a. integration.
    b. TCP/IP.
    c. saturation.
    d. throttling.
    e. None of the above
    
    
12. All network cameras connected to the same LAN must be programmed with the same internal IP address.
    a. True
    b. False
    
    
13. All network video recorders use a Windows-based operating system.
    a. True
    b. False
    
    
14. UDP and TCP are identical communication protocols.
    a. True
    b. False
    
    
15. Stored video images can be exported to:
    a. a CD-ROM.
    b. a DVD.
    c. the Internet.
    d. a thumb drive.
    e. Any of the above
    

What’s Wrong with This?

Enlarge this picture

Wally ‘Larman installed a digital CCTV system consisting of 10 network cameras and a video server. To minimize installation cost, he ran Cat 6 cables from each camera to the existing network room and connected the video equipment to available ports on the existing data switch, as shown in this diagram. When Wally tested the system, everything seemed to work properly, but soon users complained about the throughput of the network. Can you see what Wally did wrong and what he can do to correct the problem?

5-Minute Tech Quiz Answers

1. d -— The compression ratio is determined by dividing the original size of the file by the compressed size. In this case, 1 MB divided by 128 KB is equal to 8.

2. b

3. a

4. d

5. b — Not all RAID configurations, such as RAID 0, provide backup data protection due to a disk failure.

6. d

7. b — Unlike VHS tapes, the quality of a digital video image is not affected by the number of times it is viewed or copied.

8. d

9. b — Depending on the camera and recording software, it is possible to use a single Cat 6 cable to provide video, data, power and even PTZ controls. Check with manufacturers to determine compatibility.

10. b — You can add existing analog cameras to a new digital video system by installing a video server, which converts the analog signals from the cameras to a digital format that then can be connected to any standard network.

11. d — Some digital video systems provide a means to throttle the bandwidth, either on a system-wide basis or camera-by-camera.

12. b — All network cameras must have their own unique IP address on the network.

13. b — Although many network video recorders use Windows-based operating systems, some employ other systems, such as Linux.

14. b

15. e - Because digital video images are saved as standard data files, they can be exported and saved to any medium that is connected to or available to the system.

Answer to: What's Wrong with This?

Enlarge this picture

Wally’s problem is caused by the video system’s data utilizing too much of the bandwidth of the data network. It may be possible to limit or throttle the bandwidth by making changes to the set-up of the cameras and video server, but this may not be sufficient. A better approach may be to establish a separate video network as shown in this diagram. In this way, the video data from the cameras to the storage server will not have any effect on the throughput of the existing data network. Some network recording devices incorporate two network interface cards (NICs) allowing connection to two different networks, thereby simplifying this configuration.