01
Define the recording before counting terabytes.
List every view and its actual recorded stream. A mosaic preview is not necessarily the archived stream. Record schedules, active periods, playback needs and authorised viewers/exporters. A day count alone is neither a complete requirement nor permission to retain footage.
Separate groups with different parameters. A continuously recorded entrance and a scheduled area should not share an unexplained average. Mark values as measured, documented or assumed. The integrator can then correct a line without rebuilding the quotation from hidden assumptions.
02
Four quantities, four checks.
Scroll the table horizontally to compare all three columns.
| Quantity | What it describes | What it does not prove |
|---|---|---|
| Stream bitrate | Data per second with an identified control mode. | A limit is not necessarily an average or guaranteed quality. |
| Recorded time | Hours per day and calculation period for each group. | Event mode does not establish a constant activity ratio. |
| Usable capacity | Space actually available to the configured service. | Summed nominal capacities are not usable capacity. |
| Verified playback | A retrieved, readable clip exportable under intended permissions. | An installed drive or green indicator does not prove this chain. |
03
Collect the inputs that change the result.
Streams and activity
Record codec, resolution, frame rate, bitrate and their sources. Scene and settings can vary bitrate; a restrictive limit can degrade detail. Compare quiet and representative busy periods. Do not promise codec or brand savings without case-specific evidence.
Schedules and events
Write each group’s schedule and any pre/post-event recording. If event activity is unknown, retain the unknown and an explicit cautious assumption. Do not equate shop opening hours with recording hours without confirmation.
Storage architecture
Specify usable capacity, system space, audio, metadata and design reserve. Check supported media, stream limits and actual recorder functions. Redundancy can consume capacity; it does not replace a backup/export plan for material requiring preservation.
Operating rules
Name who validates permitted retention, monitors faults and authorises exports. Record full-storage and recovery behaviour. Check actual retention/deletion settings; available space is not a reason to keep footage longer.
04
Two groups, one explicit total, no false guarantee.
ILLUSTRATIVE EXAMPLE
Fictional constant-bitrate case: A has 4 cameras at 4 Mbit/s, 24 h/day; B has 2 at 2 Mbit/s, 12 h/day. Both use an arbitrary 7-day period. These are not recommended site settings.
Calculate each group
The raw formula gives 1209.6 decimal GB for A and 151.2 GB for B. It converts bits to bytes and multiplies by time. Calculate groups separately rather than hiding their schedules in an unexplained average.
Add comparable volumes
The total is 1360.8 decimal GB, or 1.3608 TB. Audio, metadata, system space, redundancy and reserve are excluded. Do not mix decimal and binary units in the quotation.
Return to usable capacity
A drive labelled 2 TB does not validate the brief. Compare the completed requirement with the chosen architecture’s usable capacity and supported streams. Verify retained playback separately; arithmetic is not a retention test.
The calculation assumes constant bitrates. It does not simulate peaks, events, failures or hardware functions, and determines no legal retention period.
05
Verify the service, not just free space.
Recording and timestamps
Retrieve every view in an authorised test sequence and check timestamps and expected continuity. Distinguish no scene activity, no trigger and recording failure. Keep results and reservations, not just drive health indicators.
Access and export
An authorised user checks playback, export and exported-file readability on the intended workstation. Unauthorised users must not gain access. Passwords and site footage do not belong in a shared commercial bill of materials.
Faults and revision
Name alert recipients and verify delivery through an authorised procedure. Recalculate after adding views or changing quality. A smaller configuration is acceptable only if the required task and agreed rules remain satisfied.
06
Test your assumptions, then complete the brief.
The calculator starts with group A. Change one group at a time and keep its record before adding volumes. Empty or out-of-range input hides the result rather than becoming zero. Include assumptions and exclusions in the quotation brief. Inovexia helps identify documented references; usable capacity and final settings require project validation.
07
Avoid storage-sizing shortcuts.
Do megapixels directly determine storage?
No. You need the chosen bitrate, schedule, period and exclusions from raw volume. Resolution alone does not describe recorded quantity.
Does event recording always halve storage?
No. Activity, settings and pre/post-event recording matter. Without representative observation, keep the ratio unknown and document your assumption.
Does H.265 guarantee a specific saving over H.264?
Not from the label alone. Compare supported configurations at equivalent useful detail and observed bitrate. No saving percentage is promised here.
Does RAID replace backup?
No. Possible fault tolerance does not address every deletion, configuration or access risk. Define preservation and backup/export procedures separately.
Should the example’s seven days be used on site?
No. It is an arbitrary teaching input, not legal advice. The responsible party confirms applicable retention and conditions before configuration.
Technical sources
External reading references. These documents explain principles; they do not certify catalogue products or their combination.
- Quality with a purposeAxis Communications · Sources consulted on
- Bitrate control for IP videoAxis Communications · Sources consulted on