[mythtv-users] 16:9 video playback cutting off 10% on right side

[Brian Steele]

On 9/21/05, Lee <mythtv at varga.co.uk> wrote:
>
> > >>
>
> > > >> > System specs:
> > > >> >
> > > >> > Myth 0.18
> > > >> > Nvidia FX5200, 7667 drivers
> > > >> > 2x HD-3000 capture card
> > > >> > 800x600 through TV-out over s-video.
> > > >> >
> > > >> > I had my Myth system setup and everything was working
> > > great...until
> > > >> the fan on the video card went bad and the system started
> > locking
> > > >> up.
> > > >> >
> > > >> > I was using a Nvidia 6200 AGP video card but I replaced
> > it with a
> > > >> fanless FX5200 card. After I replaced the video card and
> > rebooted,
> > > >> the Myth interface looked exactly the same as before,
> > filling the
> > > >> screen with very little overscan. I then attempted to
> > playback some
> > > >> recorded TV and discovered that on 16:9 material, at least
> > > 10-15% of
> > > >> the picture is missing on the right side. 4:3 material
> > seems to
> > > work
> > > >> fine.
> > > >> >
> > > >> > This did not happen with the 6200 card. I didn't change any
> > > settings
> > > >> in .nvidia-settings-rc or in XF86Config-4, so I don't
> > know what's
> > > >> causing this. Does anybody have any ideas?
> > > >>
> > > >> Different video cards sit the screen in slightly
> > different places,
> > > >> it's just a fact of life. You'll need to tinker with the
> > > modeline in
> > > >> the XF86Config-4 file, just take it slowly.
> > >
> > > > I don't think that's the problem. The X desktop and the
> > Myth UI both
> > > > look correct. Neither of them is getting 10-15% of the
> > picture
> > > chopped
> > > > off on the right side. I only see the problem during 16:9
> > video
> > > > playback. I have Myth configured to use the same video
> > mode for
> > > the GUI
> > > > and for playback, so it isn't that either.
> > >
> > > Are you definitely running your desktop in the same 16:9 mode?
> > > Do you have any other modelines defined?
> > >
> > >
> > > I really appreciate the help.
> > >
> > > My desktop is definitely running at 800x600. This is a 4:3 mode.
> > > There are other modelines defined, but as I said before I didn't
> > > change anything in XF86Config-4 when I switched video cards. I'll
> > > delete everything besides 800x600 to see if it makes a difference.
> > > The Myth UI is running full screen.
> > >
> > > Let me try to clarify the problem.
> > >
> > > Desktop resolution is 4:3, displaying on my TV via s-video.
> > > I'm recording OTA HD.
> > >
> > > 4:3 shows that were broadcast with 16:9 aspect ratio display
> > with grey
> > > bars on the sides. Changing Myth to 16:9 Zoom aspect ratio makes it
> > > use the full screen. This is the behavior I expect.
> > >
> > > 16:9 shows that used to take the full width of the screen with
> > black
> > > bars at the top and bottom now have 10-15% of the picture pushed off
> > > the right hand side of the screen. Regardless of what aspect
> > ratio I
> > > tell Myth to use for display, some of the picture is always lost.
> > > 16:9 stretch seems to be the closest to keeping all the
> > picture. With
> > > my old video card, I could leave the myth aspect ratio set to
> > > "default" and I wouldn't lose any picture.
> > >
> > That's exactly my point, 16:9 goes off the screen, it doesn't
> > matter if
> > it's the desktop or Xine.
> > All s-video out graphics cards generate an analogue signal, just
> > because
> > you're using the same modeline with the new card as with the old one
> > doesn't necessarily mean that the picture will appear in the same
> > place
> > on the tv/monitor. The modeline controls the pixels x-y, the physical
> > width-height and the x-y positioning on the screen, but it's all
> > relative due to inconstancies in the hardware.
> >
> > Remove all the modelines apart from the ones you need, find a good
> > modeline explanation on Google and start tinkering.
> > Adjust them a little at a time and with a bit of work, you'll be
> > able to
> > tweak it so it's perfect.
> >
> >
> >
> > I understand what you are saying, but could you please explain to me
> > how or why Myth is switching to a different modeline during video
> > playback? It shouldn't be doing that should it? The modeline I'm
> > running is 4:3, and the picture doesn't go off the screen when viewing
> > the X desktop or the Myth UI. Why would it suddenly switch to a
> > different modeline for video playback? Shouldn't it just scale the
> > 16:9 video to fit the 4:3 modeline?
>
> Is it the Myth video player or Xine? As I understand it, if you try and
> view 16:9 content it will change resolution, rather than rescale the
> video.
> Your modelines say that's OK, so that's what it's doing... If you don't
> want it to do that, then remove the modelines (except the 800x600) and
> it won't be able to...
>
>
>
This was happening when watching shows I had recorded using Myth and playing
back using Myth.
I switched from 800x600 to 640x480 and that fixed the problem. I have no
idea why though.
Anyway, thanks to everybody for the help.
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