Defensive labs About 1 min read

Video bandwidth and storage calculation

Calculate a fictional video recording budget. State the bitrate, retention, overhead and failure capacity assumptions so the result can be checked.

Sources and scopeSource record 25 August 2026

Technical source record: 25 August 2026. Check the linked documentation for current product requirements.

Offline research and planning only; product or deployment acceptance belongs to separately governed environment validation.

Verification and testing

Overview#

Lab class: Offline calculation

Core calculation#

For a constant average stream bitrate B in bits/second over duration T seconds:

text
payload bytes = B × T ÷ 8
usable storage = payload bytes × overhead factor × resilience factor

Example inputs should be synthetic. A 4 Mbit/s average stream over one day produces about 43.2 GB decimal before container/filesystem/index overhead, retention headroom, replication, failures, exports and other streams.

Required scenario variables#

  • codec/profile/level, resolution, frame rate and GOP;
  • constant/variable bitrate controls and measured scene range;
  • audio, metadata and secondary streams;
  • continuous versus event recording and pre/post event duration;
  • transport/container/database/index overhead;
  • camera count and synchronised peak behaviour;
  • edge catch up/retrieval after outage;
  • RAID/erasure coding, replication, hot spare and reserved free space;
  • retention/deletion policy, evidence holds and export work area;
  • network multicast/unicast fanout and client/analytics copies;
  • failure/rebuild throughput and maintenance margin.

Exercise#

Build nominal, busy scene peak, outage catch up, and degraded storage scenarios from synthetic low/nominal/high inputs. State whether units are decimal GB/TB or binary GiB/TiB and preserve the range rather than collapsing variability into one value. Comparison with field measurements belongs to separately governed environment validation after privacy review.

Evidence checklist#

  • Synthetic input set, units, source assumptions, and calculation method recorded
  • Nominal, busy scene peak, outage catch up, and degraded storage scenarios calculated
  • Video, audio, metadata, secondary streams, and synchronised peak behaviour included
  • Container, filesystem, index, reserved space, replication, and resilience overhead included
  • Retention, evidence holds, exports, rebuild throughput, and maintenance margin represented
  • Network fanout and edge catch up separated from storage consumption
  • Decimal and binary units labelled and uncertainty/ranges preserved

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