3.5mm headphone jack -> component video?

"3.5mm Jack can be a bit strange. If you noticed, some of them have different numbers of black stripes on them. 1 stripe for Mono-Audio, 2 stripes for Stereo-Audio, 3 stripes for Video + Stereo-Audio (rare, and usually usable only for specific devices).

I had one with 3 stripes for my D90, which enables direct playing of Video / Images from the camera directly to TV (the other end is RCA jack).

Although the physical cable supports transmission of Video Signal, but normal headphone jack on your PC/Mac will only supports sending Stereo-Audio as they are designed for."

"Like several have said: it's a no-go to get video out of that custom cable. It's just not going to happen.

Here is your best bet to get composite video out of your Mac:

Apple DVI to Video Adapter"

"To my knowledge, the Mac does not support video out via the headphone jack.

However, video iPods (but not iPhone or iPod-Touch) do support sending composite video out the headphone jack (and doc connector audio port) using the cable described.

Due to having to support headphones and video over the same jack the pin outs are non-standard. Swap the red and yellow connections on the TV to get correct video and stereo sound. (Cables purchased from Apple for this purpose are marked correctly for the iPod.)"

"Some Macs - at least a couple models of iBook - have supported video output over the audio port.

However, Apple does note that all video-over-phono-jack cables are non-standard:

[third-party] cables are not interchangeable with the Apple A/V cable for use with the iBook (FireWire) or iBook (Dual USB). Using a third-party cable with these computers will likely result in a distorted audio signal and no video output to the external monitor.

If you got the cable with a third-party device, and it didn't come in the same box as your Mac, there's probably nothing you can do to make it work."