wattwire

silicuda, Man, your situation really sucks. I can't imagine the stress you must be going through. I have a high resolution (700tvl) analog license plate camera that I've been meaning to test (for resale purposes) for quite awhile and this seems like the perfect excuse to get going on this project. If you conduct the following information gathering exercise, I'll do my best to simulate the conditions at my local and post test images: 1. Determine the best location at your place to mount the LPR (lic plate recognition) camera. This spot will be the best for seeing cars head on or from the rear--with an angle that is most direct. Of course, the closer you can get to the road, the better....but should also be able to mount the camera about 3m high (to make it out of reach of the general public). 2. We will call the above spot "Pt A". From Pt A, measure the distance to the middle of the road where a captured license plate might travel. Note, this isn't where the camera will be focused; but rather the shortest distance at a perpendicular angle (90 deg) from the camera to the middle of the road. We'll call this "Pt B". I'm assuming that there's a road in front of your place that runs in a straight line. 3. Now take a second measurement, the distance from Pt B to where the camera will be focused for capturing plates. My camera has a 6-60mm varifocal lens, so the overall length from this point to the camera shouldn't be more than 35m. We'll call this "Pt C". 4. Take / post the following digital pictures: a) From the camera location (Pt A) to Pt C during the day, preferably of a car passing by. b) Same as above, but at night c) Daytime: from A to B, B to A, C to A, just to see if there are any other factors such as branches, mounted lights, or anything else that might interfere with capture. I also have a Dahua 1080p 8-22mm with IP camera with 36IRs I can test. I should also explain that the above Points A,B, and C form a right triangle which will allow me to calculate the camera angle (to the straight line of the moving vehicle) and the distance from the camera to the capture area. I mentioned 35m above as the maximum distance because with a 60mm lens fully zoomed, the horizontal view area is about 3M wide. This can be figured out with a lens calculator, like the one on Pelco.com. Also, this might be a silly question, but do you currently have a DVR installed? If not, you have to think about how all this is going to be recorded an retrieved later. -d

A search on Newegg of "powerline networking" shows these devices have come way down in price. You can now get a PAIR (Tenda P200) of adapters for $30.00 w/ free shipping. I've used other brands with great success. They're fast and easy to install.

Nice shots Shockwave! What Dahua model are those from?

Even with a good LPR camera, it's going to have to be aligned almost directly in line with vehicle travel direction. This is going to be hard to achieve on a public street unless your property is at the end of a "T" intersection.

I sell and install Dahua IP cameras and am happy to share my actual power consumption measurements for a few models (day / night): HDB3200 (your 1080p mini dome w/ no IR): 3.2 / 2.9w HDW2100 (720p eyeball dome with IR): 2.1 / 3.1w HFW2100 (720p small cyclinder with IR): 2.4 / 4.8w HDBW3202 (large VPD with IR): 5.0 / 6.1w Notes: o These are short runs for testing of < 30'. For long runs there surely will be significant voltage drop, so I did a test and connected one of the cameras up to a 200' cable but saw no power output drop from the switch (it was previously on a 10' cable). So the camera was able to handle a voltage drop okay. o I used a managed POE switch to take these measurements which made it pretty easy. Now back to your original question--if you're only planning on having 5 cameras, the most economical solution may be to buy a switch with 4 POE ports and then use an individual POE injector for the 5th camera. The Trendnet TPE-S44 and ZyXEL ES1100-8P are a couple of models to look at for good price / performance. The Zyxel has a higher rated power budget but you probably don't need that. -d

Yes, different metrics. This is the key to my confusion. The arithmetic of reducing the horizontal resolution to accommodate a 4:3 aspect ratio is pretty straight forward. But isn't the CIF standard for NTSC already set at a 4:3 ratio? (352/264). So the theoretical maximum number of horizontal pixels that would benefit the quality of a digitized image is 440? (330 * 4 / 3). The only reason I referred to CIF in the first place was because it was a known number of pixels. Hmmm, maybe we need to investigate what pixel is and what TVL is. Actually, I'm more confused than ever now. This is a good thing though, because I'm probably on the verge of learning something. Amir, thanks for having the patience in explaining this. Understanding how TVLs relate to pixel dimensions of digital images recorded by a DVR has got to be one of the most important concepts there is in CCTV. It plays a hand in how we select cameras, transmission methods, DVRs, and display devices, and more. So at the risk sounding ignorant, I'm going to take another shot at trying to get at the bottom of what a DVR can record (with no compression) from a baseband signal coming from a camera over coaxial cable. I think my biggest stumbling block is understanding what a TVL is. Here's what I've gathered from what I've read and been told: The maximum number of vertical lines going across the screen whereby each can be individual resolved. Said another way, if you could make a uniform bar code and place it in front of a camera, how many vertical lines there would be before the black ones merged together. I guess this also relates to the modulated electrical pulses in the signal (but we don't need to get this deep). I feel much more confident about what a pixel is as it relates to a digital image. It is the smallest unique picture element that can be modified. What I really want to know is: What is the maximum number of unique (not merged) pixels of information than can be recorded/digitized on a DVR coming from the baseband signal of an analog camera? If we took the uniform barcode example, how many white spaces and black bars could we individually distinguish before they started to merge together in the digitized image? Thanks!

