NAME¶
vgrabbj.conf - configuration file for vgrabbj
OVERVIEW¶
vgrabbj purpose is to read data from a v4l-device and put it in a file,
formatted as jpeg, png, or pnm. Except for the ftp-options described below
everything can also handled on the commandline. Here the configuration
statements are described.
Syntax is <keyword> <value>. Comments start with a ';' or '#'. Those
lines are ignored by vgrabbj. Case of the keywords and named options doesn't
matter except for the timestamp option as well as any filename.
The configuration file is parsed line by line. If any keyword appears twice or
more often, the last one is the one used.
On startup, the pre-defined configuration file /etc/vgrabbj.conf is read. Then,
commandline parameters are evaluated one by one, the last is the most
significant, if one option is provide twice or more often. Same applies for
the commandline parameter -c <config-file>.
GENERAL OPTIONS¶
- DaemonSeconds seconds
- Daemonize & loop with seconds intervals (min. 1).
- Daemon microseconds
- Daemonize & loop microseconds intervals (min. 1). Same as
-l except you can control it more precisely.
- AutoBrightness On|Off
- Defines if vgrabbj's brightness adjustment is used. This option works only
if the device supports data fetch via read and RGB24 videopalette. See
ForcePalette on how-to set RGB24. Some device do not support RGB24,
hence, Brightness is ignored.
- ImageQuality quality
- Sets the quality of a jpeg output to quality (1-100, default:
75).
- ImageSize imagesize
- Sets the imagesize of input device, where imagesize is one of:
-
sqcif= 128x96, qsif = 160x120,
qcif = 176x144, sif = 320x240,
cif = 352x288, vga = 640x480,
svga = 800x600, xga = 1024x768,
sxga = 1280x1024, uxga = 1600x1200,
- (default: cif)
- ImageWidth width
- Sets the width of the image to width. Needs -H. The
v4l-device has to support the image width you set with this option.
- ImageHeight height
- Sets the height of the image to height. Needs -w. The
v4l-device has to support the image height you set with this option.
- OutputFormat format
- Sets the output to format (either jpeg, png, or
pnm, default: jpeg). Alternative, you may provide jpg for
jpeg.
- OutputFile <filename>
- Output is written to filename (default: /dev/stdout)
- Archive <path/filename>
- Additional output is written to path/filename (default: not
set), whereas the path-filename can include any strftime component.
The path- filename must not be on a different filesystem as the output
defined above. Additionally, you need to take care of the number of files
stored. There is no upper ceiling for archiving.
- VideoDevice <device>
- Sets the input device to device (default: /dev/video)
- OpenOnce On|Off
- Defines if vgrabbj opens the device only while image data is
grabbed ( Off) or keeps it opened while it is running (On).
Setting it to Off is helpful if you need access to the device
besides vgrabbj. This use is discouraged though, due to possible problems
with memory fragmentation. Default is On.
- SetImageSize On|Off
- Defines if the image size (see -i, -H, and -w) of the
device is set by vgrabbj. Necessary for certain v4l-devices which do not
support to be set to a particular image size (e.g. IBM-usb-cam, QuickCam).
For these devices you have to specify the size at module load time.
Default is On.
- SwitchColor On|Off
- Switches colormap from BGR to RGB (or vice versa) if set to On.
Default is Off. Use if you have odd colors.
- SwapRL On|Off
- Swaps left and right of the image like a mirror. Default: Off. is
Off.
- SwapTB On|Off
- Swaps top and bottom of the image like a mirror. Default: Off. is
Off.
- NoUseMmap On|Off
- Turns off the use of mmap'ed (better) memory allocation for grabbing
frames. Some (very rare) cams cannot use mmap'ed memory and have to use
read. If you want to switch easily, use this switch. If you don't know
what I'm talking about, leafe it like it is: Default is Off.
- DebugLevel value
- Sets the loglevel of vgrabbj. Valid for value are 0, 2, 3, 4, 6, 7
(default: 4). 0 means no messages at all, 7 is debug. Don't use 7 if you
are running vgrabbj in daemon mode, it'll surely fill your syslog. Be
aware, that loglevel 7 will also post you ftp-password (if defined) in the
logfile!
- UseTmpOut On|Off
- Sets the use of the temporary outputfile. Default is On. Ignored in
case the default output ( /dev/stdout) is used. If set to
Off, the data is written directly to the file defined by
OutputFile.
If filename is different from /dev/stdout (given via -f
parameter or OutputFile, vgrabbj defaults to use a temporary file
called filename.tmp to write the image. This file is then renamed
to filename to shorten the time period corrupt data may be read
from filename.
- Exec commands
- Ask vgrabbj to launch an external program. May be used to pass the picture
through ImageMagick or others filters. The first '%s' instance in the
command line will be replaced with filename. If UseTmpOut is
On, commands will be run before the file is renamed.
- ForcePalette palette
- Force the usage of the specified palette. If palette is not
supported by either vgrabbj or the v4l-device, fallback to a
palette supported by both is provided. If no common denominator is
available, vgrabbj exits. Supported palettes are marked with * below.
