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Saturday, September 23 2017 @ 02:24 AM CDT

Types of Cameras

Previous: Cameras Overview - Next: IP Camera Control

As noted in the camera overview section, there are 4 main types of cameras you might choose from when you create a wildlife stream:

  • bare industrial composite video
  • pre-packaged industrial composite video
  • IP industrial
  • consumer video/web

The useful ones today are the bare composite video and consumer, with industrial IP from selected manufacturers coming in a close third, but being fairly expensive.


Bare Industrial Composite Video

The bare industrial cameras come in two different basic types:

  • Built-in lens
  • Add-on lens

The built-in lens variety are typically the less expensive, and you'll need to choose mostly based upon what lens length you need. Most such cameras are "Quarter Frame" image area and the lenses range from 2.5mm to 10mm focal length. The 2.5mm lens has a very wide field of view and is best suited to installing very close to your subject. The longer the lens, the more "telephoto" it is, so the 10mm lens will have a much narrower field of view and be best suited to mounting some distance from the subject.

These fixed-lens cameras usually also have a fixed and very small aperture, so they have great depth of field (acceptable focus distance from the camera) although as with any camera, the shorter the lens, the greater the depth of field. Some of these cameras have such good depth of field they don't have any means of focus at all - relying solely on the fact their lens is of short focal length and their aperture is tiny to give acceptable focus from a few inches in front to infinity.

One major thing to know though is that the smaller the aperture, the less light the camera can take in, so these fixed focus cameras typically are not as good in low light as others might be.

The cameras with add-on lens allow you to select the lens that will do the job, while selecting the camera that will perform (or be priced) for your critter. You'll have a choice of very low light capabilities or Infrared, and can marry this with one or more lenses you can swap out, or a zoom lens that you can use in a variety of situations.

The most typical lens mount for cameras is the "C" mount, a screw-on lens mount that screws into the body of the camera. The range of lenses you can choose from is every bit as large as that of the typical 35mm consumer cameras, from very wide-angle to extreme telephoto, zoom, powered zoom and everything in between.

The cameras that use these lenses also vary from very simple to extremely complex and expensive. Housings for all manner of applications are available, including underwater to almost any depth. 

Pre-Packaged Industrial Composite Video

Mounting a bare camera in a housing takes a bit of skill. The pre-mounted ones are much easier as most use fairly standard (and large) mounting bolts to hold them in place, or have mounts pre-built for hanging on the side of a building or on a wall/ceiling. Of course you're not likely to find a wall or ceiling near your critter, but I'm sure you can come up with something.

The most typical pre-packaged industrial cameras for wildlife viewing are those packaged for the security industry. They can be had in full weather-proof housings with heaters and fans, and in many different varieties and packages. You may find used equipment from security vendors where they are moving to the IP cameras that are becoming more prevalent these days. The older cameras will still work fine for your use, and should be a lot less expensive than purchasing new.

The output from these "composite video" cameras is usually a coaxial cable similar to what you might find hooked to your TV set's tuner. The signal on the cable is high frequency video, and degrades with distance, but should be more than adequate over several hundred feet. See the section on overcoming distances for some pointers on this. The connectors are typically "F" style, screw-on, and cable can be purchased from many different places.

The typical connector wire you find at your local stereo store should do for short runs but is not designed for outdoors. You'll want to find a supplier for weather-proof RG-6 cable to run any distance without degrading the video signal. 

You'll use a video capture device to convert the composite video (and output from a microphone if you have one) into digital video. See the section on PCs and Encoders.

Industrial IP

The industrial IP (internet protocol) cameras can be used but they take special software to make them compatible with the distribution networks and at this time those distribution networks have not made it easy – but I know they’re working on it. There is, however, one easy way to use them today and that is in a mixed IP/composite way – where you control and monitor via the IP facility but the actual video to the internet goes via a composite output to a standard encoder computer and then to the net. It may also be possible to "screen-grab" the output of these cameras using the facilities of some PC streaming video production software, but you should not count on this, especially for "unattended" systems.

Some of the cameras hide their composite video output behind a rear-panel and some don’t bring it off the board inside at all. I’ll not go into the details here of how to fix that but if you’re a bit tech savvy you may be able to identify where such a connection can be made – although damage to the camera and its warranty is on your head.

One manufacturer, Axis, makes a software “shim” that presents the video from their camera to Windows operating systems as if it were coming in via a video capture card. This facility makes working with their cameras fairly straight forward, but you must be on a LAN with the camera as it uses the Motion JPEG output which uses a lot of network bandwidth, and using this facility may not be the best idea for unattended systems.

Basics of IP cameras

The basic IP camera combines a fairly standard camera of some sort, usually similar to the bare industrial composite ones, with an “embedded” computer of some sort running an operating system that might even be similar to what you find on a PC (embedded Windows on yours and Linux on mine), or something completely different that is 100% proprietary. The CPU takes the video (and maybe audio if you plug a microphone in) and encodes it using one of a fairly short list of “codecs” (algorithms that compress the signal and turn it into bits on the internet connection) and then packages the video and audio streams into a “transport” stream that includes time stamps so the video/audio (and things like closed captioning and alternative audio, etc.) streams can be synchronized together at the receiving computer.

