[mythtv-users] auto frame rate change

Jason Kitching jason at jadrallypix.me.uk
Sun Nov 22 14:10:29 UTC 2015


The driver will just add your custom modelines to the total pool of
available modes unless you tell it to ignore the others..

Unless this "VertRefresh     56.0 - 62.0" is being ignored because it
does not compute with the custom modelines then you're getting 60Hz
output only.
You can read thru' /var/log/Xorg.0.log file to find out..

If you remove the 24p modeline & have 60p (59.xx) mode the default then
video card will convert 24->60p with pull-down. Change the metamode in
device section to be 60Hz.
Sadly VDPAU does not (yet) have a 24p frame rate doubler..

Remove (comment out) the interlaced modelines because the video card
should be better than the TV.

The remaining 2 modelines are not right, they are just made up for some
old projector (VGA possibly).
The ~60Hz one should be using reduced vertical blank timing:
Modeline "1920x1080R"  138.50  1920 1968 2000 2080  1080 1083 1088 1111
+hsync -vsync
  and the 50Hz one:
Modeline "1920x1080_50.00"  141.50  1920 2032 2232 2544  1080 1083 1088
1114 -hsync +vsync

Blm

---------------------

Followed that Blm, thanks, can see the default change to 60Hz but 24fps
still being forced so I checked /var/log/Xorg.0.log and found that
nvidia-auto-select kicks in and sets the res to 1920_1080_24.

Strange though as the auto select line isn't present in the xorg.conf
file. Quick search about disabling auto-select lead me to the ubuntu
forum where another user had a similar problem with auto-select kicking
in and the xorg.conf file was being ignored. Instead one of the conf
files in /usr/share/X11/xorg.conf.d was being used.

I will have a look later in that directory and see if I can figure out
what exactly is causing nvidia-auto-select to run.

Thanks.

Jason

A very good source of info is the driver readme:
http://us.download.nvidia.com/XFree86/Linux-x86/352.55/README/xconfigoptions.html

Unless you exclude internal video modes & those calculated from display
EDID.. you end up with a pool of modes.

The video driver does the right thing. It chooses the best mode from the
pool or one you select.

Some mix of these options (in xorg.conf) should prevent the auto-select
mode:

Option "ModeValidation" "DFP-1: AllowNonEdidModes, NoXServerModes,
NoVesaModes, NoEdidModes, NoPredefinedModes"

The (2) modelines I suggested are very likely the same as internal modes
(because they are standardized).



Thnks for the help and the link, most helpful. This reply is simply a note to say thanks for your efforts and for info.

I can now disable 24fps with the Option line of either
Option "UseEdidFreqs" "boolean"
     Option "UseEDID" "FALSE"
     Option "UseEDIDFreqs" "FALSE"

The screen sets to 60hz but 50hz now no longer works. The /var/log/Xorg.0.log shows no valid modes for 1920x1080_50+0+0 ignoring. If I then disable the option lines the 1920x1080_50 line validates as does the 1920x1080_60 line. Guess there must be a hardware glitch somewhere that prevents it reporting correctly. I've now spent the best part of a week trying to figure it out and tbh it's now not worth the effort. Far simpler just changing from Auto to 60hz in mythtv for when I play 24fps media.




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