[mythtv-users] Choppy video and sound

Wed Jan 4 05:20:02 UTC 2006

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?  :)

> 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

> 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 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?

> 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

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).

FYI, 7NIF2 link:

    http://www.chaintechusa.com/tw/eng/product_spec.asp?MPSNo=13&PISNo=15

Here's the rest of the mythfrontend log, which may also be of
interest:

2006-01-03 23:03:53.347 Refresh rate: 16665, frame interval: 33366
2006-01-03 23:03:53.352 A/V diverged by -3.73134 frames, dropping frame to keep audio in sync
2006-01-03 23:03:53.353 A/V diverged by -6.26761 frames, dropping frame to keep audio in sync
2006-01-03 23:03:53.354 A/V diverged by -7.93002 frames, dropping frame to keep audio in sync
2006-01-03 23:03:53.355 A/V diverged by -8.92957 frames, dropping frame to keep audio in sync
2006-01-03 23:03:53.355 A/V diverged by -9.432 frames, dropping frame to keep audio in sync
2006-01-03 23:03:53.356 A/V diverged by -9.56905 frames, dropping frame to keep audio in sync
2006-01-03 23:03:53.357 A/V diverged by -9.43206 frames, dropping frame to keep audio in sync

[ ... several messages similar to above deleted ...]

2006-01-03 23:03:53.423 HandleGopStart: gopset not set, syncing positionMap
2006-01-03 23:03:53.436 Filling position map from 3 to 2
2006-01-03 23:03:53.452 Position map filled from Encoder to: 2
2006-01-03 23:03:53.452 SyncPositionMap liveTV, from Encoder: 3 entries
2006-01-03 23:03:53.453 Stream initial keyframedist: 15.
2006-01-03 23:03:53.453 positionMap[ 2 ] == 610342.
2006-01-03 23:03:53.982 positionMap[ 3 ] == 952358.
2006-01-03 23:03:54.476 positionMap[ 4 ] == 1296422.
2006-01-03 23:03:55.009 positionMap[ 5 ] == 1667110.
2006-01-03 23:03:55.439 positionMap[ 6 ] == 2021414.
2006-01-03 23:03:55.984 positionMap[ 7 ] == 2365478.
'video_output' mean = '28523.38', std. dev. = '12526.83', fps = '35.06'

[ ... several messages similar to above deleted ...]

2006-01-03 23:04:17.975 prebuffering pause
2006-01-03 23:04:17.975 waiting for prebuffer...
2006-01-03 23:04:18.001 RemoteFile::Read() failed in RingBuffer::safe_read().
2006-01-03 23:04:18.113 prebuffer wait timed out..
2006-01-03 23:04:18.114 waiting for prebuffer...
2006-01-03 23:04:18.217 RemoteFile::Read() failed in RingBuffer::safe_read().
2006-01-03 23:04:18.253 prebuffer wait timed out..
2006-01-03 23:04:18.253 waiting for prebuffer...
2006-01-03 23:04:18.393 prebuffer wait timed out..
2006-01-03 23:04:18.393 waiting for prebuffer...
2006-01-03 23:04:18.433 RemoteFile::Read() failed in RingBuffer::safe_read().
2006-01-03 23:04:18.533 prebuffer wait timed out..
2006-01-03 23:04:18.533 waiting for prebuffer...
2006-01-03 23:04:18.649 RemoteFile::Read() failed in RingBuffer::safe_read().
2006-01-03 23:04:18.673 prebuffer wait timed out..
2006-01-03 23:04:18.673 waiting for prebuffer...
2006-01-03 23:04:18.813 prebuffer wait timed out..
2006-01-03 23:04:18.813 waiting for prebuffer...
2006-01-03 23:04:18.865 RemoteFile::Read() failed in RingBuffer::safe_read().
2006-01-03 23:04:18.953 prebuffer wait timed out..
2006-01-03 23:04:18.953 waiting for prebuffer...
2006-01-03 23:04:19.081 RemoteFile::Read() failed in RingBuffer::safe_read().
2006-01-03 23:04:19.093 prebuffer wait timed out..
2006-01-03 23:04:19.093 waiting for prebuffer...
2006-01-03 23:04:19.233 prebuffer wait timed out..
2006-01-03 23:04:19.253 Changing from WatchingLiveTV to None
2006-01-03 23:04:19.261 Changing from None to None

I'm definately getting closer!

Thank you for all your help,
Matt

-- 
Matt Garman
email at: http://raw-sewage.net/index.php?file=email