Appendix B  HDD Capacity Calculation 
 
Calculate total capacity needed by each DVR according to video recording (video 
recording type and video file storage time).   
Step  1:  According  to  Formula  (1)  to  calculate  storage  capacity 
  that is  the 
capacity of each channel needed for every hour, unit Mbyte.   
  means the bit rate, unit Kbit/s 
Step 2: After video time requirement is confirmed, according to Formula (2) to 
calculate the storage capacity
, which is storage of each channel needed unit Mbyte.   
  means the recording time for each day (hour) 
  means  number  of  days  for  which  the  video 
shall be kept 
Step 3: According to Formula (3) to calculate total capacity (accumulation) 
 
that is needed for all channels in the DVR during scheduled video recording.   
means total number of channels in one 
DVR   
Step  4:  According  to  Formula  (4)  to  calculate  total  capacity  (accumulation) 
that is needed for all channels in DVR during alarm video recording (including 
motion detection).   
×a%                                                    (4) 
In the formula:a% means alarm occurrence rate