DVR resolution

[mori 0]

Hi every body,

 

i am facing problem that i cant understand in some DVRs there are high resolution such as 7xx*5xx but this DVRs are not D1 resolution as resellers told me. i khnow that D1 refer to resolution 7xx*5xx but i cant understand what exactelly D1 means and when i can say this DVr is D1. could some one exlain this?

regds

[Soundy 1]

D1 refers to the resolution, that's all. D1 is a resolution "spec" of 704x480 for NTSC video (the standard used mainly in North America), or 704x576 for PAL (most of the rest of the world). The other two most common resolutions you'll see are CIF (352x240 or 352x288), and 4CIF (same as D1).

[SEANHAWG 1]

If you are saying that you are not seeing the high resolution during playback then it could be that the advertisement was somewhat falsely advertised. I have made this mistake when we first started buying and testing DVR's myself. We have purchased alot of DVR's and we have seen it all, Here are some things that I look out for now when looking at specs:

 

If the specs dont state it, ask the seller What resolution is each channel recorded at if all 4,8, or 16 channels are recording simultaneously? Some DVR's claim to have D1 Rez but it can only be for one channel recorded at one time. Or they may mean that the D1 resolution is divided up in between all 4 channels which would be CIF for each channel if it is a 4 channel DVR. You will also want to ask what each channels frame rate will be when all channels are recording simultaneously at D1 because quite often it is lower than 30 FPS.

 

One of the worse false advertisements we have seen is they claim to have D1 resolution but that is only for live viewing. During recording it will be something like CIF. That will tick you off.

 

If the sellers cannot answer these questions, then I would move on.

[mori 0]

thank you very much guys, i will check the frame number because i think the game is on that.

best regards

[rory 0]

D1 is a Resolution Standard, in NTSC systems it is 720x480 and in a PAL system it is 720x576. These resolutions come from Rec. 601 and are also used in DVD-Video and Standard-definition television. You will also now see it listed as 704x, something about 8 pixels on each side not containing any useful information so they crop it to save bandwidth.

[danger_e 0]

That sounds about right. Though from what I've heard D1 is 720x480 and 4CIF is 704x480 (in NTSC). The way that it was explained to me is that those extra scan lines are used when transmitting additional information that isn't usually displayed. Closed Captioning in TV transmissions, because while the signal is D1, the monitor displays 4CIF and decodes or dismisses the additional information.

 

Though I'll be honest; I have no way to verify that information and I can't find it on the googles, so I can't vouch for how accurate that is.

[rory 0]

i typically use VGA anyway ... 640x480, cuts down on the image size alot on a Geovision, and less overhead for the PC, without any great noticeable loss in overall quality.