Calculating the required net storage capacity can be done using the following formula:
Daily storage capacity = (“Average number of calls per day”) ´ (“Average call audio size”)
The average call audio size can be calculated using the following formula:
Average call audio size = (The audio compression in Kbytes/sec) ´ (Average call length in Seconds)
For Example, in a site using ACA 5.6 Kbit/sec compression for recording by, having an average call length of 3 minutes, the average call audio size will be 3´60 (seconds) ´ 5.6 Kbit/sec = 1008 Kbits = 126 Kbytes
(8 bits = 1 bytes)
Referring to the storage capacity per day, if this site has 20,000 calls per day and is required to store them all, then the average daily net storage capacity required will be 20,000 calls 126 Kbytes (based on ACA 5.6 Kbit/s compression) = 2.4 GB.
Note: the figures above refer to storing the audio in a proprierty format. Saving the audio as PCM WAV files multiplies the net storage required by 4 compared to ADPCM 16 compression and by more than 11 compared to ACA 5.6 Kb/sec (as the audio compression used when storing in WAV format is 64 Kbit/sec).
Required Network Bandwidth
Calculating the required average network bandwidth can be done using the following formula:
Required network bandwidth = amount of data to be archived / the time used for archiving.
For example, if the data to be archived is 20GB in size and it should take 24 hours to complete the archiving procedure then the required average network bandwidth is 20GB/24hour = 0.83 GB/hour = 242.4 Kbytes/sec.