[mythtv] packed image format and new deinterlacers

Markus Schulz msc at antzsystem.de
Fri Sep 15 20:33:30 UTC 2006


i'm currently study the mythtv source. I'm looking for the chance to get 
some alternative deinterlacers working. Especially the DScaler Greedy 
High Motion deinterlacer was one of my main interests.

But there are some problems, currently only planar pixel formats are 
supported with mythtv. This results in big changes to all DScaler 
Plugins or worde results (call on each plane would result in worse 
output, cause code is written for packed data). 
I'm sure i can expand the convert plugin to convert the framebuffer data 
to yuy2 packed format and back again after running deinterlacer. But 
this badly affects performance. 

Next problem was that most of Dscaler Deinterlacers needs the up to 6 
precedent fields (3 Frames). But each plugin only gets the current 
frame. Now i can save each frame inside plugin, but this also bates 

Furthermore i don't understand the frames a plugin will get for 
interlaced material. It looks so if i get only 25 fps (50Hz PAL 
Material) full frames weaved together. It would be nice to get the 
fields at 50Hz weaved (similar to current bob algo) with alternate 
top/botton field first.

Perhaps this would clear with the following:

Currently i got: (25FPS for PAL)
Plugin Call: Frame with Field 1 + 2
Plugin Call: Frame with Field 3 + 4

Nice would: (50FPS)
Plugin Call: Frame with Field 1 + 2 (top first)
Plugin Call: Frame with Field 2 + 3 (bottom first)
Plugin Call: Frame with Field 3 + 4 (top first) ...

It would be nice to hear some comments on this, i would like to put some 
of the DScaler deinterlacers into mythtv. But at least the frame 
history is a must have for this.

Any Suggestions?

Markus Schulz

A: Because it breaks the logical sequence of discussion
Q: Why is top posting bad?

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