Video Recording and Storage Flashcards

What is the primary advantage of H.265 over H.264 in CCTV storage?

Answer: Approximately 50% reduction in file size at the same quality

H.265 (HEVC) achieves roughly 50% better compression efficiency than H.264, significantly reducing storage requirements.

In the context of CCTV, what does 'pre-event buffering' mean?

Answer: Storing footage captured before a trigger event occurs

Pre-event buffering continuously holds a rolling window of footage in memory so that video before a trigger (e.g., motion) is also saved.

Which storage topology connects NVRs directly to a dedicated storage network separate from the camera network?

Answer: SAN (Storage Area Network)

A SAN provides a high-speed dedicated network for storage devices, keeping storage traffic separate from the IP camera data network.

What does 'variable bitrate' (VBR) recording mean in CCTV systems?

Answer: The bitrate adjusts based on scene complexity to optimize storage

VBR dynamically adjusts the data rate — using more bits for complex scenes and fewer for static ones — to balance quality and storage efficiency.

A CCTV installation requires 90 days of retention for 16 cameras each generating 2 GB/day. What total storage is needed?

Answer: 2,880 GB

16 cameras × 2 GB/day × 90 days = 2,880 GB of total storage required.

What is 'scheduled recording' in a DVR/NVR?

Answer: Recording that runs only during user-defined time windows

Scheduled recording allows administrators to define specific time periods during which the system will record, conserving storage outside those windows.

Why is RAID not considered a backup solution for CCTV footage?

Answer: RAID protects against drive failure but not against accidental deletion or site disasters

RAID provides redundancy against hardware failure but all copies reside in the same physical location and are equally vulnerable to deletion, fire, or theft.