svideo bnc trouble

[Liam Vink]

i've got an old hard drive based cctv recorder that i need to get footage off.
it has bnc outputs that seem to convert to composite video and are received by a tv so you can veiw the stream from the cameras, but when i tried to hook it up via a pci tuner card with svideoin-composite converter all i got was black and white mess. in effect I was going from It was bnc to svideo, and i assume because of the composite cable involvement there are only 2 wires making full connection throughout this 'cable'
different computer apps/decoders didn't solve the problem. is it something to do with the load on the cable from the bnc output that a normal tv can deal with but a pci card isnt designed to handle?
Will I be able to pick up the signal via the rf aerial input on the card?

Though the hard drive is IDE can't be read by a normal computer i assume non-standard format.

thanks

[Chris Soucy]

Welcome to DVinfo.

Er, I think I managed to decode your post, tho' maybe not.

Do I take it you're taking a feed from a BNC composite O/P and sticking it into a S - video input on your tuner card?

Er, nope, read it yet again and now I'm not sure.

Think before I dig myself a hole, I'll let you assure me you're not feeding composite into s - video, 'cause if you are, it won't work.

Going back to first principles for a moment, have you tried using a bnc to whatever connector cable to feed this signal into a screen, any screen, that has composite input - monitor, telly, anything?

Every single screen in my house will accept composite, usually on a RCA socket, yours should be the same.

If you try it and get a decent picture, you don't have a dead box or cable.

Think we better start from there.


CS

[Liam Vink]

sorry chris it does seem a bit confusing now i read it.
ok i have a cctv box with bnc inputs and outputs. those outputs have bnc to composite adapters on them because obviously no one uses bnc anymore. these adapters accept composite cables from the cameras. there is a 'monitor' bnc output with converter that feeds via rca into a 14" tv and you get perfect picture, etc. i have a pci tv card with svideo input, thqat came with what looks like a composite to svideo cable (i researched and it looks like it just bridges the chroma/picture pins into 2 channels). When i connect the composite feed from the cctv i get a garbled picture.

I'm taking the pci card back and getting one with direct composite input in the hopes it solves the problem
cheers

[Liam Vink]

oh if this helps
the picture i get onscreen when i first start the computer app after connecting cctv is a scrambled black and white freeze frame, even though its a live colour feed from the cameras in reality. I was thinking this might be because somewhere between the cctv and my pc the signal is getting mixed up, i.e losing some kind of 'sync' signal and 'colour' signal becuase of too many adapters being used

[Liam Vink]

and when i was in another retail store the other day i saw similar cables with adapters feeding from the stores cctv cameras into a single computer - which had a card with one input that looked like a massive maybe d-sub or scsi socket and all these composite leads feeding into a plug in that socket so maybe i'm barking up the wrong tree with trying to shortcut using a tv card

[Chris Soucy]

I think where it's all going down the gurgler is that "composite to s - video" cable/ adapter thingy.

If your card want s - video, s - video is what you must feed it and you can't generate s - video from a composite source using just a cable.

The "composite" connectors you mention are most probably RCA/ phono (take your pick) and are just a different connector for the same type of signal.

If you have a camera with both rca video and s - video connectors (like a Canon XL1s) you could take the composite into the camera and see what appears on the s - video connector.

It would be great if it O/P'ed what it saw on the RCA input, but I have a feeling you might have to tape it and play it back out through the S - video port.

If you're replacing the card with one that has composite I/P I think it should be "job done".

Good luck.


CS