From One Camera to a Site’s Terabytes

From One Camera to a Site’s Terabytes

Ada re-derives this chapter’s own numbers step by step, at full precision

foundations
math-foundations
calculation-audit
edge-fog
Ada ADA · CALCULATION AUDIT

From One Camera to a Site's Terabytes

The chapter puts one 4 Mbit/s camera at about 43 GB/day and a 50-camera site at roughly 2.1 TB/day — the numbers that decide whether the cloud path is even possible. An edge that emits one 200-byte event per second instead sends about 2,500x less. This audit carries the figures in full, from one camera to a site’s terabytes.

Companion to the chapter Edge-Fog Use Cases — every number here comes from that chapter.

See the relationship before changing it

The figure reads from left to right. The blue card is camera count. The middle card applies the page rule. The green card is raw site traffic. Walk the arrows once: set the input, apply the rule, then read the result with its unit.

Camera count changes raw site traffic An input card leads through the rule traffic = 43.2 GB/day x cameras / 1000 to the raw site traffic result. INPUT PAGE INPUT APPLY THE RULE predict calculate check units OUTPUT RESULT
Walk the arrows. Raw camera traffic grows linearly with the number of feeds.

Derive the baseline in four named moves

  1. 1

    Name the input. The chapter baseline is 50 cameras.

  2. 2

    Name the relationship. traffic = 43.2 GB/day x cameras / 1000

  3. 3

    Substitute with units. 43.2 x 50 / 1000 = 2.16 TB/day

  4. 4

    Read the result. Keep the unit beside the value. Use it only inside the technical boundary on this page.

Predict, then change camera count

Try Predict the direction of traffic = 43.2 GB/day x cameras / 1000. Test another camera count, then compare raw site traffic.

50 cameras
Chapter baseline
Raw site traffic

Observe Raw camera traffic grows linearly with the number of feeds. Reset camera count to 50 and compare raw site traffic.

Explain Raw camera traffic grows linearly with the number of feeds.

Check yourself

What should you do before trusting a moved-control result?
Answer: Predict its direction, apply the shown relationship, keep the units, and reset to the worked baseline.
What does this small model leave out?
Answer: Only camera count moves here. Field effects named in the technical boundary stay fixed.

Honesty note. This teaching model changes only camera count. It is not a field prediction.

TryThe chapter puts one 4 Mbit/s camera at about 43 GB/day and a 50 -camera site at roughly 2.1 TB/day — the numbers that decide whether the cloud path is even possible. Use Check derivation.
ObserveThe displayed ledger resolves 4 Mbit/s, 43 GB/day, 50, 2.1 TB/day, 200-byte at full precision. This audit carries the figures in full, from one camera to a site’s terabytes. Check derivation shows this.
ExplainCamera traffic scales linearly from 43.2 GB/day to 2.16 TB/day across 50 feeds; emitting 200-byte events instead of pixels cuts the per-camera path about 2,500x because the edge retains answers rather than frames. Check derivation confirms it.

Ada: This chapter claims one 4 Mbit/s camera is about 43 GB/day and a 50-camera site is roughly 2.1 TB/day. Those are the numbers that decide whether the cloud path is even possible, so let me carry them in full.

  • One camera. 4 Mbit/s x 86,400 s/day = 345,600 Mbit/day. Converting bits to bytes: 345,600 / 8 = 43,200 MB/day = 43.2 GB/day.
  • Fifty cameras. 43,200 MB x 50 = 2,160,000 MB/day = 2,160 GB/day = 2.16 TB/day — the “2.1 TB” the chapter quotes.
  • The event alternative (illustrative). If the edge instead emits one compact 200-byte event per second, that is 200 x 86,400 = 17,280,000 bytes/day = 17.28 MB/day per camera — about 43,200 / 17.28 = 2,500x less than the raw stream.

That 2,500x ratio is the whole argument for edge extraction: sending occupancy counts and shelf-gap events instead of pixels turns a site’s terabytes into megabytes while keeping the operational answer. The ratio only holds if the missed-event risk is measured against the retained sample, not assumed away.

Technical boundaries
The camera-volume model deliberately does not simulate variable-bit-rate codecs, packet headers, retransmissions, replicated storage, event bursts, or missed detections; it compares one constant raw stream with one illustrative fixed event cadence.

Work the audit first, then check the displayed derivation.

Every number above is taken from the chapter’s own material and re-derived step by step.