CCTV Video Storage & Retrieval Systems 2 — Questions and Answers
Question 1: What is the purpose of RAID in a CCTV storage system?
- To increase the video frame rate
- To provide data redundancy and fault tolerance across multiple drives (Correct answer)
- To compress video files more efficiently
- To encrypt footage for secure transmission
Correct answer: To provide data redundancy and fault tolerance across multiple drives
RAID (Redundant Array of Independent Disks) distributes or mirrors data across multiple drives to protect against data loss if a single drive fails.
Question 2: Which RAID level mirrors data across two drives, providing full redundancy with 50% usable capacity?
- RAID 0
- RAID 1 (Correct answer)
- RAID 5
- RAID 6
Correct answer: RAID 1
RAID 1 mirrors identical data on two drives; if one fails, the other contains a complete copy, but only half the total capacity is usable.
Question 3: Before exporting CCTV footage as evidence, the operator should:
- Delete the original file to save space
- Create a hash checksum to verify file integrity (Correct answer)
- Re-encode the file to a smaller format
- Edit out irrelevant sections
Correct answer: Create a hash checksum to verify file integrity
Generating a cryptographic hash (e.g., MD5 or SHA-256) before export establishes a verifiable chain of custody by confirming the footage has not been altered.
Question 4: What term describes the process of searching stored video to find a specific recorded event?
- Video encoding
- Video retrieval (Correct answer)
- Video streaming
- Video calibration
Correct answer: Video retrieval
Video retrieval is the process of locating, accessing, and playing back specific recorded footage from a DVR/NVR based on time, date, camera, or event criteria.
Question 5: Which feature allows a CCTV system to immediately locate recorded footage triggered by a specific alarm or sensor event?
- Time-lapse playback
- Event-based or alarm-triggered recording index (Correct answer)
- Analog signal boost
- Pan-tilt preset recall
Correct answer: Event-based or alarm-triggered recording index
An event-based recording index tags footage segments tied to alarms or sensor triggers, enabling operators to jump directly to relevant footage without scrubbing through hours of recording.
Question 6: Offsite or cloud backup of CCTV recordings is primarily used to:
- Increase camera resolution
- Protect footage from on-site theft, fire, or hardware failure (Correct answer)
- Reduce the number of cameras needed
- Improve live video streaming quality
Correct answer: Protect footage from on-site theft, fire, or hardware failure
Offsite or cloud backup ensures footage survives local disasters, theft of recording equipment, or hardware failure by maintaining a separate copy at a remote location.
Question 7: What does the term 'bitrate' refer to in CCTV video storage?
- The number of cameras on a single channel
- The amount of data processed or recorded per second (Correct answer)
- The physical length of the recording cable
- The screen size of the monitoring display
Correct answer: The amount of data processed or recorded per second
Bitrate measures the amount of video data (in bits per second) recorded or transmitted; higher bitrates produce better quality but require more storage space.
CCTV Video Storage & Retrieval Systems 2
What is the purpose of RAID in a CCTV storage system?