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RCA Composite -> CVBS

Posted: Mon May 24, 2004 12:14 pm
by Jimmy
Could someone explain to me what the differences are between composite RCA and CVBS, and what is involved in converting from the one format to the other?

I have already tried a search on google and there is very little information to be found, I am interested from the point of view that some of the professional TV input cards available have this funny CVBS plug connector and I'm not sure how you could interface several CCTV cameras with it.

Also, would a BT card with 16 composite inputs work with Zoneminder? Is it able to support that many?

How does it discover the device? Is each on board BT chip seen as a separate device entry in /dev ?

Thanks for any information.

Jim

Posted: Mon May 24, 2004 12:15 pm
by Guest
16 inputs via the CVBS plug that is (just to avoid confusion)

Posted: Mon May 24, 2004 12:15 pm
by Guest
would the inputs on a CVBS plug appear as Composite0 Composite1 etc

Posted: Mon May 24, 2004 5:12 pm
by Jimmy
right I think I've figured this out, there's no actual conversion needed, it's just a cable connection from RCA > CVBS bus style connector.

However I'd still be interested to know how a device like this appears logically. Do they appear as Composite ports like in a standard TV card i.e. /dev/video0 Composite0....Composite4

Anyone have any ideas?

Thanks

Jim

Re: RCA Composite -> CVBS

Posted: Mon Aug 30, 2004 10:45 pm
by Doug
Jimmy wrote:Could someone explain to me what the differences are between composite RCA and CVBS, and what is involved in converting from the one format to the other?

I have already tried a search on google and there is very little information to be found, I am interested from the point of view that some of the professional TV input cards available have this funny CVBS plug connector and I'm not sure how you could interface several CCTV cameras with it.

Also, would a BT card with 16 composite inputs work with Zoneminder? Is it able to support that many?

How does it discover the device? Is each on board BT chip seen as a separate device entry in /dev ?

Thanks for any information.

Jim
I don't know about the RCA/CVBS but it sounds like you figured that out.

Looking at ZoneMinder, it really doesn't care much about your hardware since it relies on drivers to handle that. In your case, and mine, that's the bttv driver which detects the chipsets and tries to figure out the device capabilities. My bt878 board gets detected fine with /dev/video0 created and by selecting channels 0, 1, 2, 3 off of /dev/video0 in ZoneMinder, I can get all 4 inputs. If you've got a card with 4 bt878's then I would guess that you'd get 4 devices( video0, video1, video2, video3 ) created and access each fo the 4 channels on those devices as I mentioned.

I hope this is helpful.