[mythtvnz] Video Motion Blur

Tue, 19 Sep 2006 15:02:33 +1200

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my suggestion is that it is part of the default mpeg4 compression settings,
open divx is not a great codec I suggest myth switch to xvid, particularly
the max and min quality settings and how much it is allowed to change
between frames ;-)

On 19/09/06, Duncan Kennington <bubba@paradise.net.nz> wrote:
>
> Quoting Steven Ellis <steven@openmedia.co.nz>:
>
> > David Zanetti wrote:
> > > Fairly common problem, most TV encoders are trying to do progressive
> > to
> > > interlaced conversions and not neccecarily doing a great job of it.
> > The
> > > video doesn't always line up with the scan lines, and conversion
> > between
> > > the two is ugly, so the whole thing gets a bit soft.
> > >
> > > And the original content was interlaced, so you've really got
> > > interlaced->progressive->interlaced in there.
> > >
> > > One of the drivers I have for getting a decent HD set is not really
> > all
> > > that HD content out there, but so I can drive it over HDMI in a
> > > progressive mode and bypass a few conversion steps.
> >
> > Tried a number of HD screens over DVI->HDMI and the blur is still high.
> > Got a de-interlacer enabled to perform
> >
> >  interlaced->progressive
> >
> > Still isn't as clear as a DVD player.
>
> I find this with the the (non-HD) plasma I have.  It is a
> progressive/interlace
> problem as David says.  If you drive your display with an interlaced
> signal
> (TV-out off the video card) then the card will be interlacing a
> progressive
> signal which is probably showing a deinterlaced version of an interlaced
> recording.
>
> To eliminate some of this conversion, driving the display digitally is
> obviously
> a better option, hence using DVI or HDMI.  You can even use VGA or
> component out
> (if you have one of those $400+ NVidia cards) to drive the display
> progressively.  This will make your menus and non-recorded stuff look
> better
> (should do, anyway!)
>
> If you play a progressive-scan DVD or AVI file across this progressive
> picture
> you should see pretty good rendering of it.  But you won't see DVD quality
> rendering - I agree.  I think this can be for one or two reasons: one:
> you're
> trying to display 25 (or maybe even 30) frames a second on a display
> that's used
> to showing 50 or 60 fields.  24-25 frames is about as slow as you can go
> before
> you start to see the frames individually.  I think this is where you start
> to
> see the frames chopping a bit (the top half of the picture not keeping up
> with
> the bottom) when there is a lot of motion in the picture (like a sports
> game
> with lots of panning).  Two could be to do with the speed at which the
> signal is
> delivered to the display (though DVI must surely be able to keep up) and
> or the
> quality of the source recording (remembering that it was recorded
> interlaced but
> this will never come out properly on a media centre style setup unless you
> use
> something like the PVR-350's TV out.
>
> Progressive scan DVDs do some up-conversion anyway, I think, doubling
> frames up
> for a faster frame rate?
>
> Personally I'm going to try a better graphics card, as rendering of
> downloaded
> HD content (like the WMV samples) is *almost* spot on.  And only over
> VGA...
>
> Once that's fixed then I'll start tweaking the capture settings. :)
>
>
>
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-- 
Craig Appleton
http://mythblasterz.gotdns.com/
Email: c.g.appleton@gmail.com
Phone: +64 27 472 9531
MSN Messenger: c_g_appleton@hotmail.com

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my suggestion is that it is part of the default mpeg4 compression settings, open divx is not a great codec I suggest myth switch to xvid, particularly the max and min quality settings and how much it is allowed to change between frames ;-)
 <div>On 19/09/06, Duncan Kennington &lt;<a href="mailto:bubba@paradise.net.nz">bubba@paradise.net.nz</a>&gt; wrote:<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Quoting Steven Ellis &lt;<a href="mailto:steven@openmedia.co.nz">steven@openmedia.co.nz</a>&gt;: &gt; David Zanetti wrote: &gt; &gt; Fairly common problem, most TV encoders are trying to do progressive &gt; to
 &gt; &gt; interlaced conversions and not neccecarily doing a great job of it. &gt; The &gt; &gt; video doesn't always line up with the scan lines, and conversion &gt; between &gt; &gt; the two is ugly, so the whole thing gets a bit soft.
 &gt; &gt; &gt; &gt; And the original content was interlaced, so you've really got &gt; &gt; interlaced-&gt;progressive-&gt;interlaced in there. &gt; &gt; &gt; &gt; One of the drivers I have for getting a decent HD set is not really
 &gt; all &gt; &gt; that HD content out there, but so I can drive it over HDMI in a &gt; &gt; progressive mode and bypass a few conversion steps. &gt; &gt; Tried a number of HD screens over DVI-&gt;HDMI and the blur is still high.
 &gt; Got a de-interlacer enabled to perform &gt; &gt;&nbsp;&nbsp;interlaced-&gt;progressive &gt; &gt; Still isn't as clear as a DVD player. I find this with the the (non-HD) plasma I have.&nbsp;&nbsp;It is a progressive/interlace
 problem as David says.&nbsp;&nbsp;If you drive your display with an interlaced signal (TV-out off the video card) then the card will be interlacing a progressive signal which is probably showing a deinterlaced version of an interlaced recording.
 To eliminate some of this conversion, driving the display digitally is obviously a better option, hence using DVI or HDMI.&nbsp;&nbsp;You can even use VGA or component out (if you have one of those $400+ NVidia cards) to drive the display
 progressively.&nbsp;&nbsp;This will make your menus and non-recorded stuff look better (should do, anyway!) If you play a progressive-scan DVD or AVI file across this progressive picture you should see pretty good rendering of it.&nbsp;&nbsp;But you won't see DVD quality
 rendering - I agree.&nbsp;&nbsp;I think this can be for one or two reasons: one: you're trying to display 25 (or maybe even 30) frames a second on a display that's used to showing 50 or 60 fields.&nbsp;&nbsp;24-25 frames is about as slow as you can go before
 you start to see the frames individually.&nbsp;&nbsp;I think this is where you start to see the frames chopping a bit (the top half of the picture not keeping up with the bottom) when there is a lot of motion in the picture (like a sports game
 with lots of panning).&nbsp;&nbsp;Two could be to do with the speed at which the signal is delivered to the display (though DVI must surely be able to keep up) and or the quality of the source recording (remembering that it was recorded interlaced but
 this will never come out properly on a media centre style setup unless you use something like the PVR-350's TV out. Progressive scan DVDs do some up-conversion anyway, I think, doubling frames up for a faster frame rate?
 Personally I'm going to try a better graphics card, as rendering of downloaded HD content (like the WMV samples) is *almost* spot on.&nbsp;&nbsp;And only over VGA... Once that's fixed then I'll start tweaking the capture settings. :)
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 -- Craig Appleton <a href="http://mythblasterz.gotdns.com/">http://mythblasterz.gotdns.com/</a> Email: <a href="mailto:c.g.appleton@gmail.com">c.g.appleton@gmail.com</a> Phone: +64 27 472 9531 MSN Messenger: 
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