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#!/usr/bin/perl -w
# Copyright © 2001-2015 Jamie Zawinski <jwz@jwz.org>.
#
# Permission to use, copy, modify, distribute, and sell this software and its
# documentation for any purpose is hereby granted without fee, provided that
# the above copyright notice appear in all copies and that both that
# copyright notice and this permission notice appear in supporting
# documentation. No representations are made about the suitability of this
# software for any purpose. It is provided "as is" without express or
# implied warranty.
#
# This program attempts to grab a single frame of video from the system's
# video capture card, and then load it on to the root window using the
# "xscreensaver-getimage-file" program. Various frame-grabbing programs
# are known, and the first one found is used.
#
# The various xscreensaver hacks that manipulate images ("slidescreen",
# "jigsaw", etc.) get the image to manipulate by running the
# "xscreensaver-getimage" program.
#
# The various screen savers invoke "xscreensaver-getimage", which will in
# turn invoke this program, depending on the value of the "grabVideoFrames"
# setting in the ~/.xscreensaver file (or in the app-defaults file, usually
# /usr/lib/X11/app-defaults/XScreenSaver).
#
# Created: 13-Apr-2001.
require 5;
#use diagnostics; # Fails on some MacOS 10.5 systems
use strict;
my $progname = $0; $progname =~ s@.*/@@g;
my $version = q{ $Revision: 1.23 $ }; $version =~ s/^[^0-9]+([0-9.]+).*$/$1/;
my $tmpdir = $ENV{TMPDIR} || "/tmp";
my $tmpfile = sprintf("%s/xssv.%08x.ppm", $tmpdir, rand(0xFFFFFFFF));
my $verbose = 0;
# These are programs that can be used to grab a video frame. The first one
# of these programs that exists on $PATH will be used, and the image file
# is assumed to be written to $tmpfile (in some image format acceptable to
# "xscreensaver-getimage-file", e.g., PPM or JPEG.)
#
# If you add other programs to this list, please let me know!
#
my @programs = (
"bttvgrab -d q -Q -l 1 -o ppm -f $tmpfile", # BTTV
"qcam > $tmpfile", # Connectix Qcam
"gqcam -t PPM -d $tmpfile", # GTK+ Qcam clone
"v4lctl snap ppm full $tmpfile", # XawTV 3.94.
"streamer -a -s 768x576 -o $tmpfile", # XawTV
# the "-a" option ("mute audio") arrived with XawTV 3.76.
"atitv snap $tmpfile", # ATI video capture card
"grab -type ppm -format ntsc -source 1 " . # *BSD BT848 module
"-settle 0.75 -output $tmpfile",
"motioneye -j $tmpfile", # Sony Vaio MotionEye
# (hardware jpeg encoder)
"vidcat -b -f ppm -s 640x480 > $tmpfile 2>&-", # w3cam/ovcam
"vidtomem -f $tmpfile 2>&- " . # Silicon Graphics
"&& mv $tmpfile-00000.rgb $tmpfile",
# Maybe this works?
# "ffmpeg -i /dev/video0 -ss 00:00:01 -vframes 1 $tmpfile 2>&-",
# "mplayer -really-quiet tv://0 " . # Maybe works with some cams?
# "-ao null -vo pnm -frames 1 2>&- " .
# "&& mv 00000001.ppm $tmpfile",
);
sub error($) {
my ($e) = @_;
print STDERR "$progname: $e\n";
exit 1;
}
sub pick_grabber() {
my @names = ();
foreach my $cmd (@programs) {
$_ = $cmd;
my ($name) = m/^([^ ]+)/;
push @names, "\"$name\"";
print STDERR "$progname: looking for $name...\n" if ($verbose > 2);
foreach my $dir (split (/:/, $ENV{PATH})) {
print STDERR "$progname: checking $dir/$name\n" if ($verbose > 3);
if (-x "$dir/$name") {
return $cmd;
}
}
}
$names[$#names] = "or " . $names[$#names];
error ("none of: " . join (", ", @names) . " were found on \$PATH.");
}
sub grab_image() {
my $cmd = pick_grabber();
unlink $tmpfile;
print STDERR "$progname: executing \"$cmd\"\n" if ($verbose);
system ($cmd);
if (! -s $tmpfile) {
unlink $tmpfile;
error ("\"$cmd\" produced no data.");
}
print STDERR "$progname: wrote \"$tmpfile\"\n" if ($verbose);
print STDOUT "$tmpfile\n";
}
sub usage() {
print STDERR "usage: $progname [--verbose] [--name | --stdout]\n";
exit 1;
}
sub main() {
while ($_ = $ARGV[0]) {
shift @ARGV;
if (m/^--?verbose$/s) { $verbose++; }
elsif (m/^-v+$/s) { $verbose += length($_)-1; }
elsif (m/^--?name$/s) { } # ignored, for compatibility
elsif (m/^-./) { usage; }
else { usage; }
}
grab_image();
}
main;
exit 0;
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