diff between quad multiplexers, switchers.

[jarifbasha 0]

am workin as a engineer in UAE, am totally new to this CCTV, if somebody could help me out in this topic, actually i want to know the diff between quad multiplexers, switchers.

[Metal Shaper Man 0]

A multiplexer can have a verity of features. But, as I understand them in their simplest form, a quad multiplexer will display and/or allows one to record all four cameras at one time in quad view. One can also display each of the four cameras independently, one at a time, full screen.

 

A switcher only displays and/or allows one to record one camera at a time, full screen.

[kensplace 0]

A quad is for combining 4 cameras into one screen, ie 4 small images (camera 1,2,3,4) making up the whole picture. You can see al the cameras, but they are recorded all at once, so each one is only one quarter of its real size. If you record the output from a quad onto a VCR or DVR, and play it back, it would play as it was originally recorded, and be viewable, but each camera would be only 1/4 of the screen.

 

A switcher is a simple switch, you manually switch to a camera when you choose to, some can be set to automatically switch through the cameras every so often. When one is being viewed/recorded, the others are not...

If you record the output of a quad onto a VCR or DVR and then play it back, it would show you the cameras that you had selected at that time, or that it had switched to automatically.

 

A Multiplexer records however many cameras it handles (ie a 4 channel multiplexer can handle up to 4 cameras) each camera is recorded FULL screen, but they are recorded timelapse style. For example, it will record camera one, for one frame, then record camera two for the next frame, then record camera 3 for the next, and finally camera 4. Then it starts again with camera 1.

 

As it records full frame, you get the full detail, but at a reduced frame rate, the more cameras the multiplexer is handling the more reduced the frame rate. Intelligent, decent multiplexers can have motion sensing, or alarm inputs, so that when a event occurs on one of the cameras it is given priority over the others, so gets more frames recorded during the event.

 

If you record the output of a multiplexer onto a vcr or dvr and play it back, directly (WITHOUT using the multiplexer again to decode it) it would show up as a fast moving sequence of different camera shots, pretty impossible to tell what is going on! To play back the multiplexer recordings, they need to be played back through the multiplexer in play mode, where it seperates the camera shots, and only displays the ones you want.

Simplex multiplexers can only not play back whilst still recording, nor record while playing.

Duplex multiplexers can playback whilst still recording, and record whilst playing.

Be aware that you usually need a compatible DVR or VCR to work with a multiplexer (not always, but often) as they rely either on a electronic signal or a signal in the video signal to sycn frame switches.

 

A Quad multiplexer, errr, that could be either a quad, or a 4 channel multiplexer, you would need to check with the supplier, as they are usually one or the other (BUT multiplexers can often display quad views whilst still recording the cameras in multiplex full screen)

 

Multiplexers can also vary in the speed at which they can record, the extra features, and even in how much of the frame they record (some cut parts off)

 

Hope that helps.

[robert 0]

so which one would be able to see in quad view 4 cams while all 4 are still being recorded at full screen - Quad multiplexer ?

[mr.surveillance 0]

A Multiplexer will record full screen, giving you the choice of live view or playing all or any one screen (some have pip)...

A Quad will only record all 4 or or one to the tape or DVR. (if you record all4 you will only get one screen with four pictures 1/4 of the screen) and crummy resolution...

 

 

A multiplexer rapidly switches the cameras encodes and decodes them on playback so you can see all on one screen or chose different cameras full screen when playing back.

 

One way or another, you always pay for what you get.