in order to achieve efficient video transmission, it is important to evaluate your bandwidth requirements before setting up an IP surveillance system using cctv storage calculator.
Bandwidth requirements in cctv storage calculator vary with the following factors :
- Resolution: the higher the resolution, the more bandwidth is required
- Complexity of the scene: the more complicated the scene, the more bandwidth is required
- Compression type: the lower compression ratio, the more bandwidth is required
- Image quality: the higher image quality, the more bandwidth is required
- Frame rate: the higher frame rate, the more bandwidth is required
Storage
Besides bandwidth assessment, your storage space is also required to be evaluated, especially with megapixel images.
The following factors must be taken into account when assessing storage demand :
- The number of cameras deployed
- Recording time
- Recording criteria, such as constant, scheduled or event-triggered recording
- Other factors such as codec, image quality and frame rate
Storage Media
- Internal buffer
A network camera is equipped with an embedded flash memory or DRAM as a buffer zone that enables temporary storage of pre- and post-event video images. Images are stored in the buffer zone for a short period of time before being transmitted to the back-end recording platform.
- External memory card
CF, SD and SDHC cards are three main external memory types. They are designed for pre- and post-event storage and data portability.
- DAS (Direct Attached Storage)
Images are transmitted from a camera to a host PC via Ethernet cables and stored directly in the hard disk drive of the PC. DAS is aimed to enable storage and playback on the same PC and is mainly used by small- or mediumsized businesses.
- NAS (Network Attached Storage)
mages are transmitted to a purpose-built NAS server via Ethernet cables for storage. NAS allows storage and playback on different platforms and is especially suitable for enterprises that need to access and share large volume data
- SAN (Storage Area Network)
mages are sent to a purpose-built SAN server via an exclusive fiber optic cable for storage. As with NAS, storage and playback of images can be performed on different platforms, but SAN further reduces Ethernet bandwidth usage and offers a faster transfer rate.
Redundancy
n a bid to avoid significant losses from network downtime and hard disk drive cracks, it is highly recommended to plan a redundancy solution ahead, such as using back-up cables or RAID structure.