[mythtv-users] VGA to Component adaptors

[Tom Lichti]

Cory Papenfuss wrote:
>> There is a thread on nvnews about the component out in Linux, but no 
>> real conclusions yay or nay. Someone here (Cory?) built his own, but I 
>> never did get all the details. Seemed pretty simple from what I remember.
>>
>     Ooops... I just re-read what I was accused of accomplishing.  The 
> circuit I built converterted RGBHV (i.e. VGA) at 480i frequencies to 
> *composite* (and s-vid).  It wasn't component.
> 
>     The RGBHV->component is a much easier circuit, though.  There are 
> lots of instructions on the 'net for how to build a transcoder for that. 
> The toughest part is figuring out which gain matrix is correct for 
> RGB->YPbPr... there seem to be a few different ones floating about.
> 
>     Also, one minor caveat that I think most people happily ignore is 
> that component video is supposed to have bipolar sync signals. Unlike 
> the TTL-like signals of RGBHV, component sync is supposed to be 
> nominally zero, go negative for a bit, then posititive for a bit, then 
> back to zero.  It keeps the DC level of the sync signal zero so DC 
> restoring circuits aren't necessary.
> 
>     I don't recall any of the DIY transcoders doing that, but they seem 
> to work all the same.
> 
> -Cory

The more I research this, the more I think I'll just buy a premade one...

Tom