Estimating Storage Requirements for a Recording
Estimating Storage per Recording Hour
You need to know video and audio bit rates configured in your Extron SMP 351. For these
examples, the calculations assume that the bit rates remain constant during the recording;
if you are using VBR (variable bit rate, which is the default) then the actual bit rates will be
slightly lower than this estimate.
To estimate storage per recording hour:
1.
Find the SMP 351 video bit rate and audio bit rate, which are in kbps (kilobits per
second)(see
Configure Video Encoding
on page 94).
2.
Insert those bit rates into the following equation:
[(video bit rate + audio bit rate) *3600 seconds per hour] / 8 = x kBph (kilobytes per
hour)
3.
Use the kBph value to calculate MBph and GBph:
•
(x kBph / 1024) = y MBph (megabytes per hour)
•
(x kBph / 1048576) = z GBph (gigabytes per hour)
Example:
Using the default “720p High” encoder preset, with
•
Video bit rate = 5000 kbps
•
Audio bit rate = 192 kbps
For a 1-hour recording (3600 seconds),
•
(5000 + 192 * 3600) / 8 = 2336400 kBph
•
2336400 kBph / 1024 = 2281.64 MBph
•
2336400 kBph / 1048576 = 2.23 GBph
For the default encoder presets of an SMP 351, the following are the estimated storage
requirements for each hour of recording:
Estimated Storage Requirements
Encoder
Preset
Video bit rate
(kbps)
Audio bit
rate (kbps)
MB per hour
GB per hour
1080p High
8000
320
3656.25
3.57
1080p Low
6000
128
2692.97
2.63
720p High
5000
192
2281.64
2.23
720p Low
3000
128
1374.61
1.34
480p High
2500
128
1154.88
1.13
480p Low
1500
80
694.34
0.68
VGA High
3500
128
1594.34
1.56
VGA Low
2500
128
1154.88
1.13
SMP 351 max.
rates
10000
320
4535.16
4.43
SMP 351 min.
rates
200
80
123.05
0.12
NOTE:
If you choose from one of several encoding rates, do the above calculation
for each of the possible rates. You will also need to estimate how often each of the
encoding rates is selected.
SMP 351 • Reference Information
204