NAME

       ppmtoyuv - convert a PPM image to an Abekas YUV file

SYNOPSIS

       ppmtoyuv [ppmfile]

DESCRIPTION

       This program is part of Netpbm(1).

       ppmtoyuv reads a PPM image as input and produces an Abekas YUV file as output.

       The  output file contains a raster of four byte YUV codes, each uniquely associated with two side-by-side
       pixels in the image.  The raster contains rows in order from top to bottom, and within each  row  columns
       from left to right.  So the output file size in bytes is twice the number of pixels in the image.

       Each YUV code is associated with two pixels from the input image that we will call the left pixel and the
       right pixel.  The 2nd byte of the code is the Y value of the left pixel.  The 4th byte of the code is the
       Y  value  of  the right pixel.  The 1st byte of the code is an average of the U value of the pixel to the
       left of the left pixel, the left pixel, and the right pixel.  The 3rd byte of the code is analogous for V
       values.  These averages are weighted arithmetic means where the left pixel is weighted  double  what  the
       other two pixels are weighted.

       This format is reminiscent of but rather different from the common YUV 4:2:0 format (aka YUV 420) and the
       similar  YUV  4:4:4,  YUV  4:2:2,  YUV  4:1:1,  YUV  4:1:1s,  and YUV 4:1:0.  In YUV 4:2:0, the raster is
       different for even numbered lines and odd numbered lines.  On even numbered lines,  there  are  twice  as
       many  bits  for  Y of each pixel as for U or V.  On odd numbered lines, there are the same number of bits
       for Y as on even numbered lines, but no bits at all for U and V.

       Another YUV-based format is YUV4MPEG2, which is a movie format normally used with  MJPEGTools  .   Netpbm
       does not have converters for this format, but MJPEGTools does.

OPTIONS

       There are no command line options defined specifically for ppmtoyuv, but it recognizes the options common
       to all programs based on libnetpbm (See  Common Options .)

SEE ALSO

       yuvtoppm(1), ppmtoeyuv(1), ppmtoyuvsplit(1), ppm(1), pnmtoy4m , y4mtopnm

AUTHOR

       Marc  Boucher  marc@PostImage.COM,  based  on Example Conversion Program, A60/A64 Digital Video Interface
       Manual, page 69.

       Copyright (C) 1991 by DHD PostImage Inc.

       Copyright (C) 1987 by Abekas Video Systems Inc.

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/ppmtoyuv.html

netpbm documentation                              06 June 2005                           Ppmtoyuv User Manual(1)