[mythtv-users] VGA to component cables

Stroller linux.luser at myrealbox.com
Sun Jan 7 15:52:26 UTC 2007


On 5 Jan 2007, at 14:02, Cory Papenfuss wrote:

>> [1] <http://www.lenexpo-electronics.com/2M-6FT-ATLONA-HIGH-QUALITY-
>> VGA-TO-COMPONENT-VIDEO-BREAKOUT-CABLE-p-16189.html>
>>
>> I think other posters have also conjectured that such a cheap cable
>> surely has no electronics in it to convert from RGB to YPbPr, and is
>> surely:
>> 1) Mis-labelled on the website.
>> 2) Actually outputting RGB.
>>
>  	This is the actual case:
>    No electronics, simply breakout cable for the Red/Green/Blue output
> D/A's and video amps on the video card to connect to RCA  
> connectors.  The
> video card and *driver* for the card then simply outputs color- 
> transformed
> data (Y, Pb, Pr) out the R, G, B channels... plus adds a "sync-on-Y"
>
>  	The card and driver must support this functionality.  I do not
> know if anything other than ATI does or whether or not linux drivers
> support it.

Hi there,

I'm confused by this. VGA _by definition_ carries RGB signals, no?

I think you're saying that some ATi cards can, with the right  
drivers, output  YPbPr through their VGA-output connector. Is this  
correct?

If my understanding is correct, then the cable above would be better  
referred to as a "15-pin D-sub to component video breakout cable"; as  
you surmise it will not breakout YPbPr from a _standard vga_ (or SVGA  
or XGA &c) output.

The fact that we're having this discussion, and the OP's questions  
about its suitability, suggest that the website's labelling of this  
cable is misleading - one would reasonably expect to plug a "VGA-to- 
component video breakout cable" into a VGA port at one end and a  
telly's component inputs and have at least the right colours come out.

Stroller.



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