Size a Frigate NVR by Bitrate, Not Megapixels

By LK Wood IV · Published 2026-09-07 · St. Louis County, MO

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Reolink’s RLC-520A is a 5MP camera. Its RLC-811A is 4K — 3840×2160 against the 520A’s 2560×1920, about seventy percent more pixels. Reolink’s own spec pages give both the same mainstream default: 6144 kbps.

Same default, same file size, same drive. The megapixel number on the box predicts nothing about your storage bill.

This page is about picking the right input. For which machine to buy once you have the number, see best hardware for Frigate NVR.

Frigate copies the stream, so the camera sets the size

Frigate’s recording documentation states that recordings are “written directly from your camera stream without re-encoding.” Nothing in Frigate compresses your footage. Whatever bitrate the camera emits is what lands on the disk, byte for byte.

That collapses the whole storage question to one multiplication. One megabit per second of continuous recording is 86,400 megabits a day, which is 10.8 GB/day. Everything else — resolution, frame rate, codec — matters only because it moves the bitrate.

Here is the Reolink mainstream range, converted:

Bitrate ranges from the Reolink RLC-520A and RLC-811A specification pages, read 2026-09-07. Continuous recording, decimal gigabytes.

Read the two ends of that column. The setting inside one camera moves your storage by a factor of eight. The megapixel step between the two cameras moves it by zero. You are shopping the wrong variable.

Reolink’s substreams are capped at 512 kbps against the mainstream’s 8192 kbps, per its bandwidth support article — a sixteen-fold gap that matters later.

Put your own cameras’ numbers into the Frigate NVR storage calculator. It takes a known bitrate directly.

What megapixels actually cost: the detect stream

Resolution is not free. It just does not bill you where people look.

Frigate’s camera setup guide describes the detect stream as “the only stream that Frigate will decode for processing,” and the record stream as “the resolution you wish to store for reference.” Two different streams, two different budgets. The 4K stream goes to disk untouched. The substream is what gets decoded, buffered and inspected.

You can see the split cleanly in shared memory. Frigate’s installation docs give a per-camera minimum of (width × height × 1.5 × 20 + 270480) / 1048576 MB, computed on the detect resolution, plus up to 40 MB for logs:

Frigate’s own worked example prints 66.63 MB for a single 1280×720 camera including logs, which is 26.63 plus the 40 MB log allowance — the arithmetic above reproduces it exactly.

Detecting at 4K costs nearly nine times the shared memory of detecting at 720p. Recording at 4K costs none of it. Run a 1280×720 detect substream and record the main stream at whatever resolution you paid for. Frigate’s guide asks that the detect and record streams share an aspect ratio, for the sake of its UI.

The detector budget is frames, not cameras

The third budget is inference, and Frigate publishes the arithmetic for it. From the recommended hardware page: “With an inference speed of 10, your Coral will top out at 1000/10=100, or 100 frames per second.”

So a detector’s ceiling is 1000 divided by its inference time in milliseconds, and your demand is camera count times detect frame rate. Frigate’s camera guide recommends 5 fps for detection, rising toward 10 fps only for very fast-moving objects. At 5 fps, a detector rated 100 fps covers twenty cameras’ worth of detection in the worst case where every camera is triggering at once — and Frigate gates object detection behind motion detection, so the realistic load sits well under that.

Detect frame rate is the lever here. Record resolution appears nowhere in it.

Frigate’s object detector docs note that “when using many cameras one detector may not be enough to keep up” and that “multiple detectors can be defined assuming GPU resources are available.” If your arithmetic lands close to the ceiling, that is the escape hatch — not a bigger drive.

The fourth budget is watts

Cameras draw power, and the megapixel number predicts that no better than it predicts storage.

Reolink lists the fixed 4K RLC-811A at “<12W” on “IEEE 802.3af, 48V active.” The 4K RLC-823A PTZ is listed at “DC 12.0V⎓2A, <24W” and requires “IEEE 802.3at.” Identical resolution, identical 6144 kbps default, double the power class.

Six fixed cameras plus two PTZs is roughly 120 W of rated device draw before cable loss and headroom. Plenty of eight-port PoE switches do not supply that, because “eight PoE ports” describes connectors rather than a power budget. Add the rated watts, add the run length, add a margin, and buy on the total — the PoE budget calculator does exactly that.

Getting your real number off the camera

Reolink’s support article says to open Settings → Stream and click Maximum Bitrate. Every other vendor has the equivalent screen. That number, not the marketing resolution, is your sizing input.

