CCTV / NVR storage calculator

1. How Bitrate is Estimated

Rather than relying on generic flat-rate lookups, this Camera Storage Estimator applies a dynamic calculation model to simulate bandwidth consumption based on real-world camera performance metrics.

The primary formula for active camera throughput is defined as:

Bitrate_Active = baseBR × fpsFactor × K_Codec × K_Scene

Base Bitrate (baseBR)

The baseline infrastructure load is calculated directly from the sensor resolution:

baseBR = Resolution (MP) × 1.3

Example Application: A standard Full HD 1080p camera (approximately 2.07 MP) operating at a baseline of 15 FPS with standard H.264 compression and medium scene complexity results in: 2.07 × 1.3 × 1.0 × 1.0 approximately 2.69 Mbit/s This coefficient is an empirical baseline derived from vendor planning guides to ensure optimal pixel density during active surveillance.

Frame Rate Scaling (fpsFactor)

Bandwidth scaling does not scale linearly with frame rate (FPS) modifications. Because modern encoders capture temporal differences between frames rather than transmitting full static images sequentially, doubling the frame rate yields a sub-linear impact on total volume. The engine applies a power-law curve to model this behavior accurately:

fpsFactor = (FPS / 15)^0.45

This scaling factor avoids capacity over-allocation when designing high-frequency (30 fps) deployments.

2. H.264 vs H.265 Storage Requirements

The efficiency of video compression changes depending on ambient environment noise and motion entropy.

Scene Complexity Modifiers (K_Scene)

• Low (× 0.7): Controlled-access environments with minimal pixel shifting (for example, quiet warehouses or overnight indoor corridors).
• Medium (× 1.0): Standard retail environments or commercial spaces with moderate foot traffic.
• High (× 1.4): Dynamic, unconstrained exterior environments prone to constant motion (for example, busy intersections, crowds, moving foliage, or variable lighting). High noise limits inter-frame compression efficiency.

3. Motion Detection Impact

When record-on-motion configurations are enabled, the platform applies a dual-state duty cycle. During periods of inactivity, the data stream falls to a user-defined Idle FPS ceiling and drops scene complexity to absolute minimum limits (0.7). The net temporal requirement is calculated as:

Bitrate_Mean = (Bitrate_Active × M) + (Bitrate_Idle × (1 - M))

Where M represents the estimated percentage of motion activity across a standard 24-hour cycle. Additionally, if audio capture is selected, an immutable allocation of 64 kbit/s (0.064 Mbit/s) per camera is added to the active budget to account for standard G.711 PCM sound streams.

4. RAID Storage Overhead

Physical drive planning extends beyond raw mathematical volume. The built-in CCTV RAID Calculator module utilizes standard fault-tolerant arrays to determine exactly how many storage tiers must be purchased:

• RAID 1: Pure mirror architecture. Redundancy overhead requires exactly 2.0 × Net Volume, restricted to exactly N=2 disks.
• RAID 5: Single distributed parity. Requires a minimum of 3 drives. Storage allocation loss is exactly equal to 1 drive: N / (N - 1).
• RAID 6: Dual distributed parity. Requires a minimum of 4 drives. Survives two simultaneous drive failures by reserving two drives for parity data: N / (N - 2).
• RAID 10: Combined mirror/stripe array. Requires a minimum of 4 drives and is limited strictly to even-numbered layouts (N mod 2 = 0). Half of the physical capacity (50%) is used for overhead.

Drive Calculation: The engine divides the total fault-tolerant requirement by the drive count (N) and automatically matches the result against standard commercial HDD distribution steps (for example, 2, 4, 6, 8, 12, 16, 20 TB).

5. Storage & File System Overhead

A baseline Overhead option (recommended at 15%) is included in the Video Surveillance Storage Calculation process to absorb systematic capacity losses:

1. Binary-Decimal Translation: HDD vendors calculate storage using decimal notations (10^12 bytes per TB), whereas operating systems format arrays in binary notation (1024^3 bytes per TB). This systemic mismatch reduces physical drive capacity by approximately 7.3%.
2. Metadata Journaling: File systems (such as EXT4 or XFS) isolate a percentage of storage blocks for metadata indexing, file recovery tables, and sector mapping.
3. Guardbands: NVR storage arrays degrade in write efficiency when completely full; keeping a standard 5-10% buffer prevents performance degradation during routine automated FIFO disk purges.

6. NVR Throughput Limits

The calculator triggers an optimization warning if your aggregate system throughput breaks past 320 Mbit/s.

While standard gigabit interfaces manage higher raw data levels, 320 Mbit/s represents the typical recording throughput limits of many mid-range commercial NVR platforms. Exceeding this boundary bottlenecks the internal system-on-chip processing paths or the write speed of the storage database engine. This leads directly to dropped video frames, stream instability, or delayed playback. Systems operating past this threshold require split network layouts across multiple NVR nodes or upgrading to high-throughput project-grade hardware.