MultiPort and duplicated Images

Forum for questions and support relating to the 1.24.x releases only.
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jriavec
Posts: 10
Joined: Wed Apr 01, 2009 9:21 pm

MultiPort and duplicated Images

Post by jriavec »

Hi, I have a Multi-port PV-981A1-16 card, which supports 16 cameras. I have 12 cameras and I configured all of them as follows...

/dev/video0 channel 0
/dev/video1 channel 0
/dev/video2 channel 0
/dev/video3 channel 0
/dev/video0 channel 1
/dev/video1 channel 1
/dev/video2 channel 1
/dev/video3 channel 1
/dev/video0 channel 2
/dev/video1 channel 2
/dev/video2 channel 2
/dev/video3 channel 2

But it is duplicating the image, if I go to /dev/Video I see only 4 videos so that is why I tried with different channels but it's duplicating the image..

lrwxrwxrwx 1 root root 6 Apr 14 19:38 video -> video0
crw----rw- 1 root root 81, 0 Apr 14 19:38 video0
crw----rw- 1 root root 81, 1 Apr 14 19:38 video1
crw----rw- 1 root root 81, 2 Apr 14 19:38 video2
crw----rw- 1 root root 81, 3 Apr 14 19:38 video3

Could anybody tell me what would be configuration I have to do in order to have my 12 cameras online?

Thanks in advance

Regards

Julian
bb99
Posts: 943
Joined: Wed Apr 02, 2008 12:04 am

Re: MultiPort and duplicated Images

Post by bb99 »

Check the following settings in options::config
ZM_V4L_MULTI_BUFFER

Performance when using Video 4 Linux devices is usually best if multiple buffers are used allowing the next image to be captured while the previous one is being processed. If you have multiple devices on a card sharing one input that requires switching then this approach can sometimes cause frames from one source to be mixed up with frames from another. Switching this option off prevents multi buffering resulting in slower but more stable image capture. This option is ignored for non-local cameras or if only one input is present on a capture chip. This option addresses a similar problem to the ZM_CAPTURES_PER_FRAME option and you should normally change the value of only one of the options at a time.


ZM_CAPTURES_PER_FRAME

If you are using cameras attached to a video capture card which forces multiple inputs to share one capture chip, it can sometimes produce images with interlaced frames reversed resulting in poor image quality and a distinctive comb edge appearance. Increasing this setting allows you to force additional image captures before one is selected as the captured frame. This allows the capture hardware to 'settle down' and produce better quality images at the price of lesser capture rates. This option has no effect on (a) network cameras, or (b) where multiple inputs do not share a capture chip. This option addresses a similar problem to the ZM_V4L_MULTI_BUFFER option and you should normally change the value of only one of the options at a time.
Usually changing ZM_CAPTURES_PER_FRAME to a value of two or three does the trick.
jriavec
Posts: 10
Joined: Wed Apr 01, 2009 9:21 pm

Re: MultiPort and duplicated Images

Post by jriavec »

Hi bb99, thanks for your quick response, more than a software configuration, seems to be a problem with the channels. I used to have 2 PV981A-8A and I had 8 cameras connected to one card and the 4 remaining in the second Card, but we needed to use one of the pci-x slot in the server and that is why we bought the one that supports 16 cameras, but its behavior is like if it only supports 8 cameras. I called BlueCherry and they told me to post in the ZM forum (already I'm not using their software)

Regards

Julian
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kingofkya
Posts: 1110
Joined: Mon Mar 26, 2007 6:07 am
Location: Las Vegas, Nevada

Re: MultiPort and duplicated Images

Post by kingofkya »

did you trey changeing the above variables in the post.
ZM_V4L_MULTI_BUFFER

is exactly what the issues as cased by in every case i have solved.
jriavec
Posts: 10
Joined: Wed Apr 01, 2009 9:21 pm

Re: MultiPort and duplicated Images

Post by jriavec »

Could you please tell me where to find ZM_V4L_MULTI_BUFFER in order to change it.

Thanks in advance

Regards

Julian
PacoLM
Posts: 971
Joined: Wed Dec 02, 2009 9:55 pm
Location: Spain

Re: MultiPort and duplicated Images

Post by PacoLM »

bb69 said it here:
Check the following settings in options::config

After more than 15 years, no longer using ZM as surveillance system.
Now in the dark side, using a commercial system...
jriavec
Posts: 10
Joined: Wed Apr 01, 2009 9:21 pm

Re: MultiPort and duplicated Images

Post by jriavec »

Thanks, I do have the option V4L_MULTI_BUFFER checked and in the CAPTURES_PER_FRAME is already in 3.

what do you suggest?

Thanks in advance

Julian
bb99
Posts: 943
Joined: Wed Apr 02, 2008 12:04 am

Re: MultiPort and duplicated Images

Post by bb99 »

Uncheck V4L_MULTI_BUFFER and save, then restart.
jriavec
Posts: 10
Joined: Wed Apr 01, 2009 9:21 pm

Re: MultiPort and duplicated Images

Post by jriavec »

Hi, I unchecked the option, saved it and restart the ZM but it still is showing duplicate images.

as I said it seems to be more a problem with the channels or the card itself.

Regards

Julian
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