[ATrpms-users] More on VIA XvMC and MythTV 0.21

[John Robinson]

Hi folks, I've recently updated to mythtv-0.21-184 and am having some 
problems with XvMC on my VIA EPIA M-II 10k, with CLE266 Unichrome 
chipset, using CentOS 5 plus Xavier's openchrome driver build from EPEL.

If I try to use XvMC playback, mythfrontend crashes out with a segfault, 
having reported that the xvmc-blit renderer doesn't exist; it appears 
it's falling back to OpenGL, and a bit of Googling suggested the 
segfault happens because Mesa 6.5.1 is bad on *chrome chips. In any case 
OpenGL is the wrong thing to fall back to, in my opinion.

Restarting mythfrontend with LIBGL_ALWAYS_INDIRECT=Y makes it work, but 
now the bob deinterlace keeps going in and out of sync; I think it only 
worked before (in 0.20) because it depended on getting the output sync 
pulse via OpenGL... Then I remembered the "OpenGL vertical sync for 
timing" option and ticked it, which helped a little but doesn't make it 
perfect. I suspect taking the video sync from OpenGL only really works 
properly when GL isn't indirect?

Anyway, there's a bug and patch in myth SVN which would make the 
fallback from xvmc-blit go to xv-blit before opengl:
http://svn.mythtv.org/trac/ticket/4792 and 
http://svn.mythtv.org/trac/attachment/ticket/4792/mythtv-0.21-ticket-4792.patch 

which I think would help me and others who want XvMC but not OpenGL.

Or have I got it all wrong and am in fact doing something stupid? It 
wouldn't be the first time :-)

Cheers,

John.