[mythtv-users] blurriness when playing 1080i -> 1080i

Seth Daniel mythtv.org at sethdaniel.org
Mon Mar 19 23:56:09 UTC 2007

On Mon, Mar 19, 2007 at 07:29:11PM -0400, Steven Adeff wrote:
> On 3/19/07, Seth Daniel <mythtv.org at sethdaniel.org> wrote:
> > On Mon, Mar 19, 2007 at 07:07:33PM -0400, Steven Adeff wrote:
> > > On 3/19/07, Seth Daniel <mythtv.org at sethdaniel.org> wrote:
> > > > On Mon, Mar 19, 2007 at 10:00:33AM -0400, Steven Adeff wrote:
> > > > > > The blurriness only happens around action.  Anything that is static
> > > > > > won't be blurry.  Imagine a field with a giant logo in the middle and
> > > > > > people running around on it.  If the camera is locked then the people
> > > > > > will be blurry but the logo will look fine.  If the camera pans then
> > > > > > the logo may look blurry along with the people running around.
> > > > >
> > > > > not really a solution, but that CPU should be able to more than handle
> > > > > deinterlacing 1080i with Bob.
> > > >
> > > > Yes, it can.  Any deint method causes non-smooth playback when I am
> > > > playing 1080i content @ 1080i.  It's not a CPU issue since neither core
> > > > is working all that hard.
> > >
> > > do you have "use video as timebase" enabled?
> >
> > I'm confident I've tried that option.  At one point I created a matrix
> > of options for Nvidia and Myth that seemed likely to affect the
> > playback.  I went through each row in the matrix and nothing seemed to
> > change (wrt this problem).  When I get back from work I'll try it again.
> > I presume you want me to try this option while deinterlacing.  You
> > aren't suggesting that this could solve the blurriness problem are you?
> it should be off. what exactly does "not smooth" entail? Whats the
> 1080i modeline your using?

"not smooth" means it looks like 1 of every 3 or 4 frames is getting
dropped.  This is particularly noticeable during panning or any scene
with a lot of action.  You can also tell during less action-oriented
scenes, but it is less obvious.

The modeline is: 

Mode "1080i"
  DotClock   74.25
  HTimings   1920 2008 2052 2200
  # VTimings    540  542  547  562
  VTimings   1080 1084 1094 1124
  Flags      "Interlace" "+HSync" "+VSync"

The commented out VTimings is what is in the EDID returned by my TV.  The newer
(i.e. 9xxx) nvidia drivers treat this as a literal 1920x540 *interlaced*
screen.  In other words my vertical resolution is actually chopped in half.
More information on this and the workaround I am using (doubling the vtimings)
are here: http://www.nvnews.net/vbulletin/showthread.php?t=69255 
At one point I tried to get the driver to do 1920x540p, but I could never get
that to work.  

The later 8xxx drivers did the right thing and would display a 1920x1080
interlaced screen w/o the need for a custom modeline, but there were problems
with xv playback (the machine would lock or I'd get a black screen and mythtv
or mplayer would lock).  

I have also asked about this blurriness problem on the nvnews.net linux forum.  Not much from Nvidia, but one response suggests I need to go back to the 8183
driver.  http://www.nvnews.net/vbulletin/showthread.php?t=88365

I find it interesting that all of these problems, blurriness or non-smooth playback, only occur with 1080i content.  720p content looks absolutely wonderful at 1080i (as does 480p and 480i).  No blurriness, smooth as can be, etc...

seth / @sethdaniel.org
I either want less decadence or more chance to participate in it.

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