Multi-Stream Profiles: How CCTV Cameras Send Different Bitrates to Different Viewers

Most modern IP cameras aren’t actually sending just one video stream — they’re simultaneously generating two or three differently-configured streams from the same sensor, each sized for a different destination and purpose, and network bandwidth sizing needs to account for all of them, not just the one used for recording.

Why one camera sends multiple streams

A single camera sensor can be encoded into multiple output streams simultaneously, each with independently configured resolution, bitrate, and frame rate — most commonly a main stream (full quality, used for local NVR recording where storage and local network bandwidth are typically ample) and a sub-stream (meaningfully reduced resolution and bitrate, optimized for remote viewing on a mobile app or over a limited-bandwidth internet connection). Some cameras support a third profile for additional flexibility, but the main-stream/sub-stream split is the most common and most practically important pattern.

Why the sub-stream needs to be so much smaller

A phone’s screen is dramatically smaller than a monitor reviewing full-resolution recorded footage, and a mobile data connection or home internet upload connection typically has far less available bandwidth than a local wired NVR connection — meaning a sub-stream sized at full main-stream bitrate would be genuinely wasteful (more data than the viewing device or connection can meaningfully use) and often outright impractical (exceeding available mobile bandwidth entirely). A sub-stream commonly runs at a small fraction of the main stream’s bitrate — reduced resolution, sometimes reduced frame rate too — sized specifically for its actual viewing context rather than matching the main stream’s recording-quality target.

What this means for network bandwidth sizing

This is exactly why network bandwidth sizing needs to distinguish between two genuinely different bandwidth requirements: the local network carrying camera-to-NVR traffic needs to handle the sum of all main stream bitrates (the figure the Network Bandwidth Calculator is typically used for), while the internet uplink supporting remote mobile viewing needs to handle the sum of sub-stream bitrates for however many cameras are being actively remotely viewed simultaneously — a substantially smaller figure, but a real, separate bandwidth requirement that’s easy to overlook if only the main-stream recording bandwidth was accounted for.

Sizing both bandwidth requirements correctly

Requirement	What to sum	Typical relative size
Local network (camera to NVR)	All cameras’ main stream bitrates	Larger — this is what the base bandwidth calculation covers
Internet uplink (remote viewing)	Sub-stream bitrates for cameras being actively remote-viewed	Smaller, but genuinely separate

A common oversight is sizing the local network correctly using main-stream bitrates, then assuming the same network handles remote viewing without any additional consideration — remote viewing over the internet uplink draws on a completely separate bandwidth budget (the site’s internet upload capacity), which needs its own sizing check using sub-stream bitrates and a realistic assumption about how many cameras might be remotely viewed simultaneously.

A worked example distinguishing the two

For an 8-camera installation with 4096 Kbps main streams and 512 Kbps sub-streams: local network bandwidth needs to handle 8 × 4096 = 32.77 Mbps (main streams, for NVR recording). If up to 4 cameras might be remotely viewed simultaneously via mobile app, internet uplink needs to handle only 4 × 512 = 2.05 Mbps of sub-stream traffic — a meaningfully smaller, genuinely separate figure from the local network’s requirement, and one that needs checking against the site’s actual internet upload capacity specifically.

Configuring stream profiles appropriately

Most camera configuration interfaces expose main-stream and sub-stream settings independently, letting you tune each for its actual purpose — a full-resolution, higher-bitrate main stream for local recording where bandwidth and storage are relatively ample, and a deliberately smaller sub-stream sized appropriately for realistic mobile viewing conditions, rather than leaving default settings unchecked and potentially over- or under-provisioned for either use case.

FAQ

Do all IP cameras support multi-stream profiles? Most modern IP cameras do, though the number of simultaneous stream profiles and configuration flexibility varies by manufacturer and model — checking a specific camera’s specification sheet confirms its actual multi-stream capability.

Should the Network Bandwidth Calculator use main-stream or sub-stream bitrate? For sizing the local network handling NVR recording, use main-stream bitrate. For sizing internet uplink capacity for remote viewing specifically, use sub-stream bitrate for the number of cameras likely to be viewed simultaneously.

Does using a sub-stream reduce recorded footage quality? No — the sub-stream is typically used only for live remote viewing, while the main stream (full quality) is what’s actually recorded to the NVR, so recorded footage quality is unaffected by sub-stream settings.

How many cameras are typically remote-viewed at once via mobile app? This varies significantly by use case and user behavior — a realistic assumption based on your specific installation’s actual remote-viewing patterns is more useful than a generic industry figure for sizing internet uplink needs.

Can I disable the sub-stream if I never use remote mobile viewing? Often yes, which can reduce the camera’s total processing and encoding load slightly, though most installations retain sub-stream capability for at least occasional remote access flexibility.

Does a third stream profile (if supported) serve a different purpose than main/sub? When available, a third profile is often used for a specific additional purpose (like a very low-bitrate stream for basic motion detection analysis) rather than direct human viewing — checking your specific camera’s documentation clarifies what any additional profile is actually intended for.

Whether a stream is triggered by motion or runs continuously affects the main stream’s real-world bandwidth pattern independent of the sub-stream question covered here.