Actually, that assumption is not correct. NTSC does exceed the resolution of CIF. As I said: "And in the case of a DVR doing a poor job of compressing the content, then the extra resolution NTSC has over CIF is probably lost," it is the combination of poor video compression and NTSC that might eliminate the extra resolution benefits of 4CIF. Bear with me a bit as I suffer from mild retardation at times. I'm probably missing something here about the basics. For a moment, let's put aside discussion about compression. My understanding is that TVL represents resolution going horizontally across the video scan line. I understand that the scan lines are interlaced and alternately refreshed. The resolution of CIF for NTSC is 352x240. So my original question was focusing on the fact that 352 > 330. What am I missing here?

Amir, that was a nicely written tutorial in the drama filled thread about camera resolution. I feel very lucky to have the attention of an experienced video engineer. More people need to point out that we're working with a signal standard here (NTSC) that doesn't dynamically change to accommodate higher resolution cameras and recording equipment. Having said this, I'm still struggling a bit trying to understand the maximum resolution that video transmitted over coaxial cable can be recorded at. In particular, I have to ask, "How is it that recordings at 4CIF look better than 1CIF given the fact that 1CIF exceeds the 330tvl frequency limitation of NTSC?" Is it possible that the baseband signal from cameras is exceeding the NTSC standard of 4.2 Mhz and approaching the 6.75Mhz "studio frequency" you mention in the other thread?

CIF images are going to be soft no matter how little compression artifacts there are. Sure, if you are bandwidth starved, then an H.264 at lower resolution may be superior but if motion is small, even that won't be the case. How do you get near DVD when you have one quarter the resolution? I'm working with a Blackfin DSP based H.264 DVR now and I can vouch for the concept that the 1CIF looks very good and exceeds the quality of "D1" recordings from other DVRs. Unfortunately, for my DVR, the D1 quality only increases marginally--even when testing with a very high quality 540tvl camera. There's definitely a difference between the two, but not nearly what you'd expect for having 4X the frame size. My theory on why 1CIF can look nearly as good as D1 is based on the belief that the image constructed in the DVR's frame buffer doesn't come anywhere near representing the resolution we think it does. As a matter of fact, I bet the real resolution is closer to 1 CIF than it is to 4 CIF. The frame buffer is 4 CIF, but the image has been expanded to fit. An analogy can be made from working with an image editing program like Photoshop. You can take a not so sharp looking picture and make it look good by shrinking it some (1CIF)...and if you expand the shrunk image back up, it doesn't look that much different from the original. However, there's very little you can do to improve the original picture because the image information just isn't there, even if you try to expand/increase the resolution (4CIF).

Hello, Wow...Thanks again wattwire. Ok.. Actually i would like to set up CCTV system for my house ( inside the house and house compound ). The distance between cameras and the recording equipments is about 250 meter , 450meters far ,maybe some of them further....And can you roughly explain what is Cat5e with passive baluns and Cat5e with active baluns ? Thank You In the simplest terms, video baluns are small devices that allow the use of UTP cable to transmit baseband video which is the output from security cameras. Baluns work in pairs--one is connected at each end of the cable and usually has a bnc connector to connect to the camera and DVR/monitor. The terms passive and active could be substituted for the "non-amplified and amplified". I do not necessarily endorse this company, but Active-Vision has a selection of baluns for sale and also provides more information: http://www.active-vision.com/Video_Balum_s/35.htm?gclid=COe_oqzJ6ZYCFQv7agodkheIPg Here is an article on what UTP is: http://en.wikipedia.org/wiki/Unshielded_twisted_pair#Unshielded_twisted_pair_.28UTP.29 There is lots and lots of discussion about using coax vs. UTP. In general, the advantage of UTP is that the cable itself is cheaper and smaller in diameter making it easier to work with. Note, the savings in the cable itself may be offset by the cost of the baluns! Coax is heavier and tougher. My opinion that it is more reliable based on the fact that there are fewer connections and the strength/durability of the cable. Fewer connections for coax because a balun requires two at each end--the wires going into the balun and the balun connecting to the video device. Having said all that, I use both UTP and coax depending on the circumstances. -dw ps, you never mentioned how far your run lengths are for supplying power to the cameras. Don't overlook the requirement to power the cameras. Improperly powered cameras is one of the main sources of CCTV trouble.

