Digital vs. Analog Security Cameras – For Dummies

How’s it going my curious readers. As you probably know, 10 years ago, almost all security cameras systems were analog. We have come a long way since then and the industry standard today are high-resolution MP (megapixel) cameras, which provide superior video recordings, while taking up noticeably less HDD due to complex compression algorithms.
But we also see some people using older analog cameras today. Why is that so? Aren’t the analog’s passe and not as good as megapixel cameras? We’ll question that in the following post.

Analog security cameras

Nobody knows exactly when surveillance cameras became available to working class people. Throughout the 60s, 70s and beyond, they have been used on government institutions, magnate’s lavish estates and by NASA.
When the 90’s were in full effect, there haven’t been that many systems installed, but it was getting momentum. As we stepped in a new millennia, the security cameras system market exploded. Everybody wanted their system. People wanted to protect their estate, kid, wife, dogs, they wanted to supervise their employees and have a look at their beach house after a busy day.
Naturally, as analog cameras were the industry standard at that time, everybody went analog. There was a decent selection of high quality cameras (Bosch, e.g.), but there were also some lousy brands which don’t deserve to be mentioned here.

Technical specification

I’ve been looking around resources on the Internet, and I am very disappointed. Almost as if those article authors don’t want you to understand the essential difference between these two systems. We’ll, I’m here to correct that 🙂

Analog means that the signal is continuous. So, it has a value at any given point in time. This can be bad, because, when transferred to long distances signal weakens and you get a fuzzy video.

It was much harder to store this kind of data, than the digital signal, which is all 0’s and 1’s (yes power – no power). This reflected in the amount of hard disk storage a video occupied. We’re talking about video quality/storage take up ratio here, not the crude numbers.

At 2003. DVR‘s (Digital Video Recorder) hit the market. They are still used today for compressing the analog camera signal, since analog cameras don’t come with a compression processor built-in.

When they appeared, the compression format was MJPEG, which consumed way too much disk space. Due to that, it was replaced by MPEG-4 and MPEG-2 (even though the former is more efficient, the later was actually used in cctv systems; beats me why).

There is a major effort to make analog cameras work over coaxial infrastructure, thus evolving HD technology.

There are 5 technologies now for coaxial systems:

  • Analog (analog signal)
  • SDI (digital over coaxial; Sony standard)
  • TVI (the Chinese version)
  • AHD (also digital over coaxial)
  • CVI (digital as well)

The difference is that compression for these are still done at the DVR with 1 and 0 over the line (even though cameras output digital signal, the compression has to be done at DVR. Cameras don’t have a built-in compression mechanism).

I’ll say it straight away: I love analog cameras. They produce a beautiful, vivid stream, and have an old times charm to them. But, being honest with myself and you guys I gotta say: analog is history. Sorry. It’s just too big of a difference. Newer megapixel security cameras are the thing for face recognition. They produce a sharp video on which you can distinct even the most minute details. More on that in their respective section.

Don’t despair. There is hope for you analog-loving guys. Or maybe you invested too much hard earned money in your system and it still works fine, but not super fine. If you want it super fine, than you will have to open up for a maintenance, where the camera guy will tune the cameras to their full potential, maybe replace the connectors and similar. Then it can go on for a few more years, but, eventually…

Digital security cameras are the future

I kid you not. My personal experience showed me that almost half of the people who relied on analog systems have made the decision to switch over to a new megapixel system. Why? Mostly out of convenience. And quality.
Digital cameras are smaller and more practical (we’re talking about IP or network cameras here). If you make a smart decision and invest a few extra bucks in a high quality brand, I can claim that they are more reliable as well.
The super cool thing about a digital camera is this: they either work perfectly, or not at all. There is not midfield with these babies. The receiver either gets the 1’s and 0’s from the transmitter or not.
Due to this, wireless digital camera systems are gaining momentum. Due to high speeds of 802.11x standard Wi-Fi, it’s possible to send video streams through air. The digital transmission does not get interference from other analog wireless devices (cell phones, fluorescent lighting), and the 802.11x communication standard used has encryption built in. Consequently, there is no problem with unauthorized access to the video.

Digital security cameras come in different flavors. I’ve included a table just for you guys, so you can get a picture of how much HDD storage an individual configuration eats up (using MPEG-4 encoding):


Ok, I showed you the MPEG-4 values. But H.264 is the bomb. For you non-tech people, it’s the industry standard at the moment and it gives around 30% more recording time then the former. Cool huh?

To sum it up

There you have it peeps. I don’t want to be suggestive (actually I do), but if you ask me I’d always advise you to go digital/megapixel. You’ll spare yourself lots of agitation, worrying about inevitable change to digital in near future and being all “Whaaat?” when it turns out you can’t see people’s faces on the camera after all 🙂

If you have any specific questions, feel free to ask in the comments. I’ll answer as soon as I can.

Until next writing,
Jovan, your video surveillance guy.

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