[mythtv-users] Stuttering video on mythtv 0.26

Ben Kelly kell4now at gmail.com
Sun Nov 18 01:25:56 UTC 2012

I recently upgraded to mythtv 0.26. Everything works fine, except for
some videos which have very bad stuttering. These videos play fine on
0.25. I've also checked mplayer, which plays them very smoothly as
well. I have an nvidia ION card and I'm using the "vdpau normal"
profile, but I've been through the others (OpenGL, etc) and the
problem is always the same on myth 0.26.

I used the video playback test under the Setup Wizard in the frontend.
SD is ok, but the HD test gets stutter. I've noticed that the log gets
filled with these on videos experiencing stutter (and this includes
the HD test):
"CoreContext mythplayer.cpp:2095 (PrebufferEnoughFrames)"

I've set the nvidia powermizer to max performance, updated to the 304
nvidia driver, turned off CPU scaling - none of which have made any

My setup is:
- Zotac Mag - Atom 330 CPU
- ION nvidia graphics
- Mythbuntu 12.04
- Mythtv 0.26

I'm at a bit of a loss where to go from here. I'm thinking *something*
has been changed in the internal player between 0.25 and 0.26 to cause
this issue, but have no idea what.

For reference, here is the results from qvdpau test:
qvdpautest 0.5.1
Intel(R) Atom(TM) CPU  330   @ 1.60GHz
NVIDIA GPU ION (C79) at PCI:3:0:0 (GPU-0)

VDPAU API version : 1
VDPAU implementation : NVIDIA VDPAU Driver Shared Library  304.43  Sun
Aug 19 20:44:13 PDT 2012


MPEG DECODING (1920x1080): 60 frames/s
MPEG DECODING (1280x720): 135 frames/s
H264 DECODING (1920x1080): 53 frames/s
H264 DECODING (1280x720): 109 frames/s
VC1 DECODING (1440x1080): 69 frames/s

MIXER WEAVE (1920x1080): 311 frames/s
MIXER BOB (1920x1080): 436 fields/s
MIXER TEMPORAL (1920x1080): 117 fields/s
MIXER TEMPORAL + IVTC (1920x1080): 75 fields/s
MIXER TEMPORAL + SKIP_CHROMA (1920x1080): 159 fields/s
MIXER TEMPORAL_SPATIAL (1920x1080): 34 fields/s
MIXER TEMPORAL_SPATIAL + IVTC (1920x1080): 27 fields/s
MIXER TEMPORAL_SPATIAL + SKIP_CHROMA (1920x1080): 38 fields/s
MIXER TEMPORAL_SPATIAL (720x576 video to 1920x1080 display): 128 fields/s

MULTITHREADED MPEG DECODING (1920x1080): 59 frames/s
MULTITHREADED MIXER TEMPORAL (1920x1080): 99 fields/
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