Possible values are (copy from videodev.h):
-
1 VIDEO_PALETTE_GREY Linear greyscale
2 VIDEO_PALETTE_HI240 High 240 cube (BT848)
3 VIDEO_PALETTE_RGB565 565 16 bit RGB
4 *VIDEO_PALETTE_RGB24 24bit RGB
5 *VIDEO_PALETTE_RGB32 32bit RGB
6 VIDEO_PALETTE_RGB555 555 15bit RGB
7 *VIDEO_PALETTE_YUV422 YUV422 capture
8 *VIDEO_PALETTE_YUYV
9 *VIDEO_PALETTE_UYVY
10*VIDEO_PALETTE_YUV420
10 VIDEO_PALETTE_YUV411 YUV411 capture
11 VIDEO_PALETTE_RAW RAW capture (BT848)
12 VIDEO_PALETTE_YUV422P YUV 4:2:2 Planar
13 VIDEO_PALETTE_YUV411P YUV 4:1:1 Planar
14*VIDEO_PALETTE_YUV420P YUV 4:2:0 Planar
15 VIDEO_PALETTE_YUV410P YUV 4:1:0 Planar
16 VIDEO_PALETTE_PLANAR
17 VIDEO_PALETTE_COMPONENT
- (no default, depends on v4l-device).
- DiscardFrames value
- value images are grabbed and immediately discarded. Only the last
image is written to the output. This might be helpful if your v4l-device
needs to take a couple of images to auto-adjust to the current light.
ARCHIVE OPTIONS¶
The following options are useful if you want to keep a certain amount of images
in an archive. Currently, the archive is only supported if kept on the same
filesystem as the images taken.
- Archive <archive-filename-pattern>
- The archive-filename-pattern is evaluated as a timestring, hence
the same applies as to TimeStamp (see below, default:
/tmp/arch/cam-%Y-%d-%m-%H-%M-%S.jpg)
- ArchiveEach <value>
- Defines how many images have to be taken before a copy is made for the
archive. E.g. if defined 1, each image is put in the archive; if defined 5
every fifth image is put in the archive.
- ArchiveMax <value>
- Sets the maximum number of images to be put in the archive.
TIMESTAMP OPTIONS¶
The following options are available only if vgrabbj was compiled with the
freetype library available. The timestamp will only be enabled if all values
evaluated (inlcuding defaults) lead to a valid configuration and UseTimestamp
is set to On.
- UseTimestamp On|Off
- This is the essential setting to enable timestamps if defined in the
config file. Without this being set to On, it just won't work (although,
if there are options set to have an invalid configuration, it won't work
either). This is different to the handling on the commandline.
- FontFile filename
- The TrueType font to be used for the timestamp (default
/usr/X11R6/lib/X11/fonts/TrueType/Arialn.ttf).
- FontSize size
- Set the fontsize to size for timestamp (3-100, default: 12).
- TimeStamp format-str
- Defines the timestamp. format-str can be plain text or any strftime
format. Any '""' at the beginning or the end will be eliminated
for compatibility reasons, i.e. they are not necessary (default: "%a,
%e. %B %Y - %T" - see strftime(3) for details).
- Position value
- Alignment of the timestamp in the image. Possible value:
-
ul = upper left, ur = upper right,
ll = lower left, lr = lower right,
uc = upper center, lc = lower center
- (default: upper right). You can use either the short or the long
version.
- Blend value
- Defines the blend between font background and image (1-100, default:
60).
- BorderSize value
- value pixels will be used as border around the timestamp string
(1-255, default: 2).
FTP OPTIONS¶
There are no options for ftp-upload on the command line. This is due to the need
to provide a password which would be visible via the
ps(1) command.
- EnableFtp On|Off
- Ftp-Connection will only be opened if set to On. Be aware that this
might bring up a dial-up connection. See also KeepAlive. (default:
Off)
- RemoteHost hostname
- Host to which a ftp-connection will be established everytime an image has
been written (see also: Daemon, DaemonSeconds,
KeepAlive, default: camimage.jpg).
- RemoteDir path
- The path consists of the full path on the remote host defined by
RemoteHost (default: /).
- RemoteImageName filename
- The filename consists of the full path and filename on the remote
host defined by RemoteHost (default: foo.bar.com).
- Username username
- The name of the user to log on the remote ftp-server (default: foo).
- Password password
- The password of the user to log on the remote ftp-server (default: bar).
Be aware, that the password is kept unencrypted in memory, it might be
read by others.
- KeepAlive On|Off
- If set to On, the connection will be kept. This will cause a
dial-up line to be up all the time, which in turn may cost a lot of money!
If set to Off, the connection will be established after an image
was written to the OutputFile. After transmission, the
ftp-connection will be ended. This may also result in phone charges, for
which Author takes no responsibility. See License.
- Passive On|Off
- If set to On, passive ftp will be used. This can help connecting to
ftp servers from the inside of a NAT-ed network.
- TryHarder On|Off
- Not implemented, yet.
HARDWARE SETTINGS¶
With the following options you may alter the settings of your hardware (the
cam), if supported by the cam. Be aware, this might break your hardware, as
there are no checks if the values supplied are valid, allowed, or supported!
- -W <value>
- Whiteness definition.
- -r <value>
- Color definition.
- -x <value>
- Contrast definition.
- -b <value>
- Brightness definition.
- -u <value>
- Hue definition.
BUGS¶
At my own machine running vgrabbj, the %F in a Archive-Filename causes memory
corruption. This is not validated by any other machine. No further bugs are
known at this time.
SEE ALSO¶
vgrabbj(1),
strftime(3),
ps(1)
AUTHOR¶
This manual page was originally written by Michael Janssen
<janssen@cns.uni.edu>, for the Debian GNU/Linux system and enhanced by
Jens Gecius <devel@gecius.de>.