[mythtv-users] New HD setup, couple questions.

Calvin Harrigan charriglists at bellsouth.net
Tue Jan 23 16:02:59 UTC 2007

So I broke down and bought an HDHR.  Neat little device.  Easily 
configured, works like a charm.  My mythtv box is a slightly older setup.

Athlon XP 1800+
512MB PC2700
400 Gig Seagate
Hauppauge PVR-250
ASRock 741GX based motherboard.
Built in Audio (no digital out :-(   )
Built in 100 MB nic
Gentoo using the latest 0.20 stable release in portage. 2156?
Sony 50" LCD projection set connected via DVI->HDMI adapter

This set has worked well for me since myth 0.7 or so.

I've been able to get this modest hardware working with HD pretty 
decently.  Using XVMC and custom modelines for my tv.  I've managed to 
create and use the following modes.

Looks awesome, no de-interlacing necessary by mythtv.
Max 65% CPU
Was able to watch a 1080i recording, record a 1080i & a SD program all 
at the same time without a much as a hiccup.

The native mode of the TV, also the mode the gui runs in.
Uses it for mythvideo (mplayer) and most myth functionality.
About 70% CPU (forgot exactly)

Works but source video needs to be deinteraced.  (one of the later 
questions).  Works well for emulators.
10-15% CPU

Works but there are deinterlacing artifacts, seems to be hardware (tv or 
video card)
10-15% CPU

Instead of trying to deinterlace,  I use the feature in myth to switch 
modes and use the deinterlacer in the tv to do the work.  I also have 
dishnetwork which I capture using the PVR250.  I switch to 480 mode to 
be able to use the wide zoom feature of the TV.  You know that mode that 
progressively stretches the image as it goes towards the edge of the TV. 
  That works great.  It results in a sharper image than scaling and 

My questions are two fold.  Because I have the 1080i modeline in the 
xorg.conf file, mythtfrontend starts up at that mode and scales fonts, 
themes etc to that resolution, though it almost immediately switches to 
1280x720p because of the mode switching options I set to run the GUI in 
1280x720p.  The fonts/graphics are really small.  (Yes I have made the 
fonts bigger in the setup screens)  Is there a way to convince mythtv to 
scale to a preset mode (1280x720p in this case) other than the mode it's 
started in?

The second question has to do with deinterlacing.  Because I couldn't 
get a good 480i mode working on my setup I have to use the 480p, thus I 
have to deinterlace the the signal I get from the pvr 250.  Problem is 
that deinterlacing seems to be a all or nothing option at this point. 
Needless to say I don't want to deinterlace the 1080i stream, just the 
480i.  Is there a way to deinterlace based on resolution, I assume it 
would have to be a hack since I couldn't find anything in the 
documentations, menu options, or the list.  I would like to add it to 
the resolution switching options if it decided which way it should be 

I'd like to thank the developers for an awesome project and the user 
community for all the interest and support in this project.

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