[mythtv] [mythtv-commits] Ticket #12311: tearing on full-screen video playback when 2D glamor accell is enabled

Michael T. Dean mtdean at thirdcontact.com
Mon Jan 12 12:18:35 UTC 2015

On 01/06/2015 04:17 PM, MythTV wrote:
> #12311: tearing on full-screen video playback when 2D glamor accell is enabled
> Comment (by warpme@…):
>   Regarding windows coordinates (second hunk) - I was trying to address it
>   with proper _playback window coordinates_ - but finally achieving this
>   becomes beyond of my MythTV code knowledge. (I'm really missing that
>   MythTV coding standard isn't forcing to comment by default...).
>   First hunk (related to window size) seems to be already within hack
>   (tv_play.cpp line1255). I don't know why in my system (X mode to TV set
>   always to 1080p50), maxHeight = display_res->GetMaxHeight(); returns 1200.
>   In all my those frontends with X modes lower than fullHD,
>   display_res->GetMaxHeight() returns expected values. I suspect issue that
>   1920x1080 display returns 1920x1200 is kind of bug....If it is bug - then
>   currently I haven't better idea to overcome it....

FWIW, if I'm parsing this correctly (you think your system has a 
resolution of 1920x1080, but display_res->GetMaxHeight() returns 1200 ), 
it sounds like the typical "user is running some variant of Xinerama and 
doesn't know it and doesn't tell MythTV."  The "variant of Xinerama" 
includes all of them (including nvidia TwinView, AMD/ATI MergedFB, 
etc.), The "doesn't know it" typically happens because your video card 
has multiple outputs (i.e. built-in LCD in laptop and HDMI output or 
even multiple HDMI/DVI outputs) and X auto-enables multiple even though 
a monitor isn't connected (or used) on one or more.  The "doesn't tell 
MythTV" part means that the Xinerama settings aren't specified, 

Display on screen
Run on the specified screen or spanning all screens.

Monitor aspect ratio
  - 16:9
  - 16:10
  - 4:3
The aspect ratio of a Xinerama display cannot be queried from the 
display, so it must be specified.

and the reason why it's important to do so is explained in the help text 
of the 2nd setting.  These settings are in the Appearance settings of 
mythfrontend, and only appear if you actually have Xinerama enabled 
(have more than one screen).  If they appear, they must be set or MythTV 
won't properly handle window-related settings.


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