zbarcam - scan and decode bar codes from a video device
zbarcam [-qv] [--quiet]
[--nodisplay] [--xml] [--verbose[=n]]
[--prescale=WxH]
[-S[symbology.]config[=value]]
[--set [symbology.]config[=value]]
[device]
zbarcam {-h | --help |
--version}
zbarcam scans a video4linux video source (eg, a webcam) for
bar codes and prints any decoded data to the standard output. The video
stream is also displayed to the screen.
device is the path to the video4linux (version 1 or 2)
character device special file (major number 81 and minor number 0 thru 63).
It defaults to /dev/video0
The underlying library currently supports EAN-13 (including UPC
and ISBN subsets), EAN-8, DataBar, DataBar Expanded, Code 128, Code 93, Code
39, Codabar, Interleaved 2 of 5 and QR Code symbologies. The specific type
of each detected symbol is printed with the decoded data.
This program follows the usual GNU command line syntax. Single
letter options may be bundled, long options start with two dashes (`-').
-h, --help
Print a short help message describing command line
options to standard output and exit
--version
Print program version information to standard output and
exit
-v, --verbose[=n]
Increase debug output level. Multiple -v options
create more spew. Alternatively specify n to set the debug level
directly
-S[symbology.]config[=value],
--set
[symbology.]config[=value]
Set decoder configuration option
config for
symbology to
value.
value defaults to 1 if omitted.
symbology is one of
ean13,
ean8,
upca,
upce,
isbn13,
isbn10,
i25,
codabar,
code39,
code93,
code128,
qrcode or the special
value
*. If
symbology is omitted or
*, the
config
will be set for all applicable symbologies. These are the currently recognized
configs. Prefix a config with "no-" to negate it. Not all
configs are appropriate for every symbology.
enable
Control decoding/reporting of a symbology. For
symbologies which are just subsets of ean13 (upca, upce,
isbn13, isbn10), this config controls whether the subsets are
detected and reported as such. These special cases are disabled by default,
all other symbologies default to enabled
disable
Antonym for enable
emit-check
Control whether check digits are included in the decoded
output. Enabled by default. This config does not apply for code128,
which never returns the check digit. It also not apply for cases where the
check digit is disabled (see add-check). Check digits are currently not
implemented for i25 or code39
add-check
Enable decode and verification of a check digit for
symbologies where it is optional: this will include code39 and
i25, neither of which implements the check digit yet
ascii
Enable escape sequences that encode the full ASCII
character set. This would apply to code39, except that it's not
implemented either...
position
Enable collection of symbol position information. Enabled
by default. Currently, the position information is unusable, so you can save a
few cycles by disabling this.
test-inverted
Specially for QR code images, sometimes the image is
inverted, e. g. lines are written in white instead of black. This option makes
ZBar to invert the image and parse again, in case it fails using the normal
order. Enabling it affects all decoders.
min-length=n,
max-length=n
Bound the number of decoded characters in a valid symbol.
If a decode result is outside the configured min/max range (inclusive), it
will not be reported. Set to 0 to disable the corresponding check. This
setting applies to variable-length symbologies: i25, codabar,
code39, code128 and pdf417. min-length defaults to
6 for i25 and 1 for code39 (per Code 39 autodiscrimination
recommendation); all others default to 0
x-density=n,
y-density=n
Adjust the density of the scanner passes. Lower values
scan more of the image at the cost of decreased performance. Setting to 0
disables scanning along that axis. Defaults are both 1.
-q, --quiet
Quiet operation; disable the audible beep otherwise
emitted when a symbol is decoded
--nodisplay
Disable output video window. Video input will be scanned
until the program is interrupted or otherwise signaled
--xml
Stream results using an XML output format. This format
wraps the raw data from the symbol with information about the scan in an easy
to parse format. The latest schema is available from
http://zbar.sourceforge.net/2008/barcode.xsd--raw
Use raw symbol data output format. This format prints
symbol data separated by newlines without the additional symbology type
information that is printed by default
--prescale=WxH
Request video input scaling from the camera driver.
Possibly useful for reducing huge frames to achieve a higher frame rate. Note
that the driver may adjust or completely ignore the scaling request
Scan for barcodes using the second video device and pipe the
resulting data through a script that searches for each code in a database
and does something useful with them:
zbarcam /dev/video1 | upcrpc.py
The upcrpc.py example script included in the examples/
subdirectory of the distribution will make an XMLRPC call to a popular
internet UPC database and print the product description if found.
Scan for barcodes using the default video device and stream
results to stdout in XML format, also disable recognition of Interleaved 2
of 5 codes to prevent confusion with other symbologies or background
noise:
zbarcam --xml -Si25.disable
Scan only for Code 39, without using the preview window - maybe
for a fixed installation. To enable only Code 39, first all symbologies are
disabled, then Code 39 is re-enabled:
zbarcam --nodisplay -Sdisable -Scode39.enable
zbarcam returns an exit code to indicate the status of the
program execution. Current exit codes are:
0
Successful program completion.
1
An error occurred. This includes bad arguments and I/O
errors.
2
A fatal error occurred.
Jeff Brown <spadix@users.sourceforge.net>
Lead developer
Copyright © 2007-2010 Jeff Brown
All Rights Reserved