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Pammixinterlace	User Manual(0)			Pammixinterlace	User Manual(0)

       pammixinterlace - mix adjacent lines to merge interlaced	images


       [-filter={linear, fir, ffmpeg}]



       This program is part of Netpbm(1).

       pammixinterlace	is meant to operate on an image	which is the interlac-
       ing of two images, where	raster rows 0, 2, 4, etc. are from  one	 image
       and  rows 1, 3, 5, etc. are from	another.  (See below for why you might
       expect to encounter such	an image).

       pammixinterlace makes each row of the output a mixture  of  the	corre-
       sponding	 row  of the input and its two neighbors.  It uses half	of the
       main row	and a quarter each of the two neighbor rows.

       This can	be useful if the image is a video capture from	an  interlaced
       video source.  In that case, each row shows the subject 1/60 second be-
       fore or after the two rows that surround	it.  If	the subject is moving,
       this can	detract	from the quality of the	image.

       In video	data streams, you often	find each frame	contains only half the
       rows of the image -- the	odd half or the	even half.  The	 displayer  of
       the stream displays the rows in their proper positions on a CRT as they
       come in.	 When you display the rows in this order,  the	CRT  has  less
       flicker because a particular area of the	screen gets refreshed twice as
       often.  In the process of capturing such	a stream, computers often gen-
       erate the interlaced image of the type that pammixinterlace works with.
       But this	interlaced image, when displayed on a CRT, does	not  look  the
       same  as	 if a displayer	were rendering the stream directly on a	CRT as
       it arrived, because of the timing of when the various pixels get	 drawn
       and subsequently	fade.  That's why you need something like pammixinter-

       You may prefer the effect of simply extracting one of two images.   You
       can do that with	pamdeinterlace.

	      This  option  chooses  between one of the	three filtering	mecha-
	      nisms.  linear is	a linear-blend formula.	 fir is	a  size-5  FIR
	      low-pass	filter,	 and ffmpeg is a formula pulled	from the docu-
	      mentation	of the program ffmpeg <> .

	      The default is fir.

	      This option turns	on "adaptive" filtering	mode.	In  this  mode
	      pammixinterlace  modifies	only pixels that are obviously part of
	      a	"comb" pattern.

       pamdeinterlace(1), pam(5) pnm(5)

       This manual page	was generated by the Netpbm tool 'makeman'  from  HTML
       source.	The master documentation is at

netpbm documentation	       22 February 2007	Pammixinterlace	User Manual(0)


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