[MPlayer-dev-eng] ok to add new vf?

D Richard Felker III dalias at aerifal.cx
Mon Jul 29 06:33:08 CEST 2002


On Thu, Jul 27, 2000 at 12:16:20PM +0200, Arpi wrote:
> Hi,
> 
> > > > suppose you have to scale a 640x480 movie down to 640x240. Assuming
> > > > your codec outputs a planar colorspace such as yv12, the vertical
> > > > chroma resolution after scalind down will be 120. You've thrown away
> > > > half your chroma samples for no reason, since 240 lines of chroma
> > > > would still fit perfectly fine.
> > > > 
> > > > Here's where -vop halfpack comes in. It converts planar yuv input to
> > > > packed yuv (yuy2) output, halving the vertical luma resolution but
> > > > keeping all the original chroma samples.
> > > 
> > > hmm. what about just calling the 422p -> yuy2 converter, with doubled Y
> > > stride value and half height?
> > > 
> > > that code is already mmx etc optimized and is part of postproc/*
> > 
> > That would be nice, except it will just drop every other line of luma,
> > which will look horrible.
> 
> hmm. input from TV tuners is usually interlaced, so droping every second
> luma just looks better than interpolating them... imho.

Huh? This isn't for input from tv tuners. It's for output TO a tv!

Rich




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