[mythtv] [mythtv-commits] Ticket #3015: Internal DVD player menu text offset while using overscan

David Asher asherml at gmail.com
Thu May 31 23:45:45 UTC 2007

I have a similar problem.  Instead of using the overscan setting, I
use the gui offset and sizing options.  I also use the chromakey OSD.
this leads to 2 issues with the DVD menu buttons.

1. the chromakey osd doesn't support alpha, so the text on the buttons
is obscured.

2. because the dvd is 720x480 resolution (i'm NTSC) and my gui size is
1170x675, it is necessary to scale the size and location of the
buttons to find the right place on the OSD (which is at GUI resolution
for chromakey).  Due to roundoff errors, etc.  the button highlights
etc are never quite in the right place.  I believe the same problem
will exist with the OpenGL OSD, though I haven't tried it.

I've been thinking a lot about this and I think the correct way to fix
these type of problems is to have 2 different OSDs.  The first OSD
would be for things like the on-screen menu, program status, program
info, subtitles, etc. -- things which don't need a specific location
relative to the video image, but relative to (and sized to match) the
screen resolution.  The second OSD would be for things intended to
overlay directly on and line up with the video frame (and, as such,
sized to match the video resolution).  In this case, DVD menus.  Also
this means the "overlay" OSD would be applied to the video image
BEFORE scaling.  The "screen" OSD would not be scaled because it is
rendered @ screen resolution.

I started looking around at how the OSD is handled and this doesn't
look particularly easy to implement, especially since some setups
don't render the OSD @ screen resolution (I think chromakey OSD and
opengl OSD do, but the standard one doesn't).

It still seems like the right way to deal with the two different types
of on-screen information.

Any comments before I dive in further?


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