Quadrox QGuard Installation Manual - Manual (Page 56)

GuardNVR Installation Manual 56
Version 4.4 Series
5.2.4 “Differential” live streaming
In order to further reduce the bandwidth requirements for live streaming, Quadrox engineers
have devised an extra algorithm that can improve the JPEG streaming for analogue cameras.
When using differential live streaming, only the parts of the image that actually change
visually are transmitted to the viewing component. At the receiver side, the parts of the image
are recombined into a full image. In terms of quality, this form of data size reduction can
hardly be noticed, but the bandwidth is reduced drastically. This allows us to stream high
quality video over a lower quality bandwidth.
If you want to remotely access the GuardNVR video server over the Internet, it is
highly recommended to use differential streaming. Another possibility is using Low
Bandwidth streaming. More info can be found in the User Manual.
This feature is not available for network cameras. Low Bandwidth streaming is
available for both analogue and network camera’s.
5.2.5 Activity detection for storage
For storage, we can apply a similar principle. Only the images that have meaningful activity in
them need to be stored. When nothing is happening, recording can be suspended. To better
distinguish meaningful activity from “background movement” (e.g. a street nearby, a moving
tree), masking can be applied to take only certain parts of the image into account.
This technique not only reduces the storage requirement, but also makes it much easier to trace
important events in the recordings afterwards, saving you both money (hardware) and time.
Using activity detection is highly recommended in almost all cases. Typically, it allows you to
increase storage time up to 400%. For cameras with little motion, e.g. in an empty hallway in
an industrial facility, it can even reduce the storage space to about 1% of the original volume!