[mythtv-users] Re: Re: Re: Re: VGA to Component on WEGA
Cory Papenfuss
papenfuss at juneau.me.vt.edu
Fri May 20 17:58:25 UTC 2005
I have re-read my post for brain farts but haven't found any. I
did *not* say/mean that component is worse than s-vid. I said that s-vid
is worse than component, but not necessarily by much. What I was trying
to emphasize is that the tvout of most video cards (that I've used,
anyway) tends to blow chunks. The quality of the s-vid out of these cards
is often much worse than broadcast *composite*. They generally
suffer from horizontal, vertical, deinterlacing, and other temporal
scaling artifacts and loss of resolution.
If you have *good* quality s-video signal, the luminance bandwidth
can be arbitrarily good, and the chroma bandwidth can be pretty decent
(although still modulated on the color subcarrier). I don't know what the
bandwidth filtering specs are for "standard" Y/C (s-vid)... maybe there
aren't any. All YPbPr does for 480i over Y/C is not modulate the chroma
on the subcarrier. The biggest improvement is from composite to Y/C,
since the luma and chroma don't share the same spectrum and can thus be
allocated a higher bandwidth and less interference with each other.
-Cory
On Fri, 20 May 2005, Neil wrote:
>> OK. I guess I could clarify that. *GOOD* S-vid isn't that much worse than
>> component. Unfortunately, many of the cards with tvout have such sucky
>> quality that it's unusable. The homebrew hardware I built to do s-vid from
>> VGA gives results essentially the same as the component adapter... just
>> modulated as NTSC. I have long since given up on TVOUT from video cards for
>> quality reasons.
>
> Hi Cory,
> I totally disagree that component is worse than svideo. Below is the order of
> quality from good to best:
> 1. composite(1 video and LR audio channels in RCA interface)
> 2. s-video (looks like a PS2)
> 3. rgbhv
> 4. component(YPbPr in RCA interface)
> 5. dvi
> I think you really meant composite. It's true that s-vid is better than
> composite. I really can't see any difference between 3, 4 and 5. Quality of
> the 3 are awesome most especially in HDTV.
> Here is a good reference:
> http://www.michaeldvd.com.au/Articles/VideoConnectors/VideoConnectors.asp
> Thanks,
> Neil
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>
*************************************************************************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
*************************************************************************
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