ppmntsc(1) [redhat man page]
PPMNTSC(1) General Commands Manual PPMNTSC(1) NAME
ppmntsc - Make RGB colors legal for NTSC or PAL color systems. SYNOPSIS
ppmntsc [ --pal ] [ --legalonly ] [ --illegalonly ] [ --correctedonly ] [ --verbose ] [ --debug ] [ infile ] Minimum unique abbreviations of options are acceptable. DESCRIPTION
This program makes colors legal in the NTSC (or PAL) color systems. Often, images generated on the computer are made for use in movies which ultimately end up on video tape. However, the range of colors (as specified by their RGB values) on a computer does not match the range of colors that can be represented using the NTSC (or PAL) systems. If an image with "illegal" colors is sent directly to an NTSC (or PAL) video system for recording, the "illegal" colors will be clipped. This may result in an undesirable looking picture. This utility tests each pixel in an image to see if it falls within the legal NTSC (or PAL) range. If not, it raises or lowers the pixel's saturation in the output so that it does fall within legal limits. Pixels that are already OK just go unmodified into the output. Input is from the file named input. If input is -, input is from Standard Input. If you don't specify input, input is from Standard Input. Output is always to Standard Output. This program handles multi-image PPM input, producing multi-image PPM output. OPTIONS
--pal Use the PAL transform instead of the default NTSC. --verbose Print a grand total of the number of illegal pixels. --debug Produce a humongous listing of illegal colors and their legal counterparts. NOTE: This option may produce a great deal of output. --legalonly Output only pixels that are already legal. Output black in place of pixels that are not. --illegalonly Output only pixels that are illegal (and output them uncorrected). Output black in place of pixels that are already legal. --correctedonly Output only pixels that are corrected versions of illegal pixels. Output black in place of pixels that are already legal. SEE ALSO
ppm(5), ppmdepth(1), ppmdim(1), ppmbrighten(1) AUTHOR
Wes Barris, Minnesota Supercomputer Center, Inc., Bryan Henderson 4th Berkeley Distribution April 19, 2000 PPMNTSC(1)
Check Out this Related Man Page
pnmremap(1) General Commands Manual pnmremap(1) NAME
pnmremap - replace colors in a PPM image with colors from another set SYNOPSIS
pnmremap [-floyd|-fs|-nfloyd|-nofs] [-firstisdefault] [-verbose] [-mapfile=mapfile] [-missingcolor=color] [pnmfile] All options can be abbreviated to their shortest unique prefix. You may use two hyphens instead of one to designate an option. You may use either white space or an equals sign between an option name and its value. DESCRIPTION
pnmremap replaces the colors in an input image with those from a colormap you specify. Where a color in the input is not in the colormap, you have three choices: 1) choose the closest color from the colormap; 2) choose the first color from the colormap; 3) use a color speci- fied by a command option. (In this latter case, if the color you specify is not in your color map, the output will not necessarily contain only colors from the colormap). Two reasons to do this are: 1) you want to reduce the number of colors in the input image; and 2) you need to feed the image to something that can handle only certain colors. To reduce colors, you can generate the colormap with ppmcolormap. Example: ppmcolormap testimg.ppm 256 >colormap.ppm ppmremap -map=colormap.ppm testimg.ppm >reduced_testimg.ppm To limit colors to a certain set, a typical example is to create an image for posting on the World Wide Web, where different browsers know different colors. But all browsers are supposed to know the 216 "web safe" colors which are essentially all the colors you can represent in a PPM image with a maxval of 5. So you can do this: ppmcolors 5 >websafe.ppm ppmremap -map=webafe.ppm testimg.ppm >websafe_testimg.ppm The output image has the same type and maxval as the map file. PARAMETERS
There is one parameter, which is required: The file specifcation of the input PNM file. OPTIONS -floyd -fs -nofloyd -nofs These options determine whether Floyd-Steinberg dithering is done. Without Floyd-Steinberg, the selection of output color of a pixel is based on the color of only the corresponding input pixel. With Floyd-Steinberg, multiple input pixels are considered so that the average color of an area tends to stay more the same than without Floyd-Steinberg. For example, if you map an image with a black, gray, gray, and white pixel adjacent, through a map that contains only black and white, it might result in an output of black, black, white, white. Pixel-by-pixel mapping would instead map both the gray pixels to the same color. -fs is a synomym for -floyd. -nofs is a synonym for -nofloyd. The default is -nofloyd. -firstisdefault This affects what happens with a pixel in the input image whose color is not in the map file. If you specify neither -firstisde- fault nor -missingcolor, pnmremap chooses for the output the color in the map which is closest to the color in the input. With -firstisdefault, pnmremap instead uses the first color in the colormap. If you specify -firstisdefault, the maxval of your input must match the maxval of your colormap. -missingcolor=color This affects what happens with a pixel in the input image whose color is not in the map file. If you specify neither -firstisde- fault nor -missingcolor, pnmremap chooses for the output the color in the map which is closest to the color in the input. With -missingcolor, pnmremap uses color. color need not be in the colormap. If you specify -missingcolor, the maxval of your input must match the maxval of your colormap. -verbose Display helpful messages about the mapping process. SEE ALSO
pnmcolormap(1), ppmcolors(1), pnmquant(1), ppmquantall(1), pnmdepth(1), ppmdither(1), ppmquant(1), ppm(5) AUTHOR
Copyright (C) 1989, 1991 by Jef Poskanzer. Copyright (C) 2001 by Bryan Henderson. 01 January 2002 pnmremap(1)