OpenGL video performance
dargllun at googlemail.com
Wed Apr 25 09:34:22 PDT 2012
I've posted the following inquiry to the Phoronix forum already and was
advised to post this to a more appropriate mailing list, such as this one.
Upfront, I'm sorry if you feel I should better be posting to any of the
mythtv lists. But I already did, and the fact of the matter is that 90%
of the myth people are on NV hardware anyway (can't blame them, to be
honest). So maybe this place is more appropriate.
With that being said, here's my question: is there anything one can do
to improve the real-time performance of opengl video? What would you try
or check on my system?
Background: for some time now I've repeatedly trying to get my HD3200
equipped mythtv box to use the OpenGL renderer. While things have gotten
*much* better in the course of the last 1.5 years, I still find that Xv
rendering is much more "real-time", meaning that when I use a proper
deinterlacer (hard requirement) with Xv I get smooth rendering with no
judder at all. WithOpenGL it's pretty jerky. My test case is to play
some piece of recording from a news channel with a horizontal scoll text
(like stock prices), this way you see even slight hickups. Note I'm not
even talking about h.264 output (which is, btw, also great on Xv), but
merely SD material.
I'm using Ubuntu and the fabulous oibaf drivers, and KMS. Myth is
configured to use real-time priorities. "Top" shows that there is ample
CPU time. Blanking method is DRM.
The reason for wanting opengl output is simply that in the long run the
mythtv devs plan on removing support for Xv. Also, the quality of the
onscreen menu is much better with opengl.
Any hints/tips/pointers appreciated!
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