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

Brian Steele steele.brian at gmail.com
Wed Sep 21 19:56:09 UTC 2005


On 9/21/05, domain <domain at varga.co.uk> wrote:
>
> Brian Steele wrote:
>
> >
> >
> > On 9/21/05, *mythtv at varga.co.uk <mailto:mythtv at varga.co.uk>*
> > <mythtv at varga.co.uk <mailto: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?
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mythtv.org/pipermail/mythtv-users/attachments/20050921/754d8dc7/attachment.htm


More information about the mythtv-users mailing list