Appendix
I
Storage Capacity Calculation
TEC00-015-A01
DSR
Installation Guide
Page 27 of 32
Appendix I Storage Capacity Calculation
A common question about the storage capacity
How can I setup recording with 16 and 8-camera inputs for continuous 24 hours, 48 hours and 72 hours of
recording? Can I retain 7 days of recording before overwriting it? What hard disk upgrade is needed so
that it can do 7-day recording before overwriting?
The recording capacity of DSR
DSR use advanced wavelet compression technology for real time video compression.
The average compressed frame size of a CIF resolution image (384x288 PAL, 320x240
NTSC) is about 8Kbytes. And the average frame size of a QCIF resolution image
(192x144 PAL, 160x120 NTSC) is about 3 Kbytes.
The maximum frame rate is 30 fps for NTSC system, and is 25 fps for PAL system.
However, when frame rate above 8 fps, the video will perform as real time like video.
The basic DSR configuration provides a 6GB hard disk for video recording.
Following is the equation that can be used to estimate the recording time of DSR.
Recording time (hr) = storage_size /(frame_size*fps*3600*no_of_camera)
Where storage_size is the storage size of the hard disk installed in the unit, frame_size is
the average compressed frame size for individual image, fps is the frame per second and
no_of_camera is the number of camera that are recorded.
Example
:
When recording a camera in CIF resolution and real time recording at 25 fps, the 6GB
hard disk can provide about 8 hours of recording.
