tvtime vs xawtv

[Wes Shull]

(this is a copy of the comment I tacked onto Shrek's bugzilla #117651)

I agree that FC2 should include both xawtv and tvtime.

There are several reasons why Shrek may be getting suboptimal 
performance out of tvtime.  The reason tvtime looks so good (when 
the system can handle it) is that it can apply some very nice 
deinterlacing algorithms to the video before displaying it.  This 
leads to a big tree of performance dependencies: 
 
-> it has to run in capture mode instead of overlay mode (tvtime 
does not support overlay mode at all) 
   -> greater I/O load since all the data is going through the CPU 
      -> your card and driver have to support and use DMA or you're 
not going be able to get reasonable framerates at any resolution (a 
common failure mode is like what you're seeing; the CPU hasn't 
finished copying one frame before it's time for the next, so you get 
"tearing" where the image becomes the next frame, or just garbage) 
-> greater CPU load from 
   -> postprocessing (depends on which deinterlacing mode you have 
selected) 
   -> video output (especially if your display card/driver doesn't 
support Xv) 
 
>From the ultra-low cpu utilization in Shrek's xawtv ps, I'm guessing 
he's running xawtv in overlay mode?

...

Anyway the point is, it's normal for tvtime to use more cpu than 
xawtv.  In fact, I'm not sure I believe the person who said tvtime 
uses *less* cpu on his sytem, unless he's running xawtv in capture 
mode for some reason.

-- 
rawhide hasn't eaten my babies yet, but it did eat my .sig