The following idl procedure will produce an mpeg file from a series of
images stored in a 3D array (width x height x # of frames). It requires
the "mpeg_encode" executable to be inthe unix search path. This can be
obtained from ftp://s2k-ftp.cs.berkeley.edu/pub/multimedia/mpeg/encode.
There are lots of options that can be handled differently, to make
tradeoffs between image quality, speed, and disk space. See the
documentation for mpeg_encode for more details.
If your animation is stored in the array "image_array" and you want to
write it to a file called "movie.mpg," you would do so by typing
WRITE_MPEG, 'movie.mpg', image_array
Best of luck!
--
A. Scott Denning scott@abyss.Atmos.ColoState.edu
Dept. of Atmospheric Science Phone (970)491-2134
Colorado State University Fax1 (970)491-8428
Fort Collins, CO 80523-1371 Fax2 (970)491-8449
======================== C U T H E R E ============================
PRO WRITE_MPEG, mpegFileName, image_array
movieSize = SIZE(image_array)
xSize = movieSize(1)
ySize = movieSize(2)
nFrames = movieSize(3)
nDigits = 1+FIX(ALOG10(nFrames))
formatString = STRCOMPRESS('(i'+STRING(nDigits)+'.'+STRING(nDigits)$
+ ')', /REMOVE_ALL)
; Load current color table into byte arrays
TVLCT, red, green, blue, /GET
red = BYTE(red)
green = BYTE(green)
blue = BYTE(blue)
ON_IOERROR, badWrite
; Make a temporary directory if necessary or clear it otherwise'
TMPDIR = '/tmp/idl2mpeg.frames'
SPAWN, 'if (-d ' + TMPDIR + ') echo "exists"', result
dirExists = result(0) EQ 'exists'
IF dirExists THEN command = 'rm ' + TMPDIR + '/*' $
ELSE command = 'mkdir ' + TMPDIR
SPAWN, command
; Write each frame into TMPDIR as an 8-bit .gif image file
FOR frameNum = 0, nFrames-1 DO BEGIN
fileName = TMPDIR + '/frame.' + STRING(frameNum,FORMAT=formatString)$
+ '.gif'
WRITE_GIF, fileName, image_array(*,*,frameNum), red, green, blue
ENDFOR
; Build the mpeg parameter file
paramFile = TMPDIR + '/idl2mpeg.params'
OPENW, unit, paramFile, /GET_LUN
PRINTF, unit, 'PATTERN IBBBBBBBBBBP'
PRINTF, unit, 'OUTPUT ' + mpegFileName
PRINTF, unit, 'GOP_SIZE 12'
PRINTF, unit, 'SLICES_PER_FRAME 5'
PRINTF, unit, 'BASE_FILE_FORMAT PPM'
PRINTF, unit, 'INPUT_CONVERT giftoppm *'
PRINTF, unit, 'INPUT_DIR /tmp/idl2mpeg.frames'
PRINTF, unit, 'INPUT'
PRINTF, unit, '`ls *.gif`'
PRINTF, unit, 'END_INPUT'
PRINTF, unit, 'PIXEL FULL'
PRINTF, unit, 'RANGE 5'
PRINTF, unit, 'PSEARCH_ALG LOGARITHMIC'
PRINTF, unit, 'BSEARCH_ALG SIMPLE'
PRINTF, unit, 'IQSCALE 8'
PRINTF, unit, 'PQSCALE 8'
PRINTF, unit, 'BQSCALE 8'
PRINTF, unit, 'REFERENCE_FRAME DECODED'
PRINTF, unit, 'FORCE_ENCODE_LAST_FRAME'
FREE_LUN, unit
; spawn a shell to process the mpeg_encode command
SPAWN, 'mpeg_encode ' + paramFile
RETURN
badWrite:
alert, 'Unable to write MPEG file!'
END
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