FPS,IPS,PPS

[cliffschmidt 0]

Whats the difference between FPS, IPS, and PPS? They seem to be the same thing, but I just want to be sure:)

Edited May 5, 2009 by Guest

[scorpion 0]

There are too many variables. Some manufactures may have their own terminology that may use the same abbreviations. Buyer beware.

 

Television is an old technology, and the industry is so desperate to evolve in to new technology.

 

Back when tubes ruled the day instead of transistors it was hard to make an electronic circuit "work fast".

 

They came up with some pretty good "tricks" to overcome the limitations of the technology at the time.

 

They devised a system that would make a picture by scanning the odd number of lines, and then come back, and "fill in the picture" by scanning the even number of lines.

 

A scan is called a field. In other words it creates two fields to create one frame.

 

60 fields is the same as 30 frames.

 

The afterglow of the phosphor of CRTs, in combination with the persistence of vision results in two fields being perceived as a continuous image which allows the viewing of full horizontal detail with half the bandwidth that would be required for a full progressive scan while maintaining the necessary CRT refresh rate to prevent flicker.

 

Only CRTs can display interlaced video directly – other display technologies require some form of deinterlacing.

 

 

 

What one needs to know in regard to DVR is the selection of frames per second. If we want 30 FPS to have a movie like quality then we need this number multiplied by how many camera channels there are.

 

A 4 channel DVR should be rated at 120 FPS. 30X4=120.

A 16 channel DVR shoud be rated at 480 FPS. 30X16=480.

 

People have purchased a DVR rated at 30FPS thinking great this is movie quality! 30FPS divided by 4 channels is 7.5 FPS on each channel. In other words the playback will look more like a series of snap shots rather than watching a movie.

 

http://en.wikipedia.org/wiki/Interlace

 

http://en.wikipedia.org/wiki/Progressive_scan

 

http://en.wikipedia.org/wiki/NTSC

 

http://en.wikipedia.org/wiki/Raster_graphics

 

 

http://www.ev1.pair.com/colorTV/index.html

[cliffschmidt 0]

People have purchased a DVR rated at 30FPS thinking great this is movie quality! 30FPS divided by 4 channels is 7.5 FPS on each channel. In other words the playback will look more like a series of snap shots rather than watching a movie.

 

This is what has happened to me I don't mind so much. Mainly because the dvr was so cheap and I wanted something simple to start with. I know what to look for now. The main upgrade I'm looking for is in record quality, but I keep finding different ways to measure this. Does anyone know for sure if FPS and PPS and IPS are all the same? Or what PPS and IPS stand for?

[scorpion 0]

There is no way to measure record quality. What you see is what you get.

 

Guarding a residence, and guarding a diamond store, or a bank are completely different situations.

 

How much are you willing to spend? This will be the first way to measure the record quality that you will receive.

 

There are some devices that sacrifice the FPS in order to give you higher quality in record video. This is a fair trade off except where timing is of the essence such as in license plate capture. Low FPS may miss the timing of the plate at the crucial point that would be optimum.

 

For a hospital that wants to catch facial shots of people in an area can have high record quality, and low FPS. The snap shot effect will not create to much of a problem. Very low FPS may create a situation where you might miss a face due to the turning of the face, or a change in the travel path of the person being reviewed.

 

You have to look at what you want your surveillance system to do then you need to select the proper DVR.

 

Residential systems are not "high threat" situations unless you have antiquities, a million dollars cash under the mattress, or jewelry that you need to protect.

 

Inexpensive DVRs can be used. Now it become the lens selection that can make, or break a good system. Most "kits" come with wide angle lenses. Wide angle lenses suffer from distance distortion. At about 20 things in the video will appear farther away then in reality. Faces become smaller in the video, and you have less pixals to create the face.

 

The more you need facial recognition the more you need the video to look like the 6 oclock news with only head, and shoulders in the video frame.

 

Select the right lens, and poor record quality may not be as much of a factor in having a decent system.

[coolie11 0]

Does anyone know for sure if FPS and PPS and IPS are all the same? Or what PPS and IPS stand for?

 

FPS = Frames Per Second

IPS = Images Per Second

PPS = Pictures Per second

 

Have you googled before.

 

Definitions available here:- http://en.wikipedia.org/wiki/Main_Page

[Squiffy 0]

> There is no way to measure record quality

 

Of course there is, with bandwidth expressed in MHz. This can be measured with test equipment and objectively discerned by using a frequency grating pattern on a testcard.

Unfortunately it's not a parameter which seems to be mentioned in most DVR spec. sheets, probably because it would look so disappointing.

[kensplace 0]

You cant really measure image quality properly that way with many DVR's as a still image such as a test card is different from a moving real life image.

 

Moving real life images present different problems for the compression algorithms used in a dvr. A test card may show great, whereas a moving image may not be that good due to poor compression techniques.

[Squiffy 0]

> You cant really measure image quality properly that way with many DVR's as a still image such as a test card is different from a moving real life image.

 

Well you can measure it but I agree that a static image will not give realistic (real world) results because of the compression employed on a moving image.

 

But Snell and Wilcox have moving test card images (for example rapidly moving grating and shapes) which could be assessed for quality and compression artifacts.

[scorpion 0]

The real problem is that they do not sell those cards at Cost Co, Sam's Club ect, and the "common folk" cannot run these tests.

 

I do not know for a fact, but I am willing to bet 90% of the installers in Brevard County do not have a test card.

 

Guilty! I do not have one! I have the manual for one does that count?

 

Hell most of the installers around here do not have a battery operated 4" monitor! I have to have one as this is my main "tool".

[ak357 0]

I do not know for a fact, but I am willing to bet 90% of the installers in Brevard County do not have a test card.

.

 

Do u really want to put test card against AVtech DVR ?

[coolie11 0]

I do not know for a fact, but I am willing to bet 90% of the installers in Brevard County do not have a test card.

.

 

Do u really want to put test card against AVtech DVR ?

 

Sure every installer will love to be able to provide variances of there systems.

 

What do you have in mind?

 

I will love to see a test of AVtech against Kikvision.

[Squiffy 0]

Well I wouldn't expect many to have access to a Snell and Wilcox test card generator unless they're involved with broadcast TV...

 

But manufacturers and reviewers can put DVRs through such tests. As for not having access to test cards and electronic test card generators, the latter are easy to find online for printing out or hooking up to equipment:

 

http://home.tiscali.nl/~peterdb/testcard/

 

http://www.barney-wol.net/testpatterns/testpatterns.html

 

Luminance frequency sweeps and multiburst would be ideal for checking resolution.

 

Worth adding to your tool kits, even if you don't know how to use them it makes you look like you know what you're doing