Dvr Recording Resolution

[StuBoy]

New to CCTV.

I'm in the process of putting together a CCTV system ... of up to 8 Cameras and plan on using mainly 480 TVL Cam's ... may also have one or two 500 TVL Cams using the new Sony HQ1 Chip.

Based on going for high-res cams ... I'm not sure what DVR I should go for.

I'd like to ensure good clear quality images hence the choice of Cams.

Would I benfit for going for a DVR capable of 720 x 576 (as opposed to the 730/704 x 288) ?

I have been looking at the following DVR's any comments / recommendations

SystemQ SMART2 720 x 288

SystemQ Pro DVR365 352 x 576 or 704 x 288

XVision WDVR8 720 x 576

Want a DVR that will record at good resolution, is it just a waste paying for 720 x 576 resolution with 480TVL Cams.

Also any comments on whether JPEG2000 or MPEG4 is the way to go.

[Guest Director of COP Security]

The big problem in answering your question is that there is more to quality than resolution.

The resolution 720 x 576 (D1) is the equivalent to the resolution you get from a DVD, however there are three other factors that affect the "quality" of the recorded images.

A big factor is the compression method, M-Jpeg and Jpeg 2000 use a method that in simple terms takes a single still image and then compresses it, this is repeated many times to get a moving image, the results can be very good but the frame rate is limited on systems over 4 channels. MPEG4 is a much better compression method for moving images (SKY use it) as it uses clever software to predict that changes will be in the next frame and only store the changes. This is a much simplified explanation but the generalisation means that M-JPEG and JPEG2000 produce much larger files for the same length of video.

The second big factor in determining the recording quality is the compression settings, sometimes called "Quality" in the DVR. These can make a huge effect as a low "Quality" setting can use as little as 1/8 of the space of a high "Quality" setting. In general the higher the "quality" setting the less the pictures will be compressed, but the more HDD space will be used.

The third factor is the internal settings that the factory have used in there implementation of the compression method. Although people quote MPEG-4 or JPEG2000 etc they are all modified versions and are tailored to each type of DVR. So even with the resolution and "Quality" settings programmed the same on two different types of DVR the results may be totally different.

Ok so what do you do?

I would recommend the following:-

1: Use the best cameras you can afford for the Job, the old saying is true (garbage in garbage out)

2: Go for a MPEG4 DVR if you are going to use frame rates above 5fps per camera as this will give better results.

3: Get hold of a couple of DVR's you are interested in, and then compare the results with different settings. You may be surprised that a resolution of 320x 288 running at a high frame rate in high

[cutwitt]

Agree with the above, stick with good quality cameras for clear images.

Latest implementation of mpeg4 is H.264 - attempts to get image quality close to jpeg2000 but with much reduced file size so recording times are much longer. Also possible to get an H.264 machine that can record all channels at D1 realtime (25fps) for many days on a big drive see

here

would not normally recommend PC based DVR but had a look at one of these recently and was most impressed.

[Guest walter]

Agree with the above, stick with good quality cameras for clear images.

Latest implementation of mpeg4 is H.264 - attempts to get image quality close to jpeg2000 but with much reduced file size so recording times are much longer. Also possible to get an H.264 machine that can record all channels at D1 realtime (25fps) for many days on a big drive see

here

would not normally recommend PC based DVR but had a look at one of these recently and was most impressed.

your camera is very good,

Refer to DVR,YOu can choose GE 8channel DVR.

Mjpeg will let you get better picture than Mpeg4 or 264.

If you need net browsing,Mpeg4 will be well and cheap!

[cutwitt]

"your camera is very good"

What camera?

I could put a Sony HQ1 chip in a biscuit tin with a jam jar lens but it won't make a good camera.