[vlc-devel] [PATCH] Phosphor deinterlacer, reworked++

Juha Jeronen juha.jeronen at jyu.fi
Thu Mar 3 19:15:18 CET 2011

Hi again...

On 03/03/11 02:28, Juha Jeronen wrote:
> 2) With 4:2:0 chroma, it is impossible to change the chroma of just one
> field. For 4:2:2, it is possible to dim one field only for the chroma, too.

...and the design I talked about last night is still missing the 
possibility of AltLine in ComposeFrame(), and then upconvert to 4:2:2 
for the dimmer.

Theoretically doing that should look slightly better for telecined 
input, but in practice it doesn't really seem to matter.

For some curious reason, my MMX and C implementations for 4:2:2 chroma 
dimming - which should be equivalent - give slightly different looking 
images, but I've read through both a number of times and can't find a 
bug in either of them. The C version gives slightly more pronounced 
colours. Both look okay, though, so I think I'll declare this part 
complete (and open for comments along with the rest of the updated 
patch) for now.

My main observations about this are that if the chroma planes are 
dimmed, too, the colour representation indeed looks more accurate, 
especially for the higher dimmer strengths. And that the Atom N450 
really, really isn't fast enough for 4:2:2 at 60fps. I'll see if I can 
save a few MMX instructions per loop, but I'm not expecting that to 
really help :)

I'll finish the patch update and post it later tonight.


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