Survtech makes a good point and I'm beginning to get the picture. The associate has a large stock of non-Pelco conforming PTZs and wants to use them with cheaper DVRs that only recognize Pelco D (or vice-versa?). This is a little off subject, but I have to share the fact I've recently installed a Wonwoo WSJ-300 PTZ and was delighted to discover that it had a multi-protocol "auto sense" setting. All that I needed to do was set the baud rate/parity and it just works given that it receives one of a long list of protocols it recognizes. This could solve the problem of having a DVR and PTZ joystick controller that don't share a common protocol. For instance, I have an older Pelco KBD300a controller that only speaks Pelco P. The Wonwoo PTZ could work with this controller and a Pelco D (yes, "D" also works at 4800 baud) only DVR at the same time. Slick. -dw

I think you got some bad info about the range of Cat5e (or Cat6) video transmission using passive baluns. Or perhaps you left off some 0s The range is greater than that of coax. If you use active baluns, the range jumps well over 1km. Yes there amplifiers for coax but GENERALLY (others can pipe in) the strategy for long runs in order of distance is: 1) Coax 2) Cat5e with passive baluns, 3) Cat5e with active baluns or fiber. 4) Long range microwave (wireless) The best thing is for getting help in this forum is to state your scenario: 0) What is the general environment (new construction, commercial building, private property, in the jungle, on a farm, etc.) Also the climate can be a factor if the cable to be run outdoors. 1) How long is the distance between cameras & recording equipment? 2) What is the distance between cameras and power source? good luck, -dw

http://www.ikegami.com/cb/products/pdf/tech/simplesystem.pdf Make sure your coax has a solid copper center conductor and copper braided shielding. There should be no aluminum nor steel used by the cable. If you're using siamese cable, the ikegami document doesn't apply--the run lengths are much shorter for the power conductors due to voltage drop. I can't make heads or tails out of this question, "Is there any hardware like switch for coaxial ?" -dw

Oh man, that really sucks. Those Bastards! Even though it makes for good video, I feel really bad for you. Speaking from experience, being the victim of a crime like this is no fun. If you were nearby, I'd buy you a drink or two. Be on the lookout for one or more of these chumps in the future. There's some truth in the saying, "The criminal always returns to the scene of the crime." In any event, the odds are that one or more of these guys lives close to you. BTW, I assume you gave a clip or two to the authorities. Tell us the details--what form was the video in (USB Thumb drive? CD? .AVI? Tape?), what comments if any did the police make about the video? Cheers, -dw

Whoops, had to edit my message to get the polarity of the power correct. That's what I get for making late night posts while tired. The common ground is true, I was just thinking in terms of the output connections normally seen with a dome camera. I was assuming that the camera didn't have a microphone. If it does, then Soundy is right on with the wire assignment.

My guess is similar. red= +12vdc black= -12vdc yellow= +video white = -video. I'm more certain that red/black is your 12vdc power. Yellow is definitely part of the video signal. I don't know if I've ever seen power and video share the same ground, but I could be wrong.

"Converts any hardwired PTZ to PELCO D..."??? Quite a claim. Sounds like a prank product to me, but I found a couple of places that claim to sell this contraption. Here's one with a listed price: http://www.peekaboo4u.com/Eclipse%20CCTV%20new/webpages/CCTV_Controllers2.html Still, it looks bogus to me. -dw

Sweet system! Looks like a lot of hard work that paid off. Are you using motion detection recording? How many days of archive video are you shooting for? -dw

