Take the 2-minute tour ×
Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Hi Im looking for a cable to connect my PC with VGA output to my tv which supports S-Video and Scart input. I thought this would be a simple task however when searching I came accross forums saying that its not so simple, you need the right cable or that it doesnt work. I know that alot of it is conjecture but it has made me not very confident in what lead to get.

Would a simple cheap cable like the following be fine? http://www.amazon.co.uk/VGA-to-S-Video-RCA-Adaptor/dp/B000P3UB24/ref=sr%5F1%5F1?ie=UTF8&s=electronics&qid=1259616483&sr=8-1

Also would I need to do anything special once I hook it up? I know that I need to set the PC resolution to something that the TV will support.

Any advice greatly appreciated!

share|improve this question
add comment

1 Answer

I had this problem too. What I concluded is that it is NOT generally possible with a simple cable. The VGA signal from the graphics card is not compatible with ordinary TV input formats. The VGA signal is an RGB-signal with separate horizontal and vertical synchronization clocks (RGB-HV).

Although SCART does support RGB, it uses a single synchronization channel, where both vertical and horizontal clocks are transmitted using the same lead. Additional circuitry is required to combine the H and V sync clocks of the VGA output into one composite sync clock. Even then, TVs require very specific resolution and sync frequencies to show the image. These are not impossible to output by your graphics card, but are not standard and require manual configuration. If your card cant do it, some form of re-sampling device will need to be used (which will reduce quality).

S-Video and YPbPr-component inputs on your TV are completely different from the RGB output on the VGA-card. They use separate luminosity (Y) and two color channels - Pb and Pr (aka U and V). In case of s-video the two color channels are combined into one. This is done because luminosity carries much more information useful for the human eye, so it pays much more to preserve the quality of the Y-channel than the color channels. So s-video is not even close to be compatible with VGA.

Either way you will need additional electronic equipment to convert the VGA-signal into one supported by your TV (there exist devices that can do that, with varying quality of the result).

There are two exceptions:
- Some (most) graphics cards come with such a device built-in and offer a s-video output port.
- Some new TV:s support the VGA input directly, in which case you can use them as ordinary computer screens, with a simple VGA cable (D-sub 15, both ends male).

This link describes probably the most minimalistic attempt to a VGA-SCART converter (it only combines the H and V sync clocks into one, the correct resolution and frequencies are up to the VGA card): http://www.epanorama.net/circuits/vga2tv/index.html

As to the link you refer to, the product description specifies:
"NOTE: Your VGA card must support TV out directly through VGA port function. Please consult with your VGA card's user manual for more information.".
This means that the cable is a simple connector adapter. In order for it to work, your card must have a built-in s-video or composite support and use the VGA-connector instead of the usual mini-Din/RCA connector. Consult the manual of your VGA-card/laptop if s-video/composite output is supported through the vga port. If it is, it should work. You might still need to choose appropriate (low) resolution.

share|improve this answer
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.