Bitrate is the setting that decides how many bits per second your security cameras send to your recorder or cloud. In plain English, it is the data budget for your video. Set it too low and motion turns blocky or smeared; set it correctly and faces, plates, and fine textures stay clear.
This guide explains what is bitrate for security camera systems, how it relates to frame rate, resolution, processing power, and compression (H.264 and H.265), and how to size data usage and storage with easy formulas and a ready-to-use table.
Two CCTV cameras with the same resolution can produce very different results because bitrate controls how much information survives encoding. When people move through the frame, when leaves or rain fill the scene, or when headlights flare at night, the encoder needs a larger data budget to preserve detail. Cameras with adequate bitrate capture faces and plates; cameras with starved bitrate drop into blur or blockiness. The required storage space is directly affected by each camera’s bitrate and how many days of recordings you keep, so choosing well balances quality, storage, and network performance.
An IP camera sends digital video over a network. IP camera bitrate is measured in Kbps or Mbps and tells you how much data the camera outputs every second. A higher bitrate usually means better image quality during motion and larger files. A lower bitrate means smaller files but a higher risk of visible artifacts. Manufacturers often ship sensible default bitrates that balance quality and performance, but you should still tune them for your scene and target retention.
Quick definitions
Bitrate is tightly linked to processing power inside the camera. The encoder must analyze each frame, compare it with the previous frame, and compress only what changed. The bit rate you choose determines whether the camera’s processor can keep up and maintain image quality. The right amount of processing power can be the difference between capturing a clear intruder face or ending up with an unusable blur. Cameras with the same resolution can record completely different footage because one has the headroom to encode motion cleanly while the other does not.
Frame rate and resolution shape the bitrate you need.
A camera with higher resolution requires higher bitrate for optimal results. Optimal frame rates for high-quality motion are commonly 20 to 30 FPS. If bandwidth or storage is tight, lowering frame rate reduces demand quickly. A 4K camera with a low bitrate can look worse than a correctly tuned 1080p camera, so match resolution, FPS, and bitrate as a set.
H 264 and H 265 are block-based, motion-compensated codecs. H.264 splits each image into small grids and updates only the parts that change. H 265 improves how those blocks are sized and predicted, which typically cuts bitrate by about half for similar quality. In practice:
If your NVR and mobile apps support H.265, prefer it. If you must mix older devices, test playback to ensure smooth scrubbing and export.
You can estimate data usage quickly with these formulas:
Data per hour (MB) = Bitrate (Mbps) × 3600 ÷ 8
Data per day (GB) = Bitrate (Mbps) × 10.8
Examples
Use motion-activated recording to reduce storage sharply in quiet areas. Continuous recording requires the highest bitrate and the most storage.
Total live and record bandwidth depends on the sum of your main streams and sub streams:
Total Bandwidth (Mbps) = Σ(Main stream bitrate) + Σ(Sub stream bitrate)
Busy scenes push higher bitrates, so plan headroom. A single 4K camera commonly needs 5 to 10 Mbps with efficient H.265, while a 1080p camera needs about 2.5 to 5 Mbps. If network capacity is limited, consider lowering FPS in static areas or enabling smart streaming features that trim bits without losing important detail.
This split lowers live viewing load while preserving evidence quality. Also check your NVR incoming bandwidth, which is the maximum total Mbps it can process from all cameras at once. Exceeding that rating causes dropped frames or degraded live view.