I had a look on ebay and all i could find are DVR with an RS485 output but no input, the only input is through the internet. Im guessing you would need an input from the Keyboard controller so the DVR would change to the channel you choose on the keyboard controller. Have you any idea where i could find a DVR like what your talking about and for ok money? I like your idea as it would save alot of hassle. This is a good idea. Virtually all DVR have a connectors for RS-485 PTZ control. The wiring is just 2 conductors (1 twisted pair of 24awg networking wire). This will not be an isssue with your DVR. Man, if you're buying 6 PTZs, you should invest in a decent DVR. i dont need the dvr for recording, all i need it for is to wire all the cameras into and i am hoping to wire the keyboard controller into it also so that when i choose to look at lets say camera 002 then the dvr will change the channel displayed to the camera 002 by the input of the keyboard controller. Is this possible? i seen rs485 output on dvr's but could not see an input One morning you find a lost and confused two-headed calf wondering in the pasture. All the cows dis-own it and don't even acknowledge that it is of the same species. Without a DVR recording how are you going to find the real mother?!?!?!?! BTW, you never answered the question about powering the cameras. This makes a difference in the wiring / cable choice. the cameras will all have their independent power supply as the shed is already wired for this. the PTZs are to be placed in a shed where they will monitor a series of individual calving pens. i only need the DVR to be able to switch to which ever camera i am controling as i will be monitoring this live. In my last response I made the assumption that there might be users in the 3 rooms simultaneously controlling the cameras. If this is not the case and you had either a desktop computer or laptop, the solution could be simplified by having just one DVR in the closest room. You could then use fairly inexpensive video splitter/amplifier to repeat the video to the other two rooms. A remote connection via a laptop/desktop in the other two rooms could be used to control the DVR for selecting cameras. Here are some other thoughts: I you didn't have computers in the other room you could use IR repeaters instead that you'd point the hand held remote for the DVR at. Also, if you used a professional video monitor in the second room you wouldn't need a splitter because the monitor would have a "video out" connection for the 3rd room where a standard TV could be used. I'm sure there are about a 100 more possibilities, but this is what comes to mind of the top of my head. -dw

I had a look on ebay and all i could find are DVR with an RS485 output but no input, the only input is through the internet. Im guessing you would need an input from the Keyboard controller so the DVR would change to the channel you choose on the keyboard controller. Have you any idea where i could find a DVR like what your talking about and for ok money? I like your idea as it would save alot of hassle. This is a good idea. Virtually all DVR have a connectors for RS-485 PTZ control. The wiring is just 2 conductors (1 twisted pair of 24awg networking wire). This will not be an isssue with your DVR. Man, if you're buying 6 PTZs, you should invest in a decent DVR. i dont need the dvr for recording, all i need it for is to wire all the cameras into and i am hoping to wire the keyboard controller into it also so that when i choose to look at lets say camera 002 then the dvr will change the channel displayed to the camera 002 by the input of the keyboard controller. Is this possible? i seen rs485 output on dvr's but could not see an input One morning you find a lost and confused two-headed calf wondering in the pasture. All the cows dis-own it and don't even acknowledge that it is of the same species. Without a DVR recording how are you going to find the real mother?!?!?!?! BTW, you never answered the question about powering the cameras. This makes a difference in the wiring / cable choice. the cameras will all have their independent power supply as the shed is already wired for this. the PTZs are to be placed in a shed where they will monitor a series of individual calving pens. i only need the DVR to be able to switch to which ever camera i am controling as i will be monitoring this live. Ok, it seems to me that you could place an inexpensive 8ch DVR in each room and use it two select various cameras/views by hitting buttons on the unit as you suggested. Make sure the DVR of choice has looped outputs to connect the output of the first DVR to the input of the 2nd and so on. Most DVRs also allow you to control a PTZ via its IR remote, but a 3-axis (twisting) controller is much more enjoyable to use. Cat5e with passive baluns should work fine for the distances you mentioned. The PTZ control signal would be wired using Cat5e. The control cable would be connected in a series starting with the PTZ controller farthest away at one end, then the next controller and on down the line to the farthest PTZ. If you have no interest in controlling the cameras over the network, then don't even bother connecting the RS-485 wires to the DVR. Otherwise, connect the DVRs like they were additional controllers (ie, in the series). Note, that some PTZ controllers may interfere with the PTZ control of a DVR (that's my experience, yours may differ). Obviously there is the potential that 2 users could be fighting over control for one camera (especially if some exciting is going on like the birth of a two-headed calf ). This is sort of a complicated project--make sure you draw yourself a nice picture before getting started.

