[mythtv-users] More Beginner Questions

Stroller linux.luser at myrealbox.com
Sun Jan 21 22:09:07 UTC 2007

On 21 Jan 2007, at 20:17, Greg Kettmann wrote:

> Well, I've spent many hours reading and there are still times when I
> think I get more confused instead of less...
> In a previous post I indicated I'm interested in HDTV ...  the  
> comments,
> plus further reading, indicate that this probably isn't a great  
> starting
> point.  One of the major reasons for that would be the lack of an  
> HDTV /
> Analog card.  Since I need to buy an analog card anyway I should
> probably start there and then build up.  I just want to keep in mind
> where I'd like to end up and not buy components which are not  
> sufficient
> for the final vision.  So, for example, I'll start with a system with
> enough horsepower to output/decode an HD stream.

Don't make a big deal out of this or worry too much - it shouldn't be  
at all a problem to buy an analogue card now and slap in a DVB card  
in a few weeks time. If no HDTV / Analog cards (I assume you mean  
combined?) are available then I'd personally be inclined just to buy  
two cards at the first instance - I don't know about DVB-C cards but  
the DVB-T & DVB-S cards we use here in the UK are only about 40 each.

> ...  It's a little disconcerting
> the direction of the cable companies, etc.


>  ... All I want to do is time
> shift my favorite shows, like we've done for years since the advent of
> the VCR.  Oh well.

I think - to be fair to the cable companies - that they have been  
consistent, and opposed the VCR back in the day, too. The geek  
community heralded Zimmerman's PGP as "cheap encryption for all" -  
unfortunately it is the modern cheapness of encryption that now  
allows the cable companies to achieve what they've always wanted.

> 2)  TV-out - Keep in mind that I'd eventually like HD.  My TV is  
> capable
> of this.  The Hauppauge PVR-350 does composite out but I suspect it's
> the standard RGB and I think HD requires YPbPr.

Composite out is nether RGB nor YPbPr - it is a "composite" signal of  
all the colours down one wire. This is the yellow phone cable you  
often see on TV-output cables - maybe the one for your iPod or  
digital camera; the white & red phono plugs that accompany the yellow  
plug just carry sound. Composite is not well regarded for image quality.

In RGB the colours are completely separated (well, 3 wires down one  
cable) and in component (YBbPr?) the colour "components" are (pretty  
much) also separated but in a different way (I think luminance is  
mixed in there somewhere?).

> Is this correct?

You are correct in thinking that component (YPbPr) is the best of  
these signal types.

I believe that S-Video is also a consideration, and that it, too, can  
carry a decent signal. However I don't know much about this. I  
believe that many TV-outs accommodate it, and I believe that some S- 
video cables may carry composite.

> I believe my TV will take either.  If the PVR-350 won't work then  
> it looks
> like an NVidia card should be considered, however, although they list
> "composite" output I don't find any definitions of the RBG / YPbPr
> aspect.  Do I have something wrong?  The only writeup I've seen on HD
> output used a device (for a bit over $100) that converted a  
> standard VGA
> type monitor jack into a composite/YPbPr signal.  I'd prefer something
> on a card.

Do you have something wrong? Only the common mistake of confusing  
composite & component. I think everyone must do this at first!!

Component output on video cards is not well advertised, but it is  
available. Quite a few nVidia based cards offer it - I think nVidia  
stuck it on one of their reference cards and all their OEMs have just  
copied that; they all seem to use a similar convertor "dongle".  
Search gossamer for "nvidia component" and you'll see my posts of 2 -  
4 weeks ago; the keyword on the packaging at PC World is, I think,  
"HDTV out" or "Hi-Def out", one of the two.

I have read of people using VGA to component convertor boxes but like  
you, I don't think it's necessary. Audio Authority are a brand-name  
to search for if you want to know more. VGA to composite convertor  
boxes are readily available (and cheap) but again give shitty image  

> The obvious issue is how to I connect the MythTV box to the
> television at the desired resolutions and it's still unclear how to do
> this.

I didn't find this terribly well documented - connecting with RGB or  
component, I mean. Someone posted this weekend about using a homemade  
VGA -> RGB cable, for instance, but you find so many disclaimers on  
the net that this will (probably) only work with brand-X video cards  
(I don't think one of these has ever been proven to have actually  
fried a TV) that I couldn't be arsed.

My investigations indicated that there are quite a number of people  
happily connecting Myth to their TVs using good quality analogue  
connections - certainly, I found no evidence that anyone had failed  
to do so, but I'm actually chickening out of this route, myself. Pure  
laziness, really, mixed with aspirational geek consumerism - I plan  
to just get a TV with digital inputs which I'll connect to using DVI,  
but this is an expensive route & I think a good recommendation would  
be one of the nVidia cards with component.


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