Quad vs Multiplex

[rgbyhkr 0]

Ok, so I've setup various aspects of my home CCTV system already (cameras, modulator, etc). Everything is working just fine with 4 cameras modulated over my RG-6 network. Now I'm looking into quads and sequencers. In my application, I'm looking to out 2-4 cameras on a sequencing AND quad view. We use the cameras primarily as baby monitors so my wife wants flexibility.

 

My modulator is of the 4-channel variety. We use 2 of the channels for the 2 primary full-screen feeds and the other 2 for sequence and quad of all 4 cameras. So, I'm trying to find a solution that best fits our needs.

 

Of course, there's an array of choices out there. One model I have been checking out, although expensive, is Pro Video's (from Speco Technologies) RQS-20B. This unit offers me the ability to output a quad view and sequence view at the same time on different outputs. Additionally, it offers pass through connections for all sources. So, I wouldn't need to also get a splitter/distribution amp for the 2 primary feeds.

 

The question I have is in regards to how this type of unit compares to a similar unit that they describe as a "multiplexer" (specifically RMX-4CD). Now, I'm wondering if I truly understand the multiplexer term. I've seen it used in sat distribution equipment and I think it means a device that doesn't simply split a feed but rather "replicates" it to allow for all channels of that feed (in the sat distribution case) to be accessed independently by all outputs. Am I on the right track? And how would this apply in the CCTV field?

 

I know the RMX-4CD is even more expensive and may be way more than I need. I'm just trying to understand how they are different for general understanding of the options out there, if nothing else. Who knows, some of the additional features may be of use in the future and could warrant the additional expense.

 

For reference, here are the product pages for both units:

 

RQS-20B:

http://www.specotech.com/cart/products/productDetails.asp?prodID=486

 

RMX-4CD:

http://www.specotech.com/cart/products/productDetails.asp?prodID=679

 

Thanks in advance for any and all help.

[rory 0]

Ive used Quads way back when, and I have used Muxes and even the Provideo 9 channel Mux.

 

There are major differences, first the quality is much better with a multiplexer, it also sequences smoother. Recording is ofcourse the main advantage though, as a mux records each image seperately, while a quad only records what you see on the screen - when used with a DVR or VCR.

 

Personally, for the Extra $100, I would get the multiplexer, it will have more menu options as well as be slightly better quality. Ofcourse for that price, you may just want to jump up to the 9 channel one time, incase you ever want to add more cameras.

 

You may also want to look into a Budget 4 channel Multiplexer DVR, they range around $500 retail., and come with LAN for remote video.

 

Rory

[rgbyhkr 0]

Rory,

 

I apologize for the ignorance, but could you elaborate on "Recording is ofcourse the main advantage though, as a mux records each image seperately, while a quad only records what you see on the screen..."? I'm not quite sure I understand this. I thought that with the separate outputs of the quad, you could have one output showing a quad display with the other sequencing? Am I wrong on this?

 

Also, given your experience with the Pro Video units (and since they don't have a pdf manual that I can download and see for myself), does the 9 channel model allow you do just a quad split on-screen for 4 cams? I ask this because for the time being, I wouldn't want to sacrifice on-screen image size by having only 4 active squares on a 9 camera split-screen view.

 

Thanks in advance for all your help and I sincerely appreciate your willingness to offer your expertise to a novice like myself.

[rgbyhkr 0]

By the way, I'm not at the recording point yet. When I do get there, however, I will probably go the DVR card route. I'm a computer geek so while the CCTV world is new to me, building and upgrading PCs is "old hat". I like the flexibility those systems offer but still want to maintain a non-pc pathway for the modulated feeds because my wife is definitely not a computer expert. Otherwise, I'd probably roll the quad/sequence need into the dedicated PC I'll put together later for recording.

[rory 0]

Depends on the quad, most I have used, will only allow, either or, in other words, you can only view either Quad view, or Sequencing view, not both at the same time. This one looks like it may do dual monitors, and has loop throughs so it is a better quad.

 

Though, what I was meaning was, if you wanted to record, a Multiplexer will record each invidual camera in full screen, so you can play back any camera in full screen 740x480 or whatever the highest resolution is of the Mux and DVR/VCR. Whereas with a quad, you can only record what is on the screen at the time, such as quad view, which means each image is actually 740x480, divided by 4, which is much lesser quality.

 

A multiplexer is basically a super fast switcher, It sends each camera to the DVR in the multiplexed signal. The speed it sends it to the DVR depends on the speed you set the Mux or DVR to, they must correspond. So you get much better quality images on playback. A quad is not suggested for recording.

 

As for the Provideo Mux, yes you can view 4 channel (quad view) or 9 channel. Either way it will still record each image regardless of what view you have it in on the screen.

 

I actually use the Privideo Mux, along with a Kalatel Mux, with 8 Hidden cams, and 8 IR cams, all modulated to the Cable TV channels. Plus they have a single channel Kalatel DVR for recording, and remote video.