Hey Scorp, I know you're an AVTech Grandmaster Guru...could you do a little test for me? Download 1Mb of archive video from one of your 8 / 16 channel units and report the duration in seconds of the clip. Make sure it's NOT from camera #1 (I assume your record settings would be "Best"/"Frame"). It would also be interesting to know what the encoded frame rate of the converted .AVI file is...but I don't want to trouble you too much. If the clip is around 34 seconds, then I'm guessing the frame rate is 4fps. Cheers, -dw

Can anyone get more than 4fps recording performance from any of these AV Tech models: AVx 715, 717, 785, or 787...on any channel 2 or higher, with the recording parameters "Frame" and "Best"? The recording IPS should be 60 for 8ch or 120 for 16ch. Take the test: 1. Download 1MB of recorded video via client from camera #1 and any other camera. 2. Load the clips into the "Video Player" program. Note how many seconds of video you get for each clip (remember, they should be about the same file size of 1MB). 3. Convert the clips to .AVI files. Use Windows Explorer to see what the frame rate of each .AVI files is by clicking "Properties", and then the "Summary" tab. 4. Bonus points if your video clip contains moving objects, this will give you a better idea of the practical difference in frame rates. Now that the challenge has been made, let me share my experience. Recently I purchase a new AVD715 (8 ch. flavor) DVR and have been running some recording tests. Right away I noticed that channel #1 seems to do a pretty good job, similar the AV761 that I own. However, all other channels seemed really jerky when playing back video of moving subjects. After scratching my head a lot, I decided to set up two identical cameras with identical cables & power, pointing identically on the same scene. I then recorded 30 seconds of video (me pacing back and fourth) and down loaded the two clips from the DVR. I was STUNNED to see that despite how many times I repeated this test, the clip from camera #1 was about 6X the file size of camera #2. The following did not make a difference: Motion Recording or Manual Recording From the "Record" Menu...IPS Share of "Group" or "Fix" Downloading to CD, USB flash drive, or Network Note, the DVR has been upgraded to the latest firmware version by my dealer. When converted to .AVI I found that channel #1 had been encoded to 18fps while all other channels were encoded to 4fps. My suspicions are that the 16 channel models will behave the same way, but I'm not sure. There's also the fluke chance that something is wrong with my particular DVR. Of course, the probability is greater that I'm losing my mind, I've grossly overlooked a setting, or have now have "special needs" than I'm not aware of. Cheers to anyone who reads this and/or reports back testing of their own unit, -dw

I had a look on ebay and all i could find are DVR with an RS485 output but no input, the only input is through the internet. Im guessing you would need an input from the Keyboard controller so the DVR would change to the channel you choose on the keyboard controller. Have you any idea where i could find a DVR like what your talking about and for ok money? I like your idea as it would save alot of hassle. This is a good idea. Virtually all DVR have a connectors for RS-485 PTZ control. The wiring is just 2 conductors (1 twisted pair of 24awg networking wire). This will not be an isssue with your DVR. Man, if you're buying 6 PTZs, you should invest in a decent DVR. i dont need the dvr for recording, all i need it for is to wire all the cameras into and i am hoping to wire the keyboard controller into it also so that when i choose to look at lets say camera 002 then the dvr will change the channel displayed to the camera 002 by the input of the keyboard controller. Is this possible? i seen rs485 output on dvr's but could not see an input One morning you find a lost and confused two-headed calf wondering in the pasture. All the cows dis-own it and don't even acknowledge that it is of the same species. Without a DVR recording how are you going to find the real mother?!?!?!?! BTW, you never answered the question about powering the cameras. This makes a difference in the wiring / cable choice.

I had a look on ebay and all i could find are DVR with an RS485 output but no input, the only input is through the internet. Im guessing you would need an input from the Keyboard controller so the DVR would change to the channel you choose on the keyboard controller. Have you any idea where i could find a DVR like what your talking about and for ok money? I like your idea as it would save alot of hassle. This is a good idea. Virtually all DVR have a connectors for RS-485 PTZ control. The wiring is just 2 conductors (1 twisted pair of 24awg networking wire). This will not be an isssue with your DVR. Man, if you're buying 6 PTZs, you should invest in a decent DVR.

Question: What about power to the cameras? Can that be done locally or are you going to power them from near the DVR as well? I usually use a single combination cable that has power + two twisted pair for video and PTZ control. However, I have not seen a direct burial version of this cable so you'd have to use conduit. Perhaps an easier way would be to run two separate cables to the camera--direct burial power (16/2 or 18/2) + direct burial cat5e. You mentioned that the output had to be piped into 3 separate rooms. Do you need to control the cameras from three separate rooms as well? Whatever you do, don't try to split a single video out (from the DVR or camera) using a simple passive splitter or "T" connector. -dw