NAME

       ra_rgbe - convert between different RADIANCE picture types

SYNOPSIS

       ra_rgbe [ -r ][ -e +/-stops ][ -f ][ -n frameno ] [ input [ outspec ] ]

DESCRIPTION

       Ra_rgbe  converts  between  RADIANCE  run-length  encoded  and  flat  formats, and separates concatanated
       animation frames produced by rpict(1).  The -e option  specifies  an  exposure  compensation  in  f-stops
       (powers  of  two).   Only integer stops are allowed, for efficiency.  By default, ra_rgbe produces a flat
       RADIANCE picture file from any type of RADIANCE input picture.  The -r option causes ra_rgbe to produce a
       run-length encoded file instead.

       If the input file consists of multiple animation frames as produced by rpict with the -S option,  ra_rgbe
       will  read  each  frame  and  write  it  to  the output file created by calling printf(3) with the output
       specification and frame number as arguments.  If the output specification begins with an exclamation mark
       ('!'), then this interpreted as a command spec., which is also run through printf with the  frame  number
       to  get  the  final  command.  This command must accept a Radiance picture on its standard input, and may
       write results either to a file or to the standard output.  The -n option may be used to select a specific
       frame for output, and other frames in the input will be skipped.  Normally, all frames will be  read  and
       written.

       Ra_rgbe  will  report an error and exit if the target output file already exists, unless the -f option is
       given.  If the output file is missing, the standard output is used.  If the input file is missing or  set
       to '-', the standard input is used.

NOTES

       The  file format for RADIANCE pictures was changed between release 1.4 and release 2.0.  The older format
       can still be read by all the programs, but only the newer format is produced.  This newer  format  cannot
       be read by RADIANCE software prior to release 2.0.

       Ra_rgbe  provides  some  downward  compatibility  by  producing  files that can be read by older RADIANCE
       software.  The resultant files are also easier to manipulate with programs designed to  read  raw  raster
       data.

       The other use for ra_rgbe is as a quicker way to adjust the exposure of a RADIANCE picture than pfilt(1),
       since  ra_rgbe  only  allows  integer  f-stop  changes.  In this mode, ra_rgbe should be used with the -r
       option.

AUTHOR

       Greg Ward

ACKNOWLEDGEMENT

       Work on this program was initiated and sponsored by the LESO group at EPFL in Switzerland.

SEE ALSO

       pfilt(1), printf(1), ra_xyze(1), rpict(1)

RADIANCE                                             1/23/98                                          RA_RGBE(1)