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)