[MPlayer-users] deinterlacing help

[D Richard Felker III]

OK, a little update on this issue. The luma channel is not interlaced
at all, but was handled properly during encoding. However, chroma
channels are interlaced in the pattern 1221, which translates to
11222211 on the display since chroma is sampled at half the frequency.
Naturally this looks horrid when there are sudden changes in color,
e.g. colored lights turning on and off.

I found one way around the problem, but it lowers chroma quality quite
a bit:

-vop il=ic,scale,il=dc -ssf cgb=0.8

The il filter separates the image into two copies which are interlaced
with the patterns 12 and 21, and then the gaussian blur kills the "high
frequency noise" of the interlacing, and the il filter puts it back
together at the end.

So, here's what I want: either an option for vf_il to only separate
the chroma channels and leave luma alone, or better yet an option to
make the deinterlace filters leave luma alone and only deinterlace
chroma. I suppose if no one else is interested I'll write one of these
myself later...

Rich


On Thu, Oct 31, 2002 at 03:45:21PM -0500, D Richard Felker III wrote:
> [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
> I've run into quite a few broken interlaced files that have fields in
> the following pattern: 122112211221... i.e. field 1 appears on lines
> that are 0 or 3 mod 4, and field 2 appears on lines that are 1 or 2
> mod 4. I have no idea how the files came to be like this. Apparently
> it's some broken scale plugin for VirtualDub, which scaled PAL DVD
> down from 720x576 to 400x320 and made stupid decisions about how to
> handle interlacing. In any case, the new vf_il filter has helped
> greatly in diagnosing the problem, but I still don't know how to fix
> it. -vop il=ic,pp=lb,il=dc cures the interlacing, but of course that
> also mixes lines that don't belong next to each other, resulting in
> some new ugly artifacts.
> 
> Are there any existing filters that might clean up this mess for me?
> Or might it be possible to tweak one of them to do what I want? I've
> had these bad files for quite some time now, and now that the vf_il
> filter has made the nature of the problem clear (via -vop il=dc,il=dc
> separating the image into four "fields"), I'm hoping I might finally
> be able to fix them!
> 
> Rich