1Pammixinterlace User Manual(0)                  Pammixinterlace User Manual(0)
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NAME

6       pammixinterlace - mix adjacent lines to merge interlaced images
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SYNOPSIS

10       pammixinterlace
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12       [-filter={linear, fir, ffmpeg}]
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14       [-adaptive]
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16       [infile]
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DESCRIPTION

21       This program is part of Netpbm(1).
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23       pammixinterlace  is meant to operate on an image which is the interlac‐
24       ing of two images, where raster rows 0, 2, 4, etc. are from  one  image
25       and  rows 1, 3, 5, etc. are from another.  (See below for why you might
26       expect to encounter such an image).
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28       pammixinterlace makes each row of the output a mixture  of  the  corre‐
29       sponding  row  of the input and its two neighbors.  It uses half of the
30       main row and a quarter each of the two neighbor rows.
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32       This can be useful if the image is a video capture from  an  interlaced
33       video  source.   In  that  case, each row shows the subject 1/60 second
34       before or after the two rows that surround it.  If the subject is  mov‐
35       ing, this can detract from the quality of the image.
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37       In video data streams, you often find each frame contains only half the
38       rows of the image -- the odd half or the even half.  The  displayer  of
39       the stream displays the rows in their proper positions on a CRT as they
40       come in.  When you display the rows in this order,  the  CRT  has  less
41       flicker because a particular area of the screen gets refreshed twice as
42       often.  In the process of capturing such a stream, computers often gen‐
43       erate the interlaced image of the type that pammixinterlace works with.
44       But this interlaced image, when displayed on a CRT, does not  look  the
45       same  as  if a displayer were rendering the stream directly on a CRT as
46       it arrived, because of the timing of when the various pixels get  drawn
47       and subsequently fade.  That's why you need something like pammixinter‐
48       lace.
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50       You may prefer the effect of simply extracting one of two images.   You
51       can do that with pamdeinterlace.
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OPTIONS

56       In  addition  to  the options common to all programs based on libnetpbm
57       (most notably -quiet, see
58        Common Options ⟨index.html#commonoptions⟩  ),  pammixinterlace  recog‐
59       nizes the following command line options:
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64       -filter={linear,fir,ffmpeg}
65              This  option  chooses  between one of the three filtering mecha‐
66              nisms.  linear is a linear-blend formula.  fir is a  size-5  FIR
67              low-pass  filter,  and ffmpeg is a formula pulled from the docu‐
68              mentation of the program ffmpeg ⟨http://ffmpeg.mplayerhq.hu⟩ .
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70              The default is fir.
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73       -adaptive
74              This option turns on "adaptive" filtering mode.   In  this  mode
75              pammixinterlace  modifies only pixels that are obviously part of
76              a "comb" pattern.
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SEE ALSO

83       pamdeinterlace(1), pam(1) pnm(1)
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DOCUMENT SOURCE

86       This manual page was generated by the Netpbm tool 'makeman'  from  HTML
87       source.  The master documentation is at
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89              http://netpbm.sourceforge.net/doc/pammixinterlace.html
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91netpbm documentation           22 February 2007 Pammixinterlace User Manual(0)