What the number means depends on the control mode, and Axis’s bitrate control white paper is the clearest published account of the difference. Variable bitrate has the benefit of “constant, uncompromised video quality,” but its drawback is that storage needs “may be unpredictable,” because “motion or other events in the scene can cause the stream size and bitrate to increase significantly.” Maximum bitrate “guarantees that the bitrate stays below a set limit regardless of video scene complexity” — by compressing harder, “with no consideration of the effects on image quality.”

Set a maximum bitrate. An NVR that overruns its disk in week three is a worse outcome than a busy frame that softens, and a cap makes the storage calculation deterministic instead of a guess about how much your driveway moves.

Codec is the other lever, and it is a real one. Catellier and Pinson’s subjective study for NTIA/ITS describes H.265/HEVC as “developed to be roughly twice as efficient as H.264/AVC — meaning H.265/HEVC could deliver the same quality as H.264/AVC using roughly half the bitrate.” The RLC-811A lists “H.264, H.265”; the older RLC-520A lists H.264 only. At a shared 6144 kbps default, the H.265 camera is the one giving you more picture for the same disk.

Axis makes the same point commercially with Zipstream, which it says “lowers bandwidth and storage requirements by an average of 50% or more when compared to standard compression” by adapting “based on scene motion, scene content, ambient light level, and settings.” Note what is missing from that list: resolution. Axis ships it on cameras as ordinary as the 1080p P3265-LVE.

Where a bitrate table stops working

Equal bitrate is not equal quality. In the same NTIA study, “for all 20 scenes coded with H.265/HEVC at 4 Mbps mean opinion scores span 38% of the subjective scale, which indicates the importance of scene selection.” Nearly two fifths of the quality range, at one fixed bitrate, purely from what was in front of the lens.

So the storage arithmetic transfers between installations and the quality does not. A quiet indoor hallway at 4096 kbps and a wind-blown tree line at 4096 kbps write the same gigabytes and look nothing alike. Set the cap, record for two days, look at your own worst camera, and adjust that one. Do not adjust all of them because one scene is busy.

Buy the 10TB SkyHawk AI and cap the cameras at 4096 kbps

Four 4K cameras, continuous, 30 days retained, capped at 4096 kbps: 5.31 TB. Left at the 6144 kbps default: 7.96 TB, which does not fit an 8TB drive with any usable headroom.

That is the whole buying decision, and it is a camera setting rather than a hardware problem.

The 10TB is the pick. It absorbs the 6144 kbps default without a resize, leaves room for a fifth camera, and in this feed it undercuts the model-named 8TB SkyHawk row (ST8000VX004, $514.10 ) by $64.10 for two extra terabytes. Buy the 4TB only for a 14-day motion-only build.

Those prices come from a feed deposited 2026-08-17 and drive pricing moves weekly. Open the link before you spend anything.

Do not buy a bigger NVR box because you bought 4K cameras. Storage is set by the bitrate cap, detection runs on a 720p substream, and shared memory follows the substream too. The 4K upgrade is close to free on the Frigate machine — what it costs you is camera price and, if you raise the cap to make 4K look like 4K, disk. Which box to buy is settled in best hardware for Frigate NVR, and the drive class question in best NAS hard drives.

The four numbers, in order

1. Bitrate cap per camera, from the camera’s own stream page. Multiply by 10.8 GB per Mbps per day, then by retention. → storage calculator
2. Detect substream resolution, 1280×720 unless objects are genuinely tiny. Run Frigate’s shm formula on it.
3. Detect frame rate, 5 fps, times camera count, against 1000 ÷ your detector’s inference milliseconds.
4. Rated watts per camera, summed, plus cable loss and headroom. → PoE budget calculator

None of those four takes megapixels as an input. That is the point.

Sources

• Frigate documentation, opened 2026-09-07: recording (streams written without re-encoding), camera setup (detect is the only decoded stream), installation (shm formula and worked example), recommended hardware (inference-speed arithmetic), planning a new installation, motion detection, object detectors
• Reolink specification pages, opened 2026-09-07: RLC-520A, RLC-811A, RLC-823A, and the bandwidth and finding your bitrate support articles
• Axis Communications white papers: bitrate control for IP video, Zipstream technology; product specifications for the AXIS P3265-LVE
• A. A. Catellier and M. H. Pinson, Characterization of the HEVC Coding Efficiency Advance Using 20 Scenes, ITU-T Rec. P.913 Compliant Subjective Methods, VQM, and PSNR, NTIA/ITS, December 2015
• Drive prices: Newegg product feed via Rakuten (MID 44583), deposited 2026-08-17, lowest in-stock USD row per listing