Subject: Re: [MPlayer-users] show interlaced/progressive info..

[D Richard Felker III]

On Fri, Nov 14, 2003 at 11:24:07AM +0000, rbtq7ol02 at sneakemail.com wrote:
> [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
> > On Fri, 14 Nov 2003, Tuukka Toivonen wrote:
> >
> > One idea I wonder if you have tried it: compute correlation first
> > between vertically adjacent scanlines, the compute correlation between
> > every other vertically adjacent scanline (leaving one scanline between)
> > and the compare the average correlation. If it is larger for scanlines
> > which have one scanline between them, then the video is likely to be
> > interlaced.
> 
> Erm...  this sounds very good.  Also potentially very fast, in MMX (or
> even better in SSE, with psadb).  My math says that keeping an
> accumulation of these differences over the whole image, even for insanely
> large images, is plausible, too (accumulated absolute difference should
> be well under 2^32, even for insane cases like 1920x1080 in RGB).  Mind
> if I try out this test for something else I'm working on for MythTV?

No offense, but this is the most obvious and naive way to do it, and
my results were nowhere near reliable enough to be conclusive...

Rich