 

Rory

[rgbyhkr 0]

Rory,

 

Thans again. Any chance you have a shot of the rear terminals on the Pro Video?

 

By the way, I think I now understand the difference between the 2. I had to read your posts a few times and also check out the glossary page of another CCTV website, but I think it's clear now. In more simple terms, the multiplex allows you to take multiple camera feeds and record them all to a single VCR. Unlike a quad where the only view you get on playback is the tiled or sequnced one, the multiplex allows for playback of the tiled view and full-screen view of each feed with the latter at full-screen quality. I think that's right.

[rgbyhkr 0]

Ok, I think I found the manual for the 4-channel Multiplex. For some reason, they have it linked to the 16-channel multiplex page (none of the other multis had a linked manual).

 

Here's the link for anyone interested:

 

http://www.specotech.com/cart/products/downloads/default.asp?durl=%2Fcart%2Fproducts%2Fdownloads%2Fappcharts%2FHS%2Drmx%2D4cd%5FUser%5FManua%23BC4A5%2Epdf

 

This should answer the rest of my questions. Thanks again Rory.

[rgbyhkr 0]

Ok, I've seen the manual and it leaves me with only one thing that isn't clear. I see that I can change the output type over the monitor output, but is the output over the VCR OUT unchangeable? My thinking here is that I would have one output (say the monitor) doing sequential while the other (VCR OUT in this case) showing a quad view. Both outouts would be for real time viewing only over the moduluated channels. Can the multiplex do this?

[rory 0]

Not this one

 

It only has 1 monitor output. The VCR out is multiplexed so you just get super fast switching video .. The higher end muxes like the Kalatel have that and many more features ..but more $$. The Kalatel 4 channel is around the same price as the Provideo 9 channel. Normally you will also get an analog output for sequencing.

 

It does have S-SVHs though, and PIP ..

And if you want to delve into some coding like VB or C++ they give you the ASCII commands .. make your own Pocket PC controller software or something .. )

 

Rory

[rgbyhkr 0]

Ok, now everything becomes crystal clear. I thought that's what the VCR OUT would be in order to get the advantage that the multiplex offers. The Kalatel ones are pretty cool but as you say, they are certainly much more expensive. Also, it looks like you don't get into the dual moniro output models until you get into the middle to higher end models (all the 4-channel models I saw on their site only have single monitor outputs).

 

No big deal there. The Pro Video quad looks like it will do what I want and since I won't be recording from it, the multiplexer recording functionality would go to waste anyways. I can certainly sink the extra $$ into a kick butt PC DVR when the time comes.

[rory 0]

Have you looked at their 9 channel Multi viewer? I havet used it but remembering it being around the same cost as the 4 channel mux..

 

A quad is probably all you really do need for that app, when you get into recording, then you can invest...

 

I dont have any shots of the back of it sorry, didnt have the camera when I was installing it , it was an after thought ..

 

Rory

[rgbyhkr 0]

I just took a look at the MV-9. It doesn't have the looped outputs, but it does seem to have everythig else plus offer expandability should I go beyond 4 cams. One thing I have to remind myself of is the framerate issue. Meaning that the max framerate is set and as you split the view amongst various cameras, the framerate displayed for each cam view is a fraction of that max rate (1/4 for a quad view, 1/9 for a 9 channel view, etc). I guess that's true of all quads. Of course, having the ability to change the channel and switch to full screen (and real time fps) on one of the 2 primary cams covers that.

[rory 0]

yeah actually that is one thing I forgot to mention. The Provideo 9 channel is not real time display in 9 channel view, but the GE Kalatel is real time display up to 9 channel display. Though the display speed does not affect the recording speed on multiplexers as that is seperate. The quad though, it does. Quad would be real time either way, just smaller image in quad record, so less quality.

 

You may want to get something now though, that can come in useful when you get the PC system, as most PC systems dont do multi view output, just sequencing, I havent tried it with the ones I have here yet though, havent had the need yet.

 

Rory

[rgbyhkr 0]

Rory,

 

Just to let you know, I got the RQS-20B and it works like a charm. It does exactly what I wanted and the quality is perfect. One output is dedicated to the quad view while the other is switchable between quad, sequence or single camera full screen view.

 

I actually went a step further and came up with my own solution for audio. Nothing too creative, but my wife loves it. Since the 2 primary cams in the babies' rooms also have mics, I had to find a way to get the audio feeds from those mics to work on the quad/sequenced channels. So, I used a distribution amp to split the 2 mic feeds and send one feed to the dedicated channel, one to the quad and the third to the sequenced channel. On the dedicated channels it's just a mono feed from the corresponding mic, but the quad and sequenced channels contain a mix of the 2. It's a simple left channel taking the feed from one mic and the right channel taking a feed from the other. This way, if both kids are asleep in their own rooms, she can tune into either multi-cam channel and still hear continuous audio from both of the rooms. Nothing spctacular, but it is just what we wanted.