Noise lines during capturing

Ciccio · Post by **Ciccio** » Tue Sep 06, 2005 11:09 pm

I installed latest MDK LiveCD with a one Conexant chip and 4 inputs capture card.
If I see monitor in higher resolutions (surely >=640x480) in RGB* mode I got a lot of noise horizontal lines when ther's movement in the image.
It's a Zoneminder fault cause I get an excellent image if I look it at 640x480 or more with xawtv (or tvsomething can't remember well).
Setting grab image to 352x288 or less I don't get any artifact.

What could cause the problem? I get those lines even in stil frames so it's as zmc can't capture correctly frames at those resolutions.
Machine is a P4 2.4 Ghz with 512 MB Ram and I'm usting it with only one cam so I don't think it's a load problem (load is variable from 0,5 to 1.2, with X running).

Francesco

jameswilson · Post by **jameswilson** » Tue Sep 06, 2005 11:24 pm

xawtv, tvtime etc use deinterlacing techniques to stop this happening.
This is a common question use the search the fourum buttin and search for interlace
http://www.zoneminder.com/forums/viewto ... =interlace will get you started

Some chips are better than others but if you are getting 'combing' even without movement, lazyleopard wrote a nice mod that phil added in 1.21.3
The setting is in options somewhere

James

Ciccio · Post by **Ciccio** » Tue Sep 06, 2005 11:53 pm

Thanks I've founded that options and I'm updating zm (I had 1.21.0), I tried to search on forum but I didn't know how this effect was called.

Try to solve with this options and let you know...

jameswilson · Post by **jameswilson** » Wed Sep 07, 2005 12:01 am

i have just seen the picture from your first post dont know how i missed it. Unfortunatly what im talking about wont help. That looks like a hardware problem in the camera. Have you tried pluging it into a std monitor?

James
ps sorry for the wrong info i gave ya

Ciccio · Post by **Ciccio** » Wed Sep 07, 2005 2:03 am

As I told in the post the problems doesn't occurs if I see images in tvtime: I got a fluid full framerate video without artifacts. But when I go in zm that's what I got around "moving" objects if resolution is more than 352x288.

Ciccio · Post by **Ciccio** » Wed Sep 07, 2005 11:13 am

Tried upgrading to 1.21.3 and using that options but nothing changed. I'll try changing my cable/videosource.

Post by **zoneminder** » Wed Sep 07, 2005 11:31 am

As I've just mentioned in another reply strangely enough, xawtv etc in normal mode just use a memory mapping technique to map the video memory to screen memory. In order to analyse an image ZM (and other applications) have to grab each frame separate using a different method. In xawtv you can simulate this by doing a few image/frame grabs and saving and examining those images.

I would be interested to see whether any of those images exhibit the same problem. A couple more example images might also be useful.

Phil

Ciccio · Post by **Ciccio** » Wed Sep 07, 2005 12:21 pm

I did as you said, grabbing some images with tvtime and I got these results:

and

So none of those strange lines appears here.
Hope to be useful to you to understand some more than I do!

Ciccio · Post by **Ciccio** » Sat Sep 10, 2005 12:27 pm

I didn't still solved but I'm now trying to see if it happens with a different bttv grab card (It's a TV Card I've got). Let you know soon.
Phil as you see with tvtime I don't have such noise, have you got some idea about that problem? It's something only I have to fight with or you already had seen something similar?

Ciccio · Post by **Ciccio** » Sat Sep 10, 2005 1:02 pm

I've found some more info about the card I'm using. It's a Hawell DVR Card Hw-104, you can find some specs here:
http://www.alibaba.com/catalog/10985937 ... w_104.html

I tried using 768x288 and lines disappeared. So that problems seems visible when vertical resolution is > 288... (as you can see in screenshot they appears only in the first half of the image, never below, I forgot to say this particular in my post).

RedFlyer · Post by **RedFlyer** » Sat Sep 10, 2005 1:41 pm

Hi,

This card is also known as PICO2000. They are lot of clone all over the world

Why do you want to use it in a resolution higher then 384*288 ?
Personnaly, for CCTV it's more than enough.

Regards,

Oliver
________
Mercedes-Benz 200 History

jameswilson · Post by **jameswilson** » Sat Sep 10, 2005 3:54 pm

i would like to capture above that res for number plates recognition etc i am looking at going the ip route to achieve this

James

Ciccio · Post by **Ciccio** » Sat Sep 10, 2005 6:28 pm

jameswilson hit the point!
I need to have enought resolution to make plate recognition (manual looking at events and when I'll find a software I can use with zoneminder by sw).
Maybe the card isn't the best choice and maybe I'll change it but I'd like to use all its potential before trashing it!

jameswilson · Post by **jameswilson** » Sat Sep 10, 2005 10:10 pm

i think if you feed progressive scan into it you should be ok. I am supposed to be testing this. Else go for IP camera. Im gonna trial a 206M to see how megapixel performs as i think this is the way to go. Unfortunatly is zm is analysing images of this size i think the overhead maybe too high. Someone else came up with the grat idea of sampling down to a low res just for movement analysis. If Phil impliments this then this will without doubt be the way to go.

James

jameswilson · Post by **jameswilson** » Sat Sep 17, 2005 12:11 pm

I have just gained another old machine and am having this problem now. What mobo u using?