CCTV Video Storage & Retrieval Systems 1 — Questions and Answers
Question 1: What does DVR stand for in CCTV storage systems?
- Digital Video Recorder (Correct answer)
- Direct Video Router
- Dynamic Video Relay
- Dual Video Receiver
Correct answer: Digital Video Recorder
DVR stands for Digital Video Recorder, the device that captures and stores analog camera footage in digital format.
Question 2: Which storage technology is most commonly used in modern NVR systems?
- VHS tape
- Optical disc arrays
- Hard disk drives or SSDs (Correct answer)
- Magnetic drum memory
Correct answer: Hard disk drives or SSDs
Modern NVR systems use hard disk drives (HDDs) or solid-state drives (SSDs) due to their high capacity, reliability, and random-access capability.
Question 3: What is the primary difference between a DVR and an NVR?
- DVRs are larger in physical size
- DVRs process analog signals while NVRs process IP camera streams (Correct answer)
- NVRs can only store 24 hours of footage
- DVRs require fiber optic cabling
Correct answer: DVRs process analog signals while NVRs process IP camera streams
DVRs process and encode analog video signals locally, while NVRs record pre-encoded digital streams from IP cameras over a network.
Question 4: Video retention policy refers to:
- The resolution at which video is recorded
- The length of time recorded footage must be kept before overwriting (Correct answer)
- The number of cameras a system can support
- The frame rate of the video stream
Correct answer: The length of time recorded footage must be kept before overwriting
A video retention policy defines the minimum and maximum duration that recorded footage must be preserved before it can be overwritten or deleted.
Question 5: Which video compression codec is most widely used in modern CCTV IP camera systems?
- MPEG-1
- H.264 (AVC) (Correct answer)
- DivX
- RealVideo
Correct answer: H.264 (AVC)
H.264 (AVC) is the industry-standard codec for CCTV because it provides high-quality video at significantly reduced file sizes compared to older formats.
Question 6: What happens during a 'continuous loop' recording setting on a DVR/NVR?
- The system pauses recording when motion stops
- New footage overwrites the oldest recordings once storage is full (Correct answer)
- The system records only during scheduled hours
- Recording stops when the drive reaches 80% capacity
Correct answer: New footage overwrites the oldest recordings once storage is full
Continuous loop recording automatically overwrites the oldest stored footage once available storage is exhausted, ensuring uninterrupted recording.
Question 7: When calculating required storage capacity, which factor does NOT directly affect the calculation?
- Number of cameras
- Video resolution and frame rate
- Color of the camera housing (Correct answer)
- Compression codec used
Correct answer: Color of the camera housing
The physical color of the camera housing is cosmetic and has no effect on the data generated or storage requirements.
CCTV Video Storage & Retrieval Systems 1
What does DVR stand for in CCTV storage systems?