Use these values as a starting point, then test by day and night. Targets assume typical scenes. Raise values for high-motion views, lower for static areas.
| Resolution | FPS | H.264 Target | H.264 Max | H.265 Target | H.265 Max |
|---|---|---|---|---|---|
| 720p | 25 | 1.4 Mbps | 2.0 Mbps | 0.9 Mbps | 1.3 Mbps |
| 720p | 30 | 1.8 Mbps | 2.5 Mbps | 1.2 Mbps | 1.7 Mbps |
| 1080p | 25 | 2.0 Mbps | 4.0 Mbps | 1.2 Mbps | 2.5 Mbps |
| 1080p | 30 | 2.5 Mbps | 5.0 Mbps | 1.5 Mbps | 3.0 Mbps |
| 4MP | 25 | 3.2 Mbps | 6.7 Mbps | 1.8 Mbps | 3.5 Mbps |
| 4MP | 30 | 3.8 Mbps | 8.0 Mbps | 2.2 Mbps | 4.2 Mbps |
| 4K | 15 | 4.5 Mbps | 8.0 Mbps | 2.5 Mbps | 5.0 Mbps |
| 4K | 25–30 | 8–12 Mbps | 16 Mbps | 4–6 Mbps | 8–10 Mbps |
Notes
VBR and CBR are bitrate control modes:
For most surveillance, choose VBR with a sensible target and maximum. Use CBR only when a link must stay below a fixed ceiling.
Complex scenes like tree canopies, rain, crowds, and glittering water require more bitrate. Static hallways can run lower without losing evidence value. Camera placement that fills the frame with the subject allows you to keep bitrate modest while still reading faces or plates.
Use the daily estimate to size storage and uplinks. Remember that motion-activated recording reduces effective usage, sometimes by half or more. For busy entrances, plan near the continuous estimate. For quiet back-of-house areas, plan for much less.
Planning tips
For 1080p at 25–30 FPS, start at 2.5–5.0 Mbps on H.264 or 1.5–3.0 Mbps on H.265. For 4MP at 25–30 FPS, plan 3.2–8.0 Mbps on H.264 or 2.2–4.2 Mbps on H.265. For 4K, expect 8–12 Mbps on H.264 or 4–10 Mbps on H.265 depending on motion.
Yes. Higher bitrate settings lead to better video quality, especially during motion. Too low and you lose detail. The correct value depends on resolution, FPS, codec, and scene complexity.
VBR for most deployments because it adapts to the scene. CBR only when a strict cap is mandatory.
For local recording on an NVR, 300 Mbps is plenty for many systems. For remote viewing, the site’s upload speed is the limit, so rely on sub streams and pull main streams only when needed.
Place cameras where people make decisions: doors, gates, tills, and chokepoints. Use higher bitrates in high-traffic zones where fine detail matters and lower bitrates in static spaces. Adjustable bitrate settings let you tailor quality to surveillance needs, and smart streaming can optimize bandwidth without sacrificing evidence.
| Use Case | Resolution | FPS | Codec | Target Bitrate | Max Bitrate |
|---|---|---|---|---|---|
| Front door faces | 1080p | 20–25 | H.265 | 1.8–2.2 Mbps | 3.0 Mbps |
| Reception counter | 4MP | 25–30 | H.265 | 3.0–3.8 Mbps | 5.0 Mbps |
| Vehicle exit plates | 1080p | 25–30 | H.265 | 2.5–3.0 Mbps | 4.0 Mbps |
| Warehouse aisle | 1080p | 15–20 | H.265 | 1.2–1.8 Mbps | 2.5 Mbps |
| Wide car park | 4K | 15–20 | H.265 | 4–6 Mbps | 8–10 Mbps |
| Quiet corridor | 720p | 15 | H.265 | 0.7–1.0 Mbps | 1.5 Mbps |
Adjust after a night test. If you see dynamic scenes with complex textures, increase the target by 10 to 25 percent.
Optimising bitrate is always a balance of video quality, storage capacity, and network headroom. Start from conservative targets, then tune downward only if your review tests still look clean.
Not sure what bitrate you need? We can help. Bitrate ties image quality, bandwidth, and storage together, so set it with intent: match it to your resolution and frame rate, choose the best codec your stack supports, use the main stream for recording and a sub stream for smooth live views, and test by day and night.
Spend the bits in high-motion, high-detail zones, and save them in quiet spaces. With Castle Security, you don’t have to sweat the tech; we’ll tune your IP camera bitrate, resolution, and H.265 settings in plain English so you get clear, reliable footage without wasting capacity.
