The Evolution of Video Quality and Storage Needs Historically, CCTV systems recorded uncompressed video in low resolution. However, the modern user's preference leans towards having video archives in 720p and 1080p, requiring substantial disk space. The advent of h264/265 compression has allowed for space conservation, but it also places increased load on the processor or graphics card for video processing.
The Dilemma of Continuous Recording Continuous recording becomes crucial, especially in scenarios where constant movement occurs within the frame, enabling the identification of actions after their occurrence. This is particularly essential in public places like airports, busy streets, shopping malls, and highways. However, in environments with minimal movement, continuous recording may not be as crucial, and recording can be triggered by the presence of a human or animal. For example, recording in an elevator lobby makes sense when someone enters, or if there are unexpected visitors in a store at night. In moments of inactivity, recording in time-lapse mode can save disk space/cloud server space while maintaining continuous documentation.
Calculating Storage Needs: 1080p vs 4k Let's exemplify the substantial storage requirements by calculating the disk space needed for continuous recording of 1080p and 4k resolutions at 30 frames per second for one year. The feasibility of recording in 4k, especially when dozens of surveillance cameras are installed, is also worth exploring.
Calculations for Storage Requirements Let's consider the following variables:
- Bitrate: 1080p - 16 Mbps; 4k - 64 Mbps
- Number of seconds in a year: 60×60×24×36560×60×24×365
The storage requirement (in GB) can be calculated as:
Storage Requirement (GB)=(Bitrate (Mbps)×Number of Seconds in a Year)/(8×1024)
Now, let's calculate the storage requirements for 1080p and 4k resolutions. For continuous recording at 30 frames per second for one year, a 1080p camera would require approximately 61,594 GB (or roughly 61.6 TB) of storage, whereas a 4k camera would necessitate about 246,375 GB (or approximately 246.4 TB) of storage. The quadruple increase in storage requirements when transitioning from 1080p to 4k illustrates the substantial storage demands of higher resolution recordings, raising questions about the practicality of 4k recordings when multiple surveillance cameras are in operation.