Radiance ra_rgbe program

RA_RGBE(1)                                                          RA_RGBE(1)

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 specifica-
       tion 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 stan-
       dard 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  pro-
       grams, 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)