Pammixinterlace User Manual(General Commands ManPammixinterlace User Manual(1)
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 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-
lace.
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 recog-
nizes the following command line options:
-filter={linear,fir,ffmpeg}
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 ⟨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
netpbm documentation 22 February 2007 Pammixinterlace User Manual(1)
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