The New Alphabet
High definition analog technology competes with IP cameras
- By Gary Perlin
- May 01, 2015
Mastering the alphabet used to be
as simple as learning your ABCs.
Not anymore. A whole new alphabet
has been created for the world
of analog video. Don’t try to sing this one to the
“Alphabet song” we all grew up with. It doesn’t
work. Trust me. I just spent 15 minutes trying.
The new alphabet goes CVI TVI AHD SDI
SDIv2. Each group represents a high definition analog
technology that was created to compete against
megapixel IP cameras. This article will not be comparing
Analog to IP or addressing the virtues of one
over the other, but will explain why high definition
analog exists and what the future may hold.
Let’s start by going way back in history to the
year 2012, which is ancient history in the world
of technology. Analog cameras were hard pressed
to put out an honest 700 lines of resolution while
IP cameras were easily displaying pictures of 1
and 2 megapixels (720P and 1080P respectively)
and up to 5 megapixels in some cases. On the
down side, IP cameras were expensive and difficult
This must have seemed like the perfect business
opportunity for a group of companies to create
megapixel low cost analog solutions to go up
against IP. Sadly, it arrived just in time to compete
with the new generation of low cost plug-and-play
IP equipment. I guess timing really is everything.
Let’s say you’re ready to start that new high
resolution project but aren’t sure what to use.
Both IP and analog can give your customers
a terrific solution, depending on their needs. If
for whatever reason you’ve decided to go the HD
analog route, the two most popular technologies
in analog HD today are CVI and TVI. CVI seems
to be bigger in the DIY market whereas TVI is
found in more commercial products. Both give
excellent picture quality in their 720P and 1080P
versions. The specifications of both continue to
evolve, but you should expect extended transmission
distances on coaxial cable and remote
control of key camera functions on most. Another
option, AHD, is currently only available in
720P. In my mind, this puts it at a disadvantage.
Rumors abound about AHD being available in
1080P, but I have not seen a legitimate working
sample yet. Perhaps by mid-year? Right now,
AHD is not widely available and has a more restrictive
feature set than TVI and CVI.
That leaves SDI and the newer SDIv2. SDI
has very few supporters right now and many former
SDI supporters are moving to the TVI and
CVI bandwagons. You will most likely find SDI
products built into other products such as public
A few caveats: For your convenience, none
of the above technologies work with each other.
Each technology requires its own DVR. TVI requires
a TVI DVR. CVI requires a CVI DVR,
etc. Most of these new HD DVRs will accept signals
from your older existing 960H cameras, but
from what I have seen, the results are not great.
I suggest that you should go all HD or stay with
your 960H for now. There are promises from
various manufacturers that we will soon be seeing
multi-format DVRs that will accept both CVI
and TVI. No dates have been given yet.
The pictures from these new HD products are
fantastic. Coupled with a cost that is lower than
today’s 960H products, HD analog has the ability
to change our thinking about analog for years to
come. It’s a technology that is here to stay.
This article originally appeared in the May 2015 issue of Security Today.