r.out.mpeg(1grass) GRASS GIS User's Manual r.out.mpeg(1grass)
NAME
r.out.mpeg - Converts raster map series to MPEG movie.
KEYWORDS
raster, export, output, animation
SYNOPSIS
r.out.mpeg
r.out.mpeg --help
r.out.mpeg [-c] view1=name[,name,...] [view2=name[,name,...]]
[view3=name[,name,...]] [view4=name[,name,...]] output=name [qual-
ity=integer] [--overwrite] [--help] [--verbose] [--quiet] [--ui]
Flags:
-c
Convert on the fly, uses less disk space
Requires r.out.ppm with stdout option
--overwrite
Allow output files to overwrite existing files
--help
Print usage summary
--verbose
Verbose module output
--quiet
Quiet module output
--ui
Force launching GUI dialog
Parameters:
view1=name[,name,...] [required]
Name of input raster map(s) for view no.1
view2=name[,name,...]
Name of input raster map(s) for view no.2
view3=name[,name,...]
Name of input raster map(s) for view no.3
view4=name[,name,...]
Name of input raster map(s) for view no.4
output=name [required]
Name for output file
quality=integer
Quality factor (1 = highest quality, lowest compression)
Options: 1-5
Default: 3
DESCRIPTION
r.out.mpeg is a tool for combining a series of GRASS raster maps into a
single MPEG-1 (Motion Pictures Experts Group) format file. MPEG-1 is a
"lossy" video compression format, so the quality of each resulting
frame of the animation will be much diminished from the original raster
image. The resulting output file may then be viewed using your fa-
vorite mpeg-format viewing program. MPEG-2 and MPEG-4 provide much
better quality animations.
The user may define up to four "views", or sub-windows, to animate si-
multaneously. e.g., View 1 could be rainfall, View 2 flooded areas,
View 3 damage to bridges or levees, View 4 other economic damage, all
animated as a time series. A black border 2 pixels wide is drawn around
each view. There is an arbitrary limit of 400 files per view (400 ani-
mation frames). Temporary files are created in the conversion process,
so lack of adequate tmp space could also limit the number of frames you
are able to convert.
The environment variable GMPEG_SIZE is checked for a value to use as
the dimension, in pixels, of the longest dimension of the animation im-
age. If GMPEG_SIZE is not set, the animation size defaults to the rows
& columns in the current GRASS region, scaling if necessary to a de-
fault minimum size of 200 and maximum of 500. These size defaults are
overridden when using the -c flag (see below). The resolution of the
current GRASS region is maintained, independent of image size. Play-
back programs have to decode the compressed data "on-the-fly", there-
fore smaller dimensioned animations will provide higher frame rates and
smoother animations.
UNIX - style wild cards may be used with the command line version in
place of a raster map name, but wild cards must be quoted.
A quality value of quality=1 will yield higher quality images, but with
less compression (larger MPEG file size). Compression ratios will vary
depending on the number of frames in the animation, but an MPEG pro-
duced using quality=5 will usually be about 60% the size of the MPEG
produced using quality=1.
Example
r.out.mpeg view1="rain[1-9]","rain1[0-2]" view2="temp*"
If the number of files differs for each view, the view with the fewest
files will determine the number of frames in the animation.
With -c flag the module converts "on the fly", uses less disk space by
using r.out.ppm with stdout option to convert frames as needed instead
of converting all frames to ppm before encoding. Only use when encod-
ing a single view. Use of this option also overrides any size de-
faults, using the CURRENTLY DEFINED GRASS REGION for the output size.
So be careful to set region to a reasonable size prior to encoding.
KNOWN ISSUES
MPEG images must be 16-pixel aligned for successful compression, so if
the rows & columns of the calculated image size (scaled, with borders
added) are not evenly divisible by 16, a few rows/columns will be cut
off the bottom & right sides of the image. The MPEG format is optimized
to recognize image MOTION, so abrupt changes from one frame to another
will cause a "noisy" encoding.
NOTES
This program requires the program mpeg_encode (aka ppmtompeg):
MPEG-1 Video Software Encoder
(Version 1.3; March 14, 1994)
Lawrence A. Rowe, Kevin Gong, Ketan Patel, and Dan Wallach Computer
Science Division-EECS, Univ. of Calif. at Berkeley
Available from Berkeley: http://biowiki.org/BerkeleyMpegEncoder
or as part of the netpbm package (ppmtompeg): http://netpbm.source-
forge.net
Use of the -c flag requires the r.out.ppm GRASS module with the stdout
option.
SEE ALSO
r.out.ppm
AUTHOR
Bill Brown, U.S. Army Construction Engineering Research Laboratories
SOURCE CODE
Available at: r.out.mpeg source code (history)
Accessed: unknown
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GRASS 7.8.7 r.out.mpeg(1grass)
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