[mythtv-users] OT - aspect ratio and non-square pixel display

[HP-mini]

The latest nVidia driver series has returned the over/underscan GUI
tool.
For the previous you had to use viewportin/out..

To override the DPI from EDID (if any):
/etc/X11/xorg.conf
Section "Monitor"
   Identifier   "Monitor1"
   <snip>
   UseModes      "myHDTV"
   DisplaySize   650   366
EndSection

Section  "Screen"
   <snip>
   Monitor   "Monitor1"
   Option    "UseEDIDDpi"  "False"
   Option    "ConstantDPI"   "False"
EndSection

EOF

FWIU If the Option "DPI"  "string" is used. it ignores the displaysize.

The display size is normally calculated from DPI & native pixel size.
xdpyinfo | grep -B1 dot

You could post a link to copy of /var/log/Xorg.0.log file..