[mythtv-users] Video offset with black bars when using JudderFree / UseVideoModes=1

[Open Media Support]

On Sat, June 10, 2017 5:02 pm, Open Media Support wrote:
>
> I've been trying to get an new frontend to frame rate switch cleanly, but
> I'm getting the video vertically displaced by 50-100+ pixels when I turn
> on UseVideoModes=1.
>

So I've done a bit more digging and it appears that UseVideoModes=1 only
works reliably with NVidia cards and VDPAU.

I've run some test with the VDPAU and Normal playback modes, with
UseVideoModes enabled and disabled. If we're running in Normal or OpenGL
modes there appears to be a call that shifts the top of the video playback
window and requires an additional call to VideoOutWindow::MoveResize

The debug output appears to indicate that in file tv_play.cpp there is a
critical section of code that is causing the change, but it doesn't occur
when using VDPAU, or perhaps the NVidia card compensates.
 - Changing from None to WatchingVideo - Line 2532
    Somewhere between these we've called VideoOutWindow::MoveResize
 - Main UI disabled - Line 2634

I'll raise a ticket and I'll upload my analysis to date under
 * https://code.mythtv.org/trac/ticket/13054





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