The problem is that there are many different codecs and several different transport stream setups, and they are not always compatible with each other, let alone the standards we use in the internet. To top it all off, most of the codecs are patented or otherwise licensed in such a fashion that in some cases it is literally illegal to send their contents to more than your camera’s licensed limit of viewers unless you do things to circumvent this. The legalities are such that I won’t make any claim that what I describe here is legal in your particular situation – that is between you and your lawyer and the manufacturer of the camera/software.

At this time I know of no IP camera that streams live using the Adobe Flash or Windows Media stream transport and a compatible video/audio codec right out of the box. All require some re-encoding or re-working of the transport stream. In some instances this will be done by a friendly distribution facility but in most cases you’ll have to do this yourself. See the Production section for some ideas on how.

What Works for IP Cameras

Without going into a whole lot of detail at this point, the “best” combination I’ve found for unattended, live, real-time extraction of video from an IP camera is H.264 video codec and AAC audio codec wrapped in a MPEG-4 transport stream. This can also be called “MPEG-4 part 10” (vs. for example, MPEG-4 part 2 which uses a different codec and is not compatible with flash)

With this combination and the help of a free version of the Wowza streaming server (free for 10 or less streams) running on Linux, we’ve streamed several different such cameras fairly successfully through the WildEarth.TV production center.

Note: For Axis IP Cameras- Specifically with Axis IP cameras there is an “Axis Capture Driver” for Windows that will allow you to use the stream from an Axis IP camera with Adobe’s Flash Media Encoder (version 2.5 at least) even though it says it is only for Windows Media Encoder.

Beyond this, the world is really at the point where what works is anybody’s guess and only combinations that have been tested and fully documented are a sure thing – a VERY short list. There are a number of open source tools that allow streams to be re-encoded and re-wrapped, but at this point they are not suitable for long-term use as they don’t elegantly recover from stream errors (and stream errors always occur it seems), so need some fairly complex watchdogs placed on them to restart them when a failure is detected. This restarting interrupts the stream for varying periods of time and so the streams cannot be truly said to be full-time.

There may be proprietary packages that do a fine job, but at this point nothing I’ve seen or tested makes their cost acceptable to the amateur. I’ll leave a more in-depth analysis of these packages for another book for the professional.

There are also any number of ways of getting around the use of proprietary software and somehow getting your video out to the world, but most of these ways involve setting up a desktop computer and running the system from the console in a fashion that is simply not very useful when you want to run a stream live for months on end at a location away from your home or office. The easiest is to use a PC that has a video card with "TV" or composite video out, and connect that output to the "real" encoder - setting the initial PC's view to what you want to send, and re-encoding it on the second PC. The details are left to the reader.

Licensing

As noted above, the codecs used by IP cameras are mostly encumbered by patents and licensing. The H.264 codec has been made “royalty free” for free internet distribution “forever” (extension from the end of 2010 announced early this year) by the patent holders (MPEG LA) See the section on Patents for more on this situation.

Consumer Video/Web Cameras

Using a cheap video camera such as those from Sony or Panasonic or any other "consumer" video camera is possible in some cases. Many of these cameras have either a USB or Firewire connector on them and will dump their video to your PC through this but... Beware that some will not let you do this directly from the video camera, only from the tape or other internal storage device, so they can't be used as real-time cameras.

Other cameras we've seen will go into "Web Cam" mode and send video real-time, but restrict the use of zoom or other settings. Be aware of this and don't just go and look for the connector, test it and ensure it works before you purchase, or be prepared to take the unit back and complain. We've noted that mostly the inexpensive units remove this real-time video transmission, even though the facility may be in more expensive versions of the same camera, and it is only the menu item that has been dropped to distinguish the less expensive unit from the more expensive one.

Web Cameras, those specifically designed for direct use on your PC via USB (mostly) or Firewire (sometimes) are typically some of the least expensive cameras you can use to watch your critters. The major problem with them is the USB/Firewire lead itself, and the fact that these signal leads have a fairly short maximum length before the units simply don't work. 

We've seen USB range extenders but have not tested one at this time. These use "twisted pair" cable which is the same as Ethernet, and most in fact come with RJ-45 (Ethernet UTP) connectors on them so you can use standard Ethernet cables. Their claim is extension to 150 feet which is about 4 times the typical maximum.

After all this, your choice of your first camera for your critter may simply come down to what you have at hand, or what you can scrounge our purchase cheaply in your area. What you choose for your second camera, because you WILL want to do this again, we're sure, will depend on how successful you are with your first one.

Tag: camera ip camera industrial camera consumer camera bare composite composite video axis 206 licensing h264 flash codec

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