gCMOB Video Quality Guide: Main Stream, Sub Stream and Clearer Pictures

1

Introduction

When a gCMOB picture looks soft or falls into blocks exactly when someone walks past, users tend to blame the camera. Most of the time the camera is fine and the stream choice is not: the app shows a lighter sub stream by default on many setups, and compression shows its limits on movement first.

This guide explains the two streams, what resolution and bitrate really control, and how to get the clearest picture your system can honestly deliver for both live view and playback. The gCMOB Download for Android - CCTV Camera Monitoring App Guide page itself collects the download, the requirements and the FAQs in one place.

2

Main Stream and Sub Stream, Side by Side

Every channel effectively carries two feeds. The main stream is what the recorder stores at full quality: highest resolution and bitrate, intended for evidence. The sub stream is a reduced companion feed created for remote viewing on limited connections.

Knowing which one you are watching explains almost every quality surprise. A face that is unrecognizable on sub stream may be perfectly clear when you switch the same moment to main stream:

• Main stream is the recorded quality
• Sub stream is the travel-friendly feed
• Same camera, two very different pictures
• Switch streams before judging a camera
• Playback can also use either stream

3

Resolution, Bitrate, and Frame Rate in Plain Terms

Resolution is picture size in pixels; bitrate is how much data per second the encoder may spend describing the picture; frame rate is how many pictures per second. High resolution with low bitrate produces the classic failure: a still scene looks sharp, then movement smears into blocks because the data budget cannot describe the change.

These values are set on the recorder per stream. Raising sub-stream bitrate modestly is often the single best quality upgrade for app viewing:

• Resolution is size, bitrate is detail budget
• Movement exposes low bitrate first
• Frame rate affects motion smoothness
• Encoder settings live on the recorder
• Small sub-stream increases help a lot

4

Why Pictures Pixelate When Things Move

Video compression saves data by describing differences between frames. A quiet corridor barely changes, so even a light stream looks clean. A person crossing quickly changes many pixels at once, and a starved bitrate responds with blocks and blur until the scene settles.

Busy scenes, rain, and foliage in wind are permanently high-change, which is why outdoor cameras need more bitrate than indoor ones at the same resolution:

• Compression describes change, not scenes
• Movement spends the detail budget
• Outdoor scenes are always busy
• Night IR noise also consumes bitrate
• The fix is bitrate or stream choice

5

Getting the Clearest Live View in the App

For checking an event or identifying a person, switch the channel to main stream, view it full-screen in landscape, and let the stream settle a second before judging. For casual monitoring, sub stream in a grid is the right economy.

1. 1

   Open the channel in single view.

2. 2

   Switch the stream setting to main stream.

3. 3

   Rotate to landscape full-screen.

4. 4

   Pause on the moment instead of zooming a moving picture.

5. 5

   Use snapshots on main stream for stills you may share.

6

Recorder-Side Settings Worth Adjusting

If you manage the recorder, three adjustments matter for app users: raise the sub-stream bitrate within your upload limits, set the main stream to constant quality where the model supports it, and match frame rates sensibly rather than maximizing everything.

Change one value at a time and watch the app result. Recorder menus differ by model, so note original values before experimenting:

• Sub-stream bitrate tuned to your upload
• Avoid maximum everything by default
• Note original values before changes
• Test results inside gCMOB
• Installer help is worthwhile for big systems

7

Judging Quality Fairly: A Simple Test Routine

Quality arguments end with a fair test. Stand a person at the distance where identification matters, in day and again at night, and capture snapshots on both streams. Judge faces and plates in those stills, not impressions from a moving picture.

That five-minute routine tells you whether to raise bitrate, move a camera, or accept that a position simply needs a closer camera, and it gives you before-and-after proof for any change:

• Test at identification distance
• Day and night snapshots
• Judge stills, not moving video
• Results decide the real fix
• Keep snapshots as baselines

8

When the Camera Itself Is the Limit

Sometimes settings are innocent and the hardware is simply old: a low-resolution analog camera will never produce identification detail at distance, whatever the stream settings claim.

In that case the honest upgrade is one better camera in the one position that matters, usually the main entrance, rather than replacing a whole working system:

• Old cameras have hard limits
• Settings cannot invent detail
• Upgrade the key position first
• Entrances deserve the best camera
• One upgrade often suffices