Zoneminder and multichannel cards

Mark Tinguely tinguely at
Fri Oct 5 06:07:54 PDT 2007

Achilleas Mantzios asks:

>  I dont know if you are familiar with zoneminder,
>  it has a capture daemon (zmc) which is used to grab the video.

There are several clone simular to that card.

>  In the installation we have at work under linux, using a 4-chip board=20
>  (LMLBT44), i can see that there are only 4
>  instances of it (zmc) running=20
>  on /dev/video0,/dev/video1,/dev/video2,/dev/video3
>  to capture all 8 cameras.
>  This board supports 4 full rate inputs, or 8 multiplexed inputs.
>  So for each one of the 4 chips, the corresponding zmc daemon is used
>  to simultaneously capture both channels (cameras) of the same chip.
>  Theoritically is that possible with FreeBSD's bktr driver?
>  Could we have an app like lets say xawtv to display all (4 in my case)=20
>  channels of a multiplexer board like LMLBT4M which utilizes only one 878 ch=
>  ip=20
>  and supports 4 multiplexed channels i.e. 4 cameras?
>  If your answer is yes, then i should keep on trying with=20
>  =46reeBSD/ZoneMinder/zmc, etc...
>  Else i should buy 3 additional bt 878 cards, or switch to linux which i wan=
>  t=20
>  to avoid!

No matter the OS, a BT878 can capture from one video input AT ONE TIME.

The LMLBT4M has only one BT878 video capture chip. A person can write
a program to capture images from up to 4 inputs using time division

As you said there are cards with multiple BT878 that are either dedicated
to one input or allow multiple inputs. For example, the Kodicom 4400 (and
clones) have 4 BT878 capture chips and a crossbar that lets a person choose
from 16 inputs (on at a time per capture chip). I have a patch (see last
week's archive for thread) that sets up the crossbar on the Kodicom 4400.
There is also a Kodicom 8800 (and clones) with 8 BT878 capture chips which
I have not used.

--Mark Tinguely.

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