What happens to the extra pixels?

[habarraclough 0]

When you have a camera that's rated at 600tvl (811x508p) or 700tvl (976x582p) and a DVR that can only record at D1 (704x480p), what is the actual resolution/size of the image being being recorded? I know that the high resolution cameras look great on the monitor, but playback can only be at the lower resolution because that's all that it is possible to record.

 

What happens to the "excess" pixels the camera is sending to the DVR? Is it true that any camera over 540tvl (768x494p) is a waste of money because of the limitations of DVRs?

 

Can someone who really knows explain this please? I don't need responses touting IP cameras and megapixels at me, - I'm trying to understand the hand I've been dealt and not the one I wish I had.

[Nimrod 0]

“What happens to the "excess" pixels the camera is sending to the DVR?”

 

Well the simple answer is, they are not there. The pixels are at the sensor of the camera after some processing that digital signal is converted to analog, this conversion process looses some resolution. The image is now in a analog domain and pixels no longer apply. The analog signal goes to the dvr input, on the way is goes through some wire, the longer the wire the more resolution you slowly loose. The dvr input has a low pass filter to reject noise, this causes a little more loss of resolution. The analog signal is now reconverted to digital, causing a little more loss. At this point there is something called bit rate sampling and it has a large effect on resolution.

 

With all of this said and done the pro’s on this forum state you only have 480 lines of resolution left after recording (analog resolution is measured in tv lines) .

[habarraclough 0]

Thanks for the great explanation! Understandable and concise and non-judgemental, - I really appreciate it. You've confirmed what I suspected happened, without my knowing all the technicalities of how it happened.

Thank you again.