[mythtv-users] Playback vid corruption with 1080i (with pics)

Glen Dragon gad at jetcom.org
Thu Jun 30 19:37:02 UTC 2005

I think that i've further narrowed down the problem. After bringing a 
different box downstairs and trying on the same display, I've learned a 
few things. -- If myth/myplayer outputs a 1080i signal at particular 
resolutions (such as 1680x1050) it will disort the output as described 

-- If other output resolutions are used it works great.  Ie 1400x1050 
works fine.

The best way that I have found to play with this is to leave X at a res 
of 1680x1050, and use the appearance options in myth to try different 
resolutions. I haven't really tried very many, since i discovered this 
late last night.

Now I wondering if the problem is with the wide screen (16:10) nature 
of the 1680x1050 resolution, or if it is just too high or something.

I'd obviously like to run at 1680x1050 since that's the native 
resolution of the LCD, and also i would want it to be wide, since 
widescreen is obviously better.

What can i do?  Does anyone know why I can't use the correct 
resolution?  Is there another resolution that would be close that might 
work?  What can I try?

Quoting Glen Dragon <gad at jetcom.org>:

> Quoting john sturgeon <john.sturgeon at gmail.com>:
>> On 6/23/05, Doug Larrick <doug at ties.org> wrote:
>>> Deinterlacing is clearly not working in these pictures.  The stripes are
>>> so wide because something (probably your video card) is scaling the
>>> pictures to a resolution less than 1080 lines high.  Double-check you
>>> have deinterlacing enabled, and check the output from 'mythfrontend
>>> --verbose playback'.  Also note that bob deinterlacing is disabled if
>>> you're playing at a speed other than 1x.
>>> -Doug
>> Doug is right on.  That is classic when resizing non-deinterlaced
>> content.  You can also see this problem if your filter chain is in the
>> wrong order, and you resize *before* deinterlacing.  You should always
>> de-interlace prior to resizing.
>> John <><
> Hmm.. I am using kernel deinterlacing.  Or at least thats what I 
> specify in the menu.  I don't have any other exotic filters or 
> anything.  I am playing at a 1x speed (normally) The display is 
> outputing onto a lcd flat panel at 1680x1050, the native resolution 
> of the display.  I have Xorg setup to do this resolution.
> I don't know how I would re-arrange the filter chain. Is this 
> configurable somewhere? I assume that X is doing the scaling from the 
> 1920x1080 to the 1680x1050. Is this correct?  If myth is doing the 
> de-int, it should be taking place before the scaling right?

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