DVR Video Qualily

[CrimpCap 0]

We've been doing systems for several years. And the last few years we been doing a lot of Digimerge DVR's. I been noticing a huge difference in video quality both live and streaming compared to other DVR's. We recently installed a customers Swann system and noticed the the cameras look so much better live and streaming then most of the Digimerge DVR's.

 

Now I know most of these DVR's are made over seas and are re-branded with the companys name with a nice warranty. But what setsthese DVR's apart? How is it that some DVR's video quality are just better? We know it isnt the cameras themselves being that we have installed higher end cameras on this same DVR with 700 tvl resolutions.

 

Keep in mind there both D1 H.264 recorders.

 

Thank you for any input on the subject.

[cctv_down_under 0]

That is such an open question, there are so many things that affect the quality, however the blue ones are the most likely

 

Starting from the camera itself.

 

 

Light and reflection - often people compare two systems and can not understand how one looks better - often this reason is lighting, for example a white internal floor will often look much better than a similar grey floor, the reflection of light to the camera really makes a huge difference.

 

Lense - Not only the size or f-stop but more important is the transmittion factor of the lens, Ie what elements does it have and how many, are they machined or ground - what abhorations are in the lens, and what is the quality of the glass

 

Camera - soooo many things here

Transmittion media - the quality of cable can really affect image more than you think, high frequency roll off and other issues can occur on poor quality cable

 

Power - yep this can affect image quality - ever noticed that an undervoltaged camera can often be less colourful, less power can = less signal 1vpk to pk is important.

 

Compression - This will be your issue, it is the same as the quality of movies you can download from the net, there are standards, but these are guidelines, not full standards, so one persons H.264 and and anothers could differ greatly in quality and more likely in compression amounts - even if file sizes are the same (similar compression amounts) that does not mean that one compression chip is not better than the other - each chip and hint bridge controller have their own limitations and qualities.

BUS - Some recording devices have a larger BUS speed, this allows for less compression prior to BUS delivery, it is also the reason why PC Based recorders are often faster than purpose built standalones

 

Display Chip - A video system is only as good as the weakest point, sadly often the actual video card used to connect the viewing screen or this chip is not high end, you would not play a nice 3D video game on a PC with a crappy video display chip - so why do it with CCTV.

 

Hardware Overlay and scalling - keep in mind that when a company makes a DVR comnpression chip for analogue it does not make one for NTSC and another for PAL etc, and they are not the same resolutions, so interlacing and hardware overlays are used to adjust so that a single chip could do eiher format, often the interlacing is not done well and requires software interlacing so that you do not experince "video tearing" effect - also it is worth noting that some DVR systems for analogue use a chip for recording and a chip for display, the display chip may have very very limited compression, so this means the DVR looks awesome on live view, but often the recording is much more compressed, some other DVR/NVR's use the same chip or share chips, this means that the viewing is hampered but is a real indication of what you are recording.