/usr/bin/v4l2loopback-ctl is in v4l2loopback-utils 0.10.0-1ubuntu1.
This file is owned by root:root, with mode 0o755.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 | #!/bin/bash
usage() {
## ugly linebreaks in order to make help2man more happy
cat <<!
Usage:
$0 [command] [args]
Commands:
set-fps <FPS> /dev/videoX Set device fps (if format is already
negotiated).
set-timeout-image <IMAGE> /dev/videoX Set timeout on device, and
optionally the placeholder picture,
instead of default null frame.
set-caps <CAPS> /dev/videoX Fix format for the device (using GStreamer
caps), so it will be maintained until reset,
regardless of future readers/writers.
Options:
FPS frames per second, either as integer ('30') or fraction ('50/2')
IMAGE image file ("no-input.png"), or 'videotestsrc'
CAPS GStreamer caps ("video/x-raw-yuv, width=640, height=480"),
or 'any'
/dev/videoX the v4l2-loopback device file you want to act on
!
exit 1
}
version() {
cat <<!
$0 0.6
Copyright (c) 2012 IOhannes m zmoelnig <zmoelnig@iem.at>
Copyright (c) 2012 Anton Novikov (random.plant@gmail.com)
!
exit 1
}
die() {
echo "$@" 1>&2
exit 1
}
parse_device() {
if [ -e "$1" ]; then
device="$1"
elif [ -e "/dev/video$1" ]; then
device="/dev/video$1"
else
die "can't parse device"
fi
sysfs=/sys/devices/virtual/video4linux/${device##*/}
}
check_application() {
which $1 > /dev/null || die "can't find $1"
}
set_fps() {
fps="$1"
parse_device "$2"
[ -z "$fps" ] && usage
echo "@$fps" | sudo tee "$sysfs/format" >/dev/null || die "Set fps failed"
echo OK
}
set_caps() {
caps="$1"
parse_device "$2"
[ -z "$caps" ] && usage
[ "$caps" = 'any' ] && {
check_application v4l2-ctl
v4l2-ctl -d $device -c keep_format=0
return
}
[ -n "`cat $sysfs/format`" ] && die "Device is busy"
declare -a params
declare -a nofps_params
IFS=',' read -ra params <<< "$caps"
for p in "${params[@]}"; do
if echo "$p" | grep -q framerate; then
fps=`echo "$p" | sed -r 's/.*(=|\))//g'`
echo "$fps" | grep -q '[^0-9/]' && die "could not parse framerate param"
echo "@$fps" | sudo tee $sysfs/format >/dev/null || die "could not set fps attr"
#echo "fps: $fps"
else
nofps_params=("${nofps_params[@]}" "$p")
fi
done
{
IFS=','
nofps_caps="${nofps_params[*]}"
}
#echo "nofps_caps: $nofps_caps"
check_application v4l2-ctl
check_application gst-launch-1.0
v4l2-ctl -d $device -c keep_format=1 || exit 1
v4l2-ctl -d $device -c sustain_framerate=1 || exit 1
gst-launch-1.0 videotestsrc num-buffers=1 ! "$nofps_caps" ! v4l2sink device=$device || die "output to $device failed"
}
set_timeout_image() {
imagefile="$1"
parse_device "$2"
[ -z "$imagefile" ] && return
[ -n "`cat $sysfs/format`" ] || die "Device has no format negotiated"
check_application v4l2-ctl
check_application gst-launch-1.0
v4l2-ctl -d $device -c timeout_image_io=1
if [ "$imagefile" = 'videotestsrc' ]; then
gst-launch-1.0 videotestsrc num-buffers=1 ! v4l2sink device=$device
else
uri="file://`readlink -f $imagefile`" || die "no file"
echo "Reading from $uri"
gst-launch-1.0 uridecodebin uri=$uri ! videoconvert ! videoscale ! imagefreeze ! identity error-after=2 ! v4l2sink show-preroll-frame=false device=$device
fi
timeout=`v4l2-ctl -d $device -C timeout | sed -n 's/^timeout: //p'`
[ -n "$timeout" ] || die "couldn't get timeout"
echo "timeout: $timeout"
[ "$timeout" = 0 ] && {
echo 'Timeout is currently disabled; you can set it to some positive value, e.g.:'
echo "$ v4l2-ctl -d $device -c timeout=3000"
}
}
command="$1"
shift
case "$command" in
"-h"|"--help")
usage
;;
"-v"|"--version")
version
;;
"set-fps")
set_fps "$@"
;;
"set-caps")
set_caps "$@"
;;
"set-timeout-image")
set_timeout_image "$@"
;;
*)
usage
;;
esac
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