[MPlayer-dev-eng] More on inverse telecine!

[D Richard Felker III]

On Mon, Apr 14, 2003 at 11:29:39AM -0500, Billy Biggs wrote:
> D Richard Felker III (dalias at aerifal.cx):
> 
> > On Mon, Apr 14, 2003 at 06:39:26AM -0500, Billy Biggs wrote:
> > > > >   No I just meant filter the input scanline with a low-pass filter
> > > > > before looking at absolte difference.  Like [1 4 6 4 1] before you do
> > > > > the abs.
> > > > 
> > > > Ah, hmm... This is fairly difficult to do without serious additional
> > > > computation, which would slow the process down even more. It could
> > > > have some benefits, but from a mathematical standpoint I don't think
> > > > you really get more info from the difference of the blurred lines than
> > > > the original difference before blurring. (I'd have to sit down and
> > > > work it out to be sure though...)
> > > 
> > > It's not that hard.  Even a [1 1 1 1] filter can help.  I've used
> > > something like this successfully on YUY2 content (luma every second
> > > byte):
> > 
> > Yes, but that ignores the fact that I'd need to do a whole block of
> > current and prev. frame at a time for processing, and the ugly
> > boundary conditions (what do you do on leftmost and rightmost pixels?)
> > etc.
> 
>   Huh?  This is a horizontal filter, you need only a scanline from the
> current field and a scanline from the previous field.  The leftmost and
> rightmost pixels you can drop anyway, as the edge conditions often
> contain noise anyway.

A temp buffer is needed so you don't damage the output frame by
blurring it, and you have to work by blocks rather than scanlines if
you want any worthwhile local information.

Rich