Ynot Posted May 3, 2012 Share Posted May 3, 2012 Quick question about using a video/TV card to accept a composite signal... I have in front of me an in-line adaptor that has been sitting in my drawer for years, unused.I now have a possible little job for it - I have a small footprint PC into which I want to fit a TV/video input card (the Hauppage WinTV type of thing) but the smaller PCI Express cards that I'm looking at don't appear to have the composite yellow phono input that the larger full size PCI cards have, though both have an S-video socket. So the question is for those in the know - can I simply plug the phono feed via this adaptor into the S-Video in socket...?? This is for feeding the show relay camera signal to the bar and through that to the distro for the rehearsal rooms, so quality isn't paramount. Link to comment Share on other sites More sharing options...
timsabre Posted May 3, 2012 Share Posted May 3, 2012 The adaptor will be to convert an S-video output to a composite video output by combining the luma and chroma using a couple of caps and resistors. It won't work backwards to separate the luma and chroma. You will get a black and white picture if you use it, which might be acceptable for your application? Link to comment Share on other sites More sharing options...
Ynot Posted May 3, 2012 Author Share Posted May 3, 2012 Just shows I know squat about S-Video!!;) Never heard of the luma and chroma, so hey ho. B/W isn't really ideal - guess I'll start looking again for a low profile Hauppage card... Link to comment Share on other sites More sharing options...
pjb304 Posted May 3, 2012 Share Posted May 3, 2012 My understanding of it is that S-video gives higher quality than composite by sending the brightness (luma) and colour (chroma) seperately, which means there is a higher overall bandwidth available. One thing to be wary of is latency. We've tried a usb haupage video capture card (which offered s-video input) which was fine quality wise, except there was about a 2 second lag on the image updating. This made it unusable for the application we had in mind, but for a bar feed might be acceptable. Link to comment Share on other sites More sharing options...
Shez Posted May 3, 2012 Share Posted May 3, 2012 I've seen those adapters advertised as being able to work both ways; never tried using one though. Luma is the brightness information (essentially a black & white signal) and chroma is the colour. There's nothing clever about splitting or combining them; the colour information just works at a higher frequency so splitting them is like a passive loudspeaker crossover. Combining via summing resistors should work in the same way. Link to comment Share on other sites More sharing options...
henny Posted May 3, 2012 Share Posted May 3, 2012 Take a look at the s-video connection on the card . Some have more than 4 pins they will accept a std s-vid cable but then come with an adaptor for comp that uses Some of the other pins Link to comment Share on other sites More sharing options...
AHYoung Posted May 3, 2012 Share Posted May 3, 2012 the adaptors will work both ways, for years one has been feeding composite video into the svhs input of a projector with a broken composite input, its not totally transparent, but it works well enough , from memory the thing only cost a couple of quid so its worth a try,,, if colour pictures isnt important, just feed the composite video into the luminance input using a 4pin mini din - dual phono breakout and it will work fine, just in glorious greyscale. Link to comment Share on other sites More sharing options...
timsabre Posted May 3, 2012 Share Posted May 3, 2012 the adaptors will work both ways Well I learn something every day on this forum. At some time in the distant past I have had one of these that only worked one way, but maybe it was faulty or cheap and nasty. Link to comment Share on other sites More sharing options...
Ynot Posted May 3, 2012 Author Share Posted May 3, 2012 Well, tried it on another PC with TV card this evening, and yes aI get a nice black & white picture... Link to comment Share on other sites More sharing options...
Shez Posted May 3, 2012 Share Posted May 3, 2012 It's worth checking any available settings in the config utility for the capture card. Many moons ago when I built my first PC I put an ATI all-in-wonder pro capture card in it - there were plenty of settings to get wrong in there. I've since had dealings with other video capture cards that were similarly difficult / unreliable. Maybe things have improved since then of course. Do you have any other equipment with an s-video input you can try the adapter on? TV / projector etc. Something just to prove it's working or not. Link to comment Share on other sites More sharing options...
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