[mythtv-users] jumpy playback (not suttering)

[Roger.M.Little at mchsi.com]

No, this is not another stuttering post.  I am noticing a jumpy (but consistent)
framerate when watching fast moving programs such as auto racing.  It's not as
noticeable with other slower-moving programming, such as sitcoms, but is still
there.  I have tried changing and disabling deinterlacing, changing capture
resolution/bitrates, made sure I am recording in NTSC mode, using different sync
methods (NVidia, RTC, and Busy wait).  Nothing seems to help except for using
Bob (double framerate) deinterlacing, but I don't like the effect it has on the
OSD text.  It looks like NTSC material is being played back at 18 or 24 fps, not
at full framerate.  While using DirecTivo or SageTV the framerate looks fine. 
Here are my system specs:

AMD Athlon 3200XP
NVidia Geforce FX5200 (and 5950 Ultra) using binary 4363 and 6111 driver
Asus A7N8X-E Deluxe Nforce2 motherboard
snd-intel8x0 alsa driver
Hauppauge PVR250
FC1 and FC2 using Jarrod's guides, both have same problem
Myth .16

I also stumbled across another problem where Myth would always use Linear Blend
(or one-field, forget which) deinterlacing no matter what was set in the
Playback setup screen, even when deinterlacing was turned off.  I moved from FC1
to FC2 to get around that problem.