Having Trouble with VGA-to-RCA on my Dell M1530

[cannedpeahes]

I recently bought a VGA-to-composite adapter for my Dell M1530 laptop so I could connect it to an old RCA-made tube TV that I just bought at a steal from a friend. All I was looking to do was have an HTPC so I could watch some DVDs, maybe play a little (crackly, low-quality) music.

I plugged in the RCA adapter and all the composite cables to both the TV and laptop, but there was no result, even when I pressed Fn+F8 (Dell's "CRT/LCD" switch). I went into the nVidia Control Panel (the machine runs on an 8600M) and set it up for multiple displays using Dualview, even making the primary monitor the old TV. I set the resolution of the TV-Out to 640x480 (the closest a computer can come to NTSC, I think) and the refresh rate to 60Hz.

Still, the only effect it had was to produce a little crackly noise and a slight flicker on the TV, but it went right back to a black screen.

Any ideas?

[Fail Medic]

Beyond "Force TV" detect, like on an ATI card, I wouldn't know.  I can do S-video off my desktop's card and convert that to composite, but I didn't know you could do VGA to composite.  I do have my laptop connected to my TV in my room, but it has a built-in VGA port .  sry peaches

[Mission Difficult]

From what I can tell that model has an S-video out so try that. If the tv doesn't have an S-video input you can always get an s to composite adapter.

[cannedpeahes]

I should probably try S-to-composite if I can get my hands on one. It's just a shame I bought this adapter first.

[HeK]

You do understand that VGA is completely different from Component video, right?

VGA uses five pairs and produces 'RGB' video, while component is three-pair 'colour difference' video.

You will need either:

a) A video card that can produce component video
b) A TV that can process VGA video
c) A VGA to colour difference scan converter.


(Minor nit-picking: Component is the three RCA connectors, red, green, blue. Composite is the single yellow video cable).

[cannedpeahes]

You do understand that VGA is completely different from Component video, right?

VGA uses five pairs and produces 'RGB' video, while component is three-pair 'colour difference' video.

You will need either:

a) A video card that can produce component video
b) A TV that can process VGA video
c) A VGA to colour difference scan converter.


(Minor nit-picking: Component is the three RCA connectors, red, green, blue. Composite is the single yellow video cable).

Yeah. That's the one, composite. Sorry. Little yellow cable.

I can't see why such things as VGA-to-composite would exist if they don't... work?

[HeK]

No idea. Likely the same reason a USB 'splitter' (not hub) exists.

I know Component to VGA works on most projectors, but that's from a DVD/Xbox into a projector/TV with VGA inputs.

But doesn't work the other-way around.

[Ceceil Felias]

There'd have to be some internal logic and power for a VGA signal to be converted to a basic composite signal.

Also, regarding VGA/component comparisons, VGA D-SUB connections are still analog, whereas component is digital. A better comparison would be DVI/component, and even then you'd have to configure the device outputting the data to use an RGB set instead of a Cr/Cb/Y set. xD

If your laptop has an S-Video output, though, a converter on that would work MUCH better. S-Video in itself is just a composite cable with two seperate wires to send the analog data. xD An adapter for that is pretty simple.

[HeK]

Not to be a jerk Ceceil, but most of your post is incorrect.

http://en.wikipedia.org/wiki/Component_video
http://en.wikipedia.org/wiki/Composite_video
http://en.wikipedia.org/wiki/S-Video

[Mission Difficult]

To her credit there is a digital component video that uses the YCbCr colorsapce i believe she was referring to, but it's still way less common than analog component video.

[HeK]

To her credit there is a digital component video that uses the YCbCr colorsapce i believe she was referring to, but it's still way less common than analog component video.

In that case, I retract my previous statement.

However, doesn't the YCbCr colour space apply mainly to digital video encoding? Use of chroma sub-sampling to produce smaller files?

Whereas physical component connections are still an analog transmission, oppose to a binary signaled transmission like the common 2-bit 0,-5,+5 scheme found in digital-coaxial audio?

[Ceceil Felias]

Oh, component video is mainly analog? My bad.

Still, on the other part of my post, it's pretty clear even on Wikipedia that S-video is the same signals as Composite on seperate wires. :p

[HeK]

Pretty much. The luminance and chrominance signals are separated on S-video.

[cannedpeahes]

It's Greek to me.

What I did gather is that S-video is composite, which is good enough for me. And I think I may have understood the words luminance and chrominance.

[at0m]

However, doesn't the YCbCr colour space apply mainly to digital video encoding? Use of chroma sub-sampling to produce smaller files?

I know that Y'CbCr is highly noise-tolerant, especially on the Chroma signals. I'm not sure about it being used in digital video encoding, but I can definitely see being able to quantize those signals at a lower bitrate than you normally would use (which would allow for smaller filesize), since you can't really see the difference.

I also remember something about Y'CbCr and YPbPr being different, but I think its mainly that Y'CbCr is used to refer to a digital signal and YPbPr to an analog one encoded the same way.

<3 DSP

</random technical rant>