[MPlayer-users] Confused about deinterlacing and scaling

[D Richard Felker III]

On Wed, Jul 28, 2004 at 11:48:32AM -0700, rcooley wrote:
> On Wed, 28 Jul 2004 13:20:02 -0400
> Jason Tackaberry <tack at sault.org> wrote:
> 
> > the only other choice is to deinterlace the whole thing,
> > which really lowers the quality if a lot of it is progressive.  
> 
> Wow...  You lost me there...  If it's progressive, then pp=lb shouldn't
> loose any quality at all.  The other deinterlacers would loose some
> quality, but lb should not.

Yes it will. pp=lb loses a LOT of quality. It's actually invertible
(or almost invertible) in a theoretical sense if your sample values
had infinite precision, but since they're integers in the range 0-255
there's no hope of inverting it. I would guess off the top of my head
it loses about 10-20% of the information compared to other
deinterlacers which lose 50%.

Rich