[mythtv-users] Interlacing question

Louie Ilievski loudawg at comcast.net
Sat Oct 21 02:38:01 UTC 2006


On Monday 16 October 2006 07:59, Sage wrote:
> Thanks for the tips!  My next question is, how do I set xorg up to do this?

I don't know if things have changed since the last time I've tried this, but 
from my experience what you're trying to achieve is pretty much impossible.  
If I added up all the hours I've spent trying to achieve this same goal, I 
would say I've spent at least a full week on it (as in 24 hours each day for 
a week).  I've tried everything imaginable and have read everything on the 
net related to this.  There are also several posts on the myth lists from the 
past where people have pretty much said because of the processing that 
happens on the nvidia tv-out chip, it's really not possible to achieve a 
proper, true interlaced output.  And from all my experience and 
experimentation, I can pretty much verify this is the case.  I tried to avoid 
any scaling by both mythtv and the tv-out, tried a million modelines, tried 
playing with every combination of every setting in nvidia-settings, recorded 
at the proper resolution, etc, and nothing has worked at all.

Now, although I have since moved on to a new HD LCD display and this doesn't 
really apply to me anymore, I would be VERY interested if you are able to 
accomplish this, since I still occasionally set myth systems up for friends 
and family, and even wouldn't mind having another frontend for my CRT in 
another room or something.  I will literally bow down to anyone who makes 
this happen and buy them a case of their favorite brew.  :-)

Good luck and may the force be with you,

~Lou

P.S.  On  a side note, were you able to get X to run at 720x480 and fill the 
entire screen?  If I remember right I had black bars on the sides.  Err 
actually come to think about it, it was actually playback in MythTV that had 
the pillarbox output.  I think I had to stretch or zoom or something to make 
it fill all the way.  I can't quite remember since it has been quite a while.

>
> On 10/16/06, Daniel Kristjansson <danielk at cuymedia.net> wrote:
> > On Sun, 2006-10-15 at 23:27 -0500, Sage wrote:
> > > I'm currently running MythTV through an nVidia Geforce 6150 with an
> > > s-video connection to a standard NTSC television.  The resolution of
> > > X-windows is 720x480.  I'm using a Hauppauge WinTV PVR-150 to record a
> > > regular NTSC stream.  What this means is that all my recordings are
> > > 720x480 interlaced video.
> > >
> > > The thing is, x-windows is set to a non-interlaced (480p) resolution.
> > > Which means that the video must be de-interlaced during playback.
> > > However, since my display is a regular NTSC television, the end result
> > > is interlaced again.
> > >
> > > So I'm wondering: Can you set x-windows to actually operate entirely
> > > in 480i, so that you don't have to de-interlace the video stream at
> > > all?  Would this work?
> >
> > Yes, and yes, however if you do this and use MythTV "overscan" or "zoom"
> > modes you will still need deinterlacing and you will need to record all
> > streams with 480 lines, i.e. 720x480 is ok, as is 640x480, and 480x480.
> >
> > -- Daniel
> >
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