[mythtv-users] Mixing HDTV and ivtv capture cards?

[Joe Votour]

--- myth tv <myth at captainbeer.com> wrote:

> Hi All,
>  
> I've been running a frontend (viewing only) and
> backend (capture only) systems for a few months now.
>  I've very unhappy with the quality of recorded and
> live TV.
>  
> The backend is running FC4, Intel 3.2Ghz, 1GB Ram,
> 300gb SATA drive with EXT3 partition.  Its connected
> to the network through a gig-ethernet NIC into a
> Cisco switch.  The capture card is a PVR-250
>  
> The frontend is also running FC4, Intel 3.2Ghz, 1Gb
> Ram, 200gb SATA drive with EXT3 partition,
> gig-ethernet to the same switch.  The output to my
> Panasonic 42" EDTV is through an nVidia GeForece6600
> GT PCI-E card, with a monster cable DVI to HMDI
> cable.
>  
> The frontend plays DVD's with no problem, its just
> live TV and recorded TV that looks like I'm watching
> a VHS tape that's been left in the trunk of my 1978
> toyota corola in the phoenix heat for 10 years.
>  
> What I'm looking to accomplish is to:
>  
> a) have acceptable, digital cable quality viewing of
> live and recorded TV through the frontend system.
> b) use the backend for the majority of captures.  In
> the future, I may add  firewire/cable box capture to
> the frontend.
> c) use multiple capture cards in the backend.    As
> I already have a PVR-250 (ivtv), I'd like to
> continue to use it, and add in an HDTV capture card,
> (or two or three in the future).
>  
> I don't have a problem replacing some equipment, so
> if the hardware I'm using isn't fantastic for myth,
> through out some suggestions.  :)
>  
> Thoughts?
>  
>  
> Thanks!
> Ed
>  
>  
>  
> > _______________________________________________
> mythtv-users mailing list
> mythtv-users at mythtv.org
>
http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
> 

Your hardware list is fine, so I suspect that you just
need to make some changes in your configuration.

First of all, ensure that your coaxial cables for your
analog cable are pristine.  There should be a minimum
of splitters to reduce line noise/degradation.  If you
live in an apartment building (like I do), then there
may not be a whole lot that you can do there.

You don't say what hooks up into your PVR-250, but
unless it's analog cable, then coaxial is the worst
way to go.  If you're using some sort of a set-top
box, then using S-Video is probably the best that you
can use.

Secondly, change the default recording profiles - as
always, YMMV, but increasing the capture resolution
and bitrate do help to get a better picture (up to a
point, of course).

If you're not using digital cable (i.e. if you're
using analog cable), then you'll never get digital
quality out of it.  The signal is already lossy,
filled with noise by the time it arrives at your
dwelling, and then converting it to MPEG-2 will add
more artifacts (the more noise in the signal, the more
artifacts you will get).  If you want digital signal
quality, that means that you have to go digital.

I also recommend moving your filesystem where the
recordings are stored off of ext3, and onto something
like XFS.  This may not matter in a bit, since I
believe that now recordings are deleted in the
background, so the filesystem you're using isn't so
important.

-- Joe

__________________________________________________
Do You Yahoo!?
Tired of spam?  Yahoo! Mail has the best spam protection around 
http://mail.yahoo.com