S-video over an audio cable?

[Florple]

If you combined the grounds for the y/c signals of s-video, would it still work?
If it would, then i should be able to run it through a stereo audio cable, correct?
This is of course, assuming i would then split them back into two separate grounds at each end.

[mnfreelancer]

There's a concern for shielding on the audio cable. S-Video uses 4 wires typically over mini-coax of some variety where the high-side conductor is in the center and the common is wrapped or braided around it. The industry standard way to extend s-video is to get a mini-DIN (the S-video connector) to BNC adapter that allows you to send the s-video signal down a pair of BNC coaxial cables. I've had great success sending video upwards of 100' this way. I keep a couple of these adapters in my kit and usually have a pile of RGB-HV cable around ("5 wire") on most shows.

[Chris15]

The concern is not the commoning of grounds - that is already happening within the device, but the attempt to send video on an audio cable.

Video wants a coaxial cable of 75 ohms (less fussy in the analog domain, more important for SDI etc.). Audio cable is likely to cause grief to be honest... I'm sure we've discussed it before somewhere around here...

[ruinexplorer]

You are much better staying with video cables for the correct impedance and shielding. Even if everything else is correct in your connections, you may get undesirable results. If you need to extend your run and can't get a cable long enough (up to 50' here or other retailers), you can use an adapter as mnfreelancer suggested. You want to look for something like this or this, but I recommend against converting to composite like this as it can be unreliable (either they fall out too easily or possibly lose chroma). Of course you need to confirm that you don't cross your lines otherwise you won't get a signal at all.