How to calculate the required hard drive storage capacity for a surveillance system?

To calculate storage capacity, the following parameters need to be considered:

1. Encoding method, such as H.264, H.265, H.265+ (Smart265):
   • Differences between H.264, H.265, and H.265+ encoding standards can be referenced in the standard comparison within the system.
2. Supported encoding methods by the camera:
   • If the recorder supports H.265 encoding but the camera only supports H.264, the recorder can only be set to H.264 encoding.
   • If the recorder supports H.264 encoding but the camera supports H.265, the camera’s encoding method must be changed to H.264, otherwise, the recorder’s decoding will fail and it will store data in H.264 encoding.
   • If both the recorder and camera support H.265 encoding, the recorder will encode in H.265.

Additionally, Smart265 and H.265+ are different encoding methods introduced by different manufacturers (essentially optimized algorithms). They are not universally compatible as non-standard compression methods. For instance, Hikvision calls it Smart265, while Uniview calls it Super265. Unless both the network camera and recorder are from the same manufacturer and support the same encoding method, the encoding will follow the H.265 standard.

3. Bitrate (also known as data stream), measured in bps (bits per second):
   • Bitrate refers to how much data is transmitted per second, and can be adjusted. A higher pixel camera typically supports a higher bitrate, leading to better image clarity but also larger storage space consumption.
   • Example: A bitrate of 2048 kbps (2 Mbps) means 2048/8 = 256 KB of storage per second.
4. Frames per second (fps):
   • Default is 25 fps.
5. Number of cameras.
6. Required storage days.

Example Calculation:

For a system with:

• One 32-channel NVR with 8 disk slots, supporting H.265 compression.
• 10 cameras with 2MP, supporting H.264, set at a bitrate of 5120 Kbps (5 Mbps).

Storage required for each camera:

• Storage per second: 10 * 5/8 = 6.25 MB
• Daily storage: 6.25 * 60 * 60 * 24 = 540,000 MB per day.

Since the cameras only support H.264, they will be encoded in H.264.

For another set of 10 cameras with 3MP, supporting H.265, set at 7168 Kbps (7 Mbps):

Storage required for each camera:

• Storage per second: 10 * 7/8 = 8.75 MB
• Daily storage: 8.75 * 60 * 60 * 24 / 2 = 378,000 MB per day (H.265 compression reduces storage by half compared to H.264).

For another set of 10 cameras with 3MP, supporting H.265+, set at 7168 Kbps (7 Mbps):

Storage required for each camera:

• Storage per second: 10 * 7/8 = 8.75 MB
• Daily storage: 8.75 * 60 * 60 * 24 / 2 / 2 = 189,000 MB per day (H.265+ compression theoretically reduces storage by half compared to H.265, but since the recorder only supports H.265, it cannot achieve this further reduction).

Total storage required for the day:

• Daily storage: 540,000 + 378,000 + 378,000 = 1,296,000 MB (1.296 TB)

For 10 days of storage:

• 10 days of storage: 10 * 1.3 TB = 13 TB

Thus, the required storage for 10 days is approximately 13 TB, which would require three 4 TB hard drives.

Note: The recorder usually uses dynamic bitrate, which adjusts automatically based on the algorithm. If necessary, the bitrate can be reduced to extend recording time without significantly impacting video quality.