CCTV Video Recording and Storage 2 — Questions and Answers
Question 1: What does the term 'compression ratio' refer to in video storage?
- The ratio of original file size to compressed file size (Correct answer)
- The ratio of frames recorded per second
- The ratio of resolution width to height
- The ratio of bitrate to frame rate
Correct answer: The ratio of original file size to compressed file size
Compression ratio describes how much the original video data has been reduced in size after encoding.
Question 2: Which RAID level provides disk striping with parity, requiring a minimum of 3 drives?
- RAID 0
- RAID 1
- RAID 5 (Correct answer)
- RAID 10
Correct answer: RAID 5
RAID 5 uses block-level striping with distributed parity data across at least 3 drives, allowing one drive failure without data loss.
Question 3: In NVR systems, what primarily determines the maximum number of cameras supported?
- Hard drive capacity
- Processing power and licensed channel count (Correct answer)
- Monitor resolution
- Network switch speed
Correct answer: Processing power and licensed channel count
NVR channel capacity is limited by its processing power for decoding streams and the number of licensed channels.
Question 4: What is 'continuous recording' mode in a DVR/NVR?
- Recording only when motion is detected
- Recording around the clock regardless of activity (Correct answer)
- Recording in a loop that overwrites the oldest footage
- Recording only during scheduled business hours
Correct answer: Recording around the clock regardless of activity
Continuous recording captures video 24 hours a day, 7 days a week without gaps.
Question 5: Which video codec is most commonly used in modern IP camera systems for efficient compression?
- MJPEG
- H.264 (Correct answer)
- MPEG-2
- DivX
Correct answer: H.264
H.264 (AVC) is the industry standard for IP camera systems due to its excellent compression efficiency and broad hardware support.
Question 6: What happens to recorded footage when a DVR's hard drive reaches full capacity in overwrite mode?
- Recording stops until storage is manually cleared
- The system sends an alert and pauses recording
- The oldest footage is automatically deleted to make room (Correct answer)
- New recordings are compressed further to fit
Correct answer: The oldest footage is automatically deleted to make room
In overwrite mode, the DVR automatically deletes the oldest recorded footage to free space for new recordings.
Question 7: What is the purpose of a video management system (VMS) in a CCTV installation?
- To adjust camera lens focus remotely
- To centrally manage recording, playback, and camera configuration (Correct answer)
- To boost analog video signal strength
- To convert IP cameras to analog output
Correct answer: To centrally manage recording, playback, and camera configuration
A VMS provides centralized software for managing camera feeds, recording schedules, playback, and system configuration.
CCTV Video Recording and Storage 2
What does the term 'compression ratio' refer to in video storage?