NAME

       pammixinterlace - mix adjacent lines to merge interlaced images

SYNOPSIS

       pammixinterlace

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

       [-adaptive]

       [infile]

DESCRIPTION

       This program is part of Netpbm(1).

       pammixinterlace  is  meant  to operate on an image which is the interlacing 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 corresponding 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  before  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 generate 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 pammixinterlace.

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

OPTIONS

       In addition to the options common to all programs based on libnetpbm (most notably -quiet,
       see
        Common  Options  ⟨index.html#commonoptions⟩  ),  pammixinterlace recognizes the following
       command line options:

       -filter={linear,fir,ffmpeg}
              This option chooses between one of the three filtering  mechanisms.   linear  is  a
              linear-blend formula.  fir is a size-5 FIR low-pass filter, and ffmpeg is a formula
              pulled from the documentation of the program ffmpeg ⟨http://ffmpeg.mplayerhq.hu⟩ .

              The default is fir.

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

SEE ALSO

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

DOCUMENT SOURCE

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

              http://netpbm.sourceforge.net/doc/pammixinterlace.html