[mythtv-users] stuttering video in LiveTV with greedy2x and yadif2x

[Tino Keitel]

On Wed, Jul 02, 2008 at 12:47:51 -0700, Brad DerManouelian wrote:
> On Jul 2, 2008, at 12:36 PM, Tino Keitel wrote:
> 
> > Minor correction: bob2x has the same problem.
> >
> >>
> >> When this happens, hit pause and then resume playing to see if it
> >> clears it up. It sounds like it's trying to read more video than is
> >> currently in the buffer. Since these deinterlacers read ahead of the
> >> current frame, it makes even more sense that is what is happening.
> >
> > I doesn't help.
> 
> Are you *sure* it doesn't happen when watching recordings and ONLY  
> when watching LiveTV?

At least I never saw this with recordings.

> The reason I ask is because there is no difference between the two  
> except the fact that a recording is a completed file and LiveTV is  
> reading the last bit of the file that has just ben saved.
> 
> I find it more likely that these deinterlacers are not working because  
> your resolution is not capable of a 2x framerate. Someone else will  
> have to chime in with the specs required to use a 2x framerate  
> deinterlacer. I don't know them off the top of my head.

It seems to be caused by a strange Xorg behaviour (or bug?). I set the
refresh rate to 60 Hz using xrandr --rate 60. However, if I check
xvidtune, it still shows 50 Hz. After running xrandr --rate 60 again,
xvidtune shows 60 Hz.

And after running xrandr --rate 60 a second time, the stuttering video
doesn't seem to occur anymore.

I tried again and was able to reproduce that. Here is what I did:

$ xrandr --rate 50
$ xrandr --rate 50

$ xvidtune -show
"1024x768"     54.16   1024 1048 1184 1344    768  771  777  806 -hsync -vsync

$ mythfrontend -> stutter happens

$ xrandr --rate 60

$ xvidtune -show
"1024x768"     54.16   1024 1048 1184 1344    768  771  777  806 -hsync -vsync

$ mythfrontend -> stutter happens

$ xrandr --rate 60

$ xvidtune -show
"1024x768"     65.00   1024 1048 1184 1344    768  771  777  806 -hsync -vsync

$ mythfrontend -> no stutter happens

Regards,
Tino