CCTV Video Recording and Storage Questions and Answers — Questions and Answers
Question 1: A financial institution requires a video storage solution for its 64-camera system that prioritizes high data redundancy and can withstand the failure of up to two hard drives simultaneously without any data loss. Which RAID level best meets this requirement?
- RAID 5
- RAID 10
- RAID 6 (Correct answer)
- RAID 1
Correct answer: RAID 6
RAID 6 extends RAID 5 by adding a second, independent parity block. This dual parity allows the array to remain operational and rebuild data even if two member drives fail at the same time, making it ideal for critical applications requiring high fault tolerance.
Question 2: What is the fundamental difference in how a Digital Video Recorder (DVR) and a Network Video Recorder (NVR) handle the video encoding process?
- A DVR encodes video at the recorder, while an NVR receives an already encoded stream from the IP camera. (Correct answer)
- An NVR requires coaxial cable for video input, while a DVR uses network cables.
- DVRs can only record in standard definition, while NVRs are exclusively for high-definition video.
- NVRs store video data on the network, while DVRs only store it on internal hard drives.
Correct answer: A DVR encodes video at the recorder, while an NVR receives an already encoded stream from the IP camera.
The key distinction is where encoding occurs. In a DVR system, analog cameras send raw video signals over coaxial cable to the DVR, which then encodes the signal into a digital format for storage. In an NVR system, the IP cameras encode the video themselves and transmit a ready-to-record digital stream over the network to the NVR.
Question 3: A security manager wants to significantly increase the video retention period for a 16-camera system without purchasing additional hard drives. The monitored areas are mostly inactive overnight. Which change in recording configuration would be most effective?
- Switching from continuous recording to motion-based recording. (Correct answer)
- Increasing the video resolution from 1080p to 4K.
- Changing the compression from H.265 to H.264.
- Increasing the frame rate from 15 fps to 30 fps.
Correct answer: Switching from continuous recording to motion-based recording.
Motion-based recording only saves video when activity is detected. For areas with long periods of inactivity, this drastically reduces the amount of data stored compared to continuous (24/7) recording, thereby extending the retention period on existing storage. The other options would all increase storage consumption.
Question 4: When configuring an IP camera for a scene with highly variable activity, such as a quiet office lobby that becomes crowded during lunch, which bitrate setting most efficiently maintains image quality while optimizing storage?
- Constant Bitrate (CBR)
- Variable Bitrate (VBR) (Correct answer)
- Fixed Frame Rate (FFR)
- Maximum Bitrate (MBR)
Correct answer: Variable Bitrate (VBR)
Variable Bitrate (VBR) allows the encoder to use a higher bitrate during complex, high-motion scenes to maintain image quality and a lower bitrate during simple, static scenes to save storage space and bandwidth. CBR uses a fixed bitrate regardless of scene complexity, which can waste space or compromise quality.
Question 5: A critical infrastructure site uses a Video Management System (VMS) with a primary recording server. To comply with regulations, video recording must continue uninterrupted even if this primary server experiences a complete hardware failure. Which feature is designed for this level of recording redundancy?
- RAID 5 Array
- Failover Recording Server (Correct answer)
- Edge Storage on Cameras
- Redundant Power Supplies
Correct answer: Failover Recording Server
A failover recording server is a secondary, standby server that automatically takes over recording tasks if the primary server becomes unavailable. While RAID protects against drive failure and redundant power supplies protect against a power unit failure, only a failover server can ensure recording continuity during a complete server hardware failure.
Question 6: Which of the following is the LEAST critical factor when an organization defines its video surveillance retention policy?
- The total available storage capacity.
- Applicable industry or legal requirements.
- The brand of the hard drives used for storage. (Correct answer)
- The average time required to investigate an incident.
Correct answer: The brand of the hard drives used for storage.
A video retention policy dictates how long footage is kept, based on legal and regulatory mandates, the practical needs for incident investigation, and the physical limits of storage capacity. The specific brand of hard drives is a procurement and reliability detail, not a factor that defines the policy itself.
CCTV Video Recording and Storage Questions and Answers
A financial institution requires a video storage solution for its 64-camera system that prioritizes high data redundancy and can withstand the failure of up to two hard drives simultaneously without any data loss.
Which RAID level best meets this requirement?