[mythtv-users] Choppy video and sound

[John P Poet]

On 1/3/06, matthew.garman at gmail.com <matthew.garman at gmail.com> wrote:
> On Tue, Jan 03, 2006 at 09:13:10PM -0700, John P Poet wrote:
> > OpenGL does not work for everyone.  If it does work for you, then
> > you definately want it.  OpenGL provides the smoothest video
> > refresh synchronization.
>
> Does it not work for everyone due to hardware, or that it "just
> won't work" for some folks?  :)


Some people claim that enabling OpenGL causes their machine to lock
up.  I seem to remember Daniel Kristjansson committing some fixes to
svn which *might* help with that.  I have never personally had that
problem, so don't know.


> > On your frontend, in Setup->TV Setting->Playback, the very first
> > screen should have an option to enable OpenGL.
>
> Hmmm, I can't seem to find the OpenGL playback option.  Just for a
> sanity check, here's the version of myth I have installed with the
> various USE flags (this is gentoo obviously):
>
>     media-tv/mythtv-0.18.1-r1  +alsa (-altivec) +arts -debug +dvb
>     -frontendonly -jack -joystick -lcd +lirc +mmx +nvidia +opengl
>     -oss -unichrome +vorbis


Been so long since I ran .18 that I don't remember if there was a
checkbox back then.  I see that you have opengl in your build configs,
so that might be good enough -- Based on your logs below, it is.


> > Also, make sure you are running nVidia driver 7676 or *earlier*.
> > Drivers after 7676 do not work correctly with OpenGL vsync.
>
> Okay, I downgraded my nvidia-glx and nvidia-kernel versions:
>
>     media-video/nvidia-kernel-1.0.6629-r4
>     media-video/nvidia-glx-1.0.6629-r6


I have always installed nVidia drivers direct from nVidia's scripts:

http://www.nvidia.com/object/unix.html

I assume those two packages are equivalent.


> I was using 8178, against many warnings I've seen on this mailing
> list.  My bad, I had a case of "this problem won't affect me"!  At
> any rate, that alone seemed to help the playback somewhat.
>
> Regarding all the warnings I've seen about using the newer nvidia
> drivers with mythtv, does anyone happen to know *why* such things
> are broken with the newer drivers?  Is nvidia aware of these
> problems?  Any feedback from them regarding fixes, etc?


I don't know.  Since version 7676 works pretty well for me, I did not
follow up on the problem.


> > mythfrontend -v playback -l /var/tmp/mythfrontend.log
> > ...
> > If the "Video Timing method" is not OpenGL, then you need to look
> > at the preceding statements to figure out why.
>
> Okay, I'm definately not using OpenGL for video playback:
>
>
> 2006-01-03 23:03:53.344 nVidiaVideoSync: VBlank ioctl did not work, unimplemented in this driver?
> 2006-01-03 23:03:53.344 DRMVideoSync: Could not open device /dev/dri/card0, No such file or directory
> 2006-01-03 23:03:53.346 OpenGLVideoSync: GLX extensions: GLX_ARB_get_proc_address GLX_ARB_multisample GLX_EXT_import_context GLX_EXT_visual_info GLX_EXT_visual_rating GLX_OML_swap_method GLX_SGI_make_current_read GLX_SGIS_multisample GLX_SGIX_fbconfig
> 2006-01-03 23:03:53.346 OpenGLVideoSync: GLX Video Sync extension not present.
> 2006-01-03 23:03:53.346 RTCVideoSync: Could not set RTC frequency, Inappropriate ioctl for device.
> 2006-01-03 23:03:53.347 Using audio as timebase
> 2006-01-03 23:03:53.347 Video timing method: USleep with busy wait


Ouch!  If I understand things correctly, "USleep with busy wait" is
the *Worst* option.  If you cannot get OpenGL working, at least try to
get RTC working -- it is almost as good as OpenGL.


> I see that it says "GLX Video Sync extension not present"---does
> this mean I've failed to configure something or does my hardware not
> support it?  I was under the assumption that my hardware *did*
> support hardware OpenGL.  I've got a Chaintech 7NIF2, which has the
> integrated nvidia nv17-class gpu (GeForce4 MX).


I am guessing that the GLX module did not get installed.  Or, it is
the wrong version.

I have had problems in the past where an install of the nVidia drivers
failed because it was not able to successfully remove the previous
version.  Once I hand-removed the previous version, then the install
succeeded.  One way in which this manifested itself, is that the
driver seem to work, but would not load GLX.

>
> FYI, 7NIF2 link:
>
>     http://www.chaintechusa.com/tw/eng/product_spec.asp?MPSNo=13&PISNo=15
>


I used to use a 440MX, and it worked Okay.  My 5700LE works noticeably
better, for HD playback, however.


> I'm definately getting closer!
>
> Thank you for all your help,
> Matt


Don't give up.  HighDef is a glorious thing, once you achieve it!

John