Cctv Video Samples Needed

[Ish]

Hi

Has anyone got any links to video samples of cctv footage at different fps ie 5,10,15,20 etc.

It only needs to be short clips to allow us to see what the difference in quality is at different fps.

Thanks

[Guest]

Think the Data protection act will not allow us to show stuff.

Why would we keep coverage on our pooters anyways, have a view of every install, but its kept on file under lock and key.

I think your wondering about the "capture" rate, 5 fps is fine if you like watching skippy do a dance i generally use 12.5 fps as its good and makes the HD last longer.

[secboy]

Hi

Has anyone got any links to video samples of cctv footage at different fps ie 5,10,15,20 etc.

It only needs to be short clips to allow us to see what the difference in quality is at different fps.

Thanks

You may have a problem with this request Ish coz the video quality is composed of more than just frames/sec--so the multiple computations of the video structure make it very difficult to give examples.

Paul.

[arfur mo]

You may have a problem with this request Ish coz the video quality is composed of more than just frames/sec--so the multiple computations of the video structure make it very difficult to give examples.

Paul.

Hi paul

to put another way for Ish, intellegent frame rate allocation on older vcr/mux system was called 'interleaving', it means more frames are taken on active camera's than inactive ones to give better images, the rate is automatically handled by onboard application software an incorporated in modern DVR's.

so as it's a veriable frame rate it would be dificult to give example's. the engineer can fine tune settings to give precedence to more critical camera's, so you can use this to overide and force frame rates, then do samples say of your dancing skills in the car park - and post them here for us to compare

regs

alan

[secboy]

Hi paul

to put another way for Ish, intellegent frame rate allocation on older vcr/mux system was called 'interleaving', it means more frames are taken on active camera's than inactive ones to give better images, the rate is automatically handled by onboard application software an incorporated in modern DVR's.

so as it's a veriable frame rate it would be dificult to give example's. the engineer can fine tune settings to give precedence to more critical camera's, so you can use this to overide and force frame rates, then do samples say of your dancing skills in the car park - and post them here for us to compare

regs

alan

Nice one allan! I know wot I mean but cant put it across as well.

Paul

[Guest]

Why not set up a test bench, then play with it.

Its good fun and ya can work out everything b4 you have to show the end user stuff.

[Service Engineer]

http://www.indigovision.com/site/modules/W...rame%20Rate.pdf

The natural full frame rate of an interlaced camera is fixed at 25fps for PAL cameras and 30fps for NTSC. Encoders, such as the IndigoVision VB8000 MPEG-4 motion-based encoder, can compress full frame rate video through a process of removing the unnecessary information that exists within each individual frame of video, but that also exists over periods of time, such as a static background. Other types of encoder, such as an MJPEG stills-based encoder, remove only the unnecessary information within each individual frame of video, regardless of the information that has already been transmitted by previously compressed frames. Altering the frame rate will affect both types of encoder.

As the frame rate increases, the bitrate increases for both encoders. At the lower frame rates the difference is the order of 100kbps. However, as the frame rate increases the motion-based encoder always produces increasingly fewer bits for the same quality of video, than the stills-based encoder, to the point that at 30fps the difference is of the order of 1.5Mbps! This can be explained simply as the static background parts of the video remain static for long periods of time. This means that, even at the lower frame rates, the motion-based encoder can work with only a slight reduction in efficiency.

Motion-based encoders, like MPEG-4, will outperform stills-based encoders, like MJPEG, in terms of either video quality or bitrate, as they always have an option to make use of any similarities that exist over time, be it static background or coincidentally matching data. Reducing the frame rate simply reduces the probability of the motion-based encoders finding similarities and thus being less efficient. However, it will always be better than not trying at all, as with stills-based encoders. Conversely, increasing the frame rate increases the probability of the motion-based encoders finding similarities and thus being more efficient. In a CCTV scenario it has been shown that increasing the frame can lead to a 11-fold increase in bitrate with a stills-based encoder, when compared to a less than 5-fold increase with a motion-based encoder. Furthermore, that even with very complex, high motion video not found in CCTV applications, that the relationship, if not the degree, remains true.

[Guest]

I am the David Bailey of cameras, trust me i know nothing.

All i do is set up the bastids, and point them where the customer wants, and hook up the DVR.

I use tech support for probs, oh the joys of being employed........

In defence of the above statement, i have some pretty good installs which recordings taken have stood up in court as evidence.

[Ish]

Hi All

Thanks for the replies but I think i better give you a better explanation.

We had a quote for a cctv system which included a geovision pc based controller. When we asked for a sample of what the quality of the recordings would be when we played back we were told they would be fine but the company could not provide a sample!

We just want to be sure we are going to pay for something that is suitable for our needs so I suppose what I really should have asked is on a Geovision system what kinds of FPS should it be recording at so that when we playback footage it doesn't skip around

I have seen 12.5 FPS mentioned above. Is that ok?

Thanks

[Service Engineer]

I have seen 12.5 FPS mentioned above. Is that ok?

That's Fine, I only record at 2 FPS at home and results are decent quality recording and longer recording times.

How many cameras are being recorded and how many days continuos recording do they want.?