I can't even watch keyboard cat...

September 29, 2009 3:39 PM

Laptop to HDTV with a VGA-to-SVideo adapter: Why doesn't it work?

I want to connect my Linux Eee PC to a 720p HDTV. To do this, I'm trying to use a cheap VGA to S-Video adapter, but the TV receives no signal and I've tried all the VGA out resolutions with xrandr. Unfortunately, I didn't notice this stipulation on the Newegg product page:

This adapter works with graphics cards that have TV-Out function capability through the VGA connector.

I've never heard of TV-Out through VGA. How can I tell if my Intel 945GME chipset supports it? How would I tell xrandr to use it? I would really like to not have to buy an expensive converter box.

posted by qxntpqbbbqxl to computers & internet (12 comments total)

First question: does your 720p TV have a VGA input? I know it sounds silly, but many of them do, and it'd make your job a lot simpler.
posted by DMan at 3:44 PM on September 29

Those $2 adapters? Yes, those are only for VGA ports that are already putting out TV signal. Most don't, as you noticed, and the EeePC doesn't seem to do it.

EeePC forum on the topic.

Maybe your HDTV has an SVGA input or "computer" mode that does the conversion? Some do.
posted by rokusan at 3:48 PM on September 29

Your video card doesn't support this. If it did you'd know it. Specifically, I know the eee pc doesn't supprt this in any known flavour of the device. s-video and VGA connections have no similarity in terms of signal format other than they're both for video.

Your best bet is to check your TV for VGA-in.
posted by GuyZero at 3:49 PM on September 29

Unfortunately, no VGA or DVI input.

HDMI, S-Video, and component.

Does anyone know if a VGA to component adapter will have the same problem?
posted by qxntpqbbbqxl at 3:49 PM on September 29

BTW the adapter you have is for very specific VGA cards that are re-using extra pins on their VGA connector for a s-video signal they're already generating. This is really, really rare and not really standards compliant. If your video adapter supports s-video it almost always has a s-video port.
posted by GuyZero at 3:50 PM on September 29

Something like this converter is pretty much your only choice if your TV doesn't have VGA-in.
posted by kmz at 3:56 PM on September 29

This VGA to HDMI adapter, while a bit more expensive than the VGA to S-Video adapter linked above, will result in a much, much better image.
posted by zsazsa at 4:07 PM on September 29 [1 favorite]

Thanks for the links to the cheaper converter boxes.

I guess I'll go for the HDMI box, although all of those boxes appear to support only 4:3 aspect ratios so I'll have to do some creative aspect ratio manipulation.
posted by qxntpqbbbqxl at 5:11 PM on September 29

I'm not sure the vga to hdmi adapter would provide a better signal than vga to component. The signal is coming out as VGA (analog) then being converted to digital and transferred to the TV. I guess you have the advantage of the signal not being lost in long cables, but, uh, just use shorter cables.

VGA and Component (R/G/B, as opposed to Composite, Yellow (white and red are audio)) are essentially the same signal, just in different configurations. An adapter isn't really doing anything but changing the shape of the plug, much like those foreign power adapters that dont stepdown voltage, just let you plug in your device.

Here is one for two dollars. I'll give you two dollars if it does not work!

Addendum: TV resolutions are very specific. The PC must be able to output the right refresh rate / timings / resolution. But, I think the EEE PC can! It's worth a shot.
posted by CharlesV42 at 5:18 PM on September 29

HDMI is backwards compatible with DVI - could try a VGA-DVI-HDMI daisy chain.
posted by squorch at 5:28 PM on September 29

OP: Before you shell out the $2 for the VGA -> HDMI adapter CharlesV42 suggests, don't miss this tidbit from the item description:

"THIS CABLE WILL NOT ALLOW YOU TO CONNECT YOUR COMPUTER'S VGA PORT TO THE COMPONENET (sic) INPUT ON YOUR HDTV unless your video card supports component out function through it's VGA port (please confirm with your video cards documentation before purchasing)"

I looked at that same adapter to do exactly what you're trying to do, and that sentence scared me away. If you actually get this to work, please let me know!
posted by harkin banks at 11:11 PM on September 29

Follow-up:

A converter box is necessary. Analog adapters will not work unless the video card can output component or s-video through VGA (most cannot).

Even with a converter box, you're only going to get 1024x768 --- I couldn't find any that would go higher, which seems like a real waste for a HDTV since you don't even get the right aspect ratio.

I returned the TV and bought a different one that had a VGA input, works great.
posted by qxntpqbbbqxl at 5:58 PM on October 31