zbarcam - Man Page

• Continuously read barcodes and print them to stdout: zbarcam
• Disable output video window while scanning: zbarcam --nodisplay
• Print barcodes without type information: zbarcam --raw
• Define capture device: zbarcam /dev/video_device

tldr.sh

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​.

zbarimg(1)

http://zbar.sf.net/

See http://sf.net/tracker/?group_id=189236&atid=928515

Jeff Brown <​spadix@users.sourceforge.net​>

Copyright © 2007-2010 Jeff Brown

All Rights Reserved