[mythtv-users] re: choppy HD playback

[Doug Larrick]

Brandon Beattie wrote:
>  At one point someone mentioned they were
> going to write a couple new deinterlacing algorithms to help, but that
> was a couple months ago.  

That was me... I essentially put that project on hold when I heard that 
nVidia was going to start supporting interlaced output modes in the next 
version of their closed-source driver... of course, it was promised for 
"March" but it's now about March 45th and we haven't seen it yet :-D .

I do have a working "top field" deinterlacer (throws away the bottom 
field), which works better than the current field-averager for 
high-motion video, plus is almost 0 CPU cost.  But the work I've done to 
support deinterlacers that double the frame rate is stalled because it 
makes the video quite jerky, due to deficiencies in the current video 
sync methods... so I'm trying to use OpenGL for video sync (which I've 
seen reports of success with) rather than the nVidia vsync support, but 
it consumes a lot of CPU :-( ... and so I just dig myself deeper, and 
keep hoping nVidia will come through with the interlaced-output goods.

I may package up and submit the topfield deinterlacer for people to play 
with if I get some time.  If you're interested, please pester me.

I get decent playback on my P4 2.8 GHz system.  The thing that helped 
the most was compiling libavcodec with -march=pentium4 ... this cut my 
CPU usage to ~65%-75% (normal Xv, not XvMC).  You might try something 
similar with some Athlon-specific -march tuning.

-Doug
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