[MPlayer-users] Comparison of different deinterlace and denoise filters

[Matthias Wieser]

Am Mittwoch, 22. Oktober 2003 05:38 schrieb D Richard Felker III:

> > Strange: when recorded without anything, it's interlaced (two pixel
> > wide lines: two from frame one, two from frame 2, two from frame
> > one,...), but produced the mentioned artifacts.
>
> Yes, this is the only correct way to store interlaced video in 4:2:0
> format. Unfortunately it's displayed totally wrong, but that's life...

I have found the reason for the wrong chroma:
I used

mplayer /big/Medien/Video/videotest/raw_ntv.avi -ss 00:00:07 -vf 
crop=680:528:20:22,pp=md -frames 15 -forceidx -vo png -nosound -z 6

to create the test frames. I crop 22 lines away. If I use

mplayer /big/Medien/Video/videotest/raw_ntv.avi -ss 00:00:07 -vf 
crop=680:528:20:24,pp=md -frames 15 -forceidx -vo png -nosound -z 6

everything is ok! (crop has to be crop=680:528:20:(4*n) )


> Once you have interlaced 4:2:0 video like this, you can display it
> properly (still interlaced) with -vf ilpack.

When exactly do I need -vf ilpack?
When I don't deinterlace it (for example grab a kino film as mpeg4) then I 
think I don't need ilpack.

> And of course it's ready
> for deinterlacing or inverse telecine.

And I don't need lipack for deinterlacing with lb, md or fd.

Is it right to say, I need ilpack only if I crop n*4+2 lines away?

> Interlaced video is such a mess... :(

That's right!

> > When recorded with YUY2, chroma is normally interlaced (one pixel
> > wide lines).
>
> What format are you recording it in? Could you tell me the command
> lines that gave you the different results?

Of course:
mencoder tv:// -tv driver=v4l2:width=720:height=576:\ 
alsa:brightness=5:contrast=0:saturation=20:volume=40\
-ovc copy \
-oac mp3lame -lameopts cbr:br=128 \
-o Video-`date +%d.%m.-%H%MUhr`.avi -endpos 00:00:10 -v

for the standard (YV12) video.

mencoder tv:// -tv driver=v4l2:width=720:height=576:\ 
alsa:brightness=5:contrast=0:saturation=20:volume=40:outfmt=yuy2 \
-ovc copy \
-oac mp3lame -lameopts cbr:br=128 \
-o Video-`date +%d.%m.-%H%MUhr`-yuy2.avi -endpos 00:00:10 -v

for the yuv2 video.

To put it in a nutshell:

- Yuv2 video produced by a saa7134 card does never give chroma errors. But
  realtime capture to mpeg4 is slow.

- YV12 video produced by a saa7134 card does only give chroma errors when
  clipped by not (n*4) lines. You can crop a former recorded YV12 rawvideo
  by (n*4+2) lines, if you use 
  -vf format=yuy2,il=d:d,scale,format=yv12,il=i:i,...

- YV12 video produced by a bttv card does give chroma errors except for
   using "-tv outfmt=yuy2 -vf il=d:d,scale,format=yv12,il=i:i,..."

Regards